Re: SiO coating with a tantalum box
Don,
Yes, I am using a double port baffle box that has a single 1/2" discharge port out the side.? The 1/2" hole is really a little 1/2" dia well about an inch deep.? The SiO gas would be coming out of that well.?
Maybe you can compute the distribution from a sublimation source 24" away from target but I cant.? Could you give me the dummies version of how to do this ???? Or maybe help me thru it once. ??
Oh, I am about 4/5 thru your book.? Great read.? Got lots of questions on the plasma assisted deposition onto 3-D stuff but will chat with you offline on that.? If I had known how complex all this vacuum stuff was before I blundered into it I would have never bought that chamber.? I not smrt enough for this. ?
Drew
---------------------------------------------------------------------------------?
toggle quoted message
Show quoted text
On Wed, Oct 26, 2011 at 4:14 PM, SVC <donmattox@...> wrote:
?
Andrew,
I can't tell from your picture but are you using a "baffle box"
source? You can determine the distribution from the source by using a
material that sublimes (doesn't melt and wet) such as chromium instead
of the SiO.
Don
|
Re: SiO coating with a tantalum box
Andrew,
I can't tell from your picture but are you using a "baffle box"
source? You can determine the distribution from the source by using a
material that sublimes (doesn't melt and wet) such as chromium instead
of the SiO.
Don
Hey guys,?
It has been a long road but I finally have all the pieces of my SiO
over-coater set up and running at once in the 1.5 meter chamber.?
Commercial Tantalum box ( from Leskers ) with 280 amps x 4.8 vac
flowing thru it,?? 2 each 500 amp amperage pass-thru's that
don't get hot, a little electromechanical shutter vain thing with
aluminum foil on it to cover the output of the emitter box it while it
heats up,? XMS-1 crystal detector measuring the thickness ( old
but working perfectly ).? Aluminum deposition process laying down
shiny bright alunuinum.? Vacuum level ....... ummmm not sure but
somewhere in the low 10^ -4 millitorr's.
On my first full blast test I saw I saw a pathetic 0.1 nm / sec?
accumulation rate for the 15 seconds it ran.? I had a melt down
issue so had to cut it short.? The XMS-1 recorded 1.2 nm of
material total.? Yea I know that is sad but that is what I got on
the crystal before my amperage pass-thru started glowing red hot.?
I now have 2 each 500 + amp pass-thru in parallel so that is not going
to happen again.?
I ran the emitter box for 20 seconds to get it cherry red ( with all
the voltage and amperage it would take ) then opened the aluminum foil
shutter to expose the mirror and test plates.? The mirror and
witness plates showed no sign of over-coating protection for thier 15
seconds of exposure to the output.? The aluminum foil has a dull
gray "something " on it that came from the side facing the
emitter.? It don't look like aluminum to me.? I don't know
what SiO film looks like.? It is blasted on the foil exactly in
front of of the output from the tantalum box.? I have a chart of
deposited SiO nm vs colors but not any examples of the colors to go
by.? As you can see, my chamber has lots of colors in it already
from me screwing up all kinds of things over the last few months.
Now for the question :? Given that my tantalum box ( single 1/2"
dia output hole ) is 24" back from my 9" dia mirror and
glass plate targets,? how big a cone shaped distribution pattern
can I expect to cover ????? I was planning on setting up the
same way as you see in the picture attached so my crystal detector
will be about 5" from the center of the blast zone.??
Can I expect to see SiO 5" out from the center ?????
10" out ???? 20" out ???
Any help would be appreciated.? Pictures of what SiO looks like
when deposited would be very much appreciated.?
Drew in sunny Florida
?
Content-Type: image/jpeg; name="image.jpeg"
Content-ID:
X-Attachment-Id: ii_1334172c60a92ff4
Content-Type: image/jpeg; name="image.jpeg"
Content-ID:
X-Attachment-Id: ii_13341725815b03c5
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite? http://www.svc.org
|
SiO coating with a tantalum box
Hey guys,?
It has been a long road but I finally have all the pieces of my SiO over-coater set up and running at once in the 1.5 meter chamber.? Commercial Tantalum box ( from Leskers ) with 280 amps x 4.8 vac flowing thru it, ? 2 each 500 amp amperage pass-thru's that don't get hot, a little electromechanical shutter vain thing with aluminum foil on it to cover the output of the emitter box it while it heats up,? XMS-1 crystal detector measuring the thickness ( old but working perfectly ).? Aluminum deposition process laying down shiny bright alunuinum.? Vacuum level ....... ummmm not sure but somewhere in the low 10^ -4 millitorr's.
On my first full blast test I saw I saw a pathetic 0.1 nm / sec? accumulation rate for the 15 seconds it ran.? I had a melt down issue so had to cut it short.? The XMS-1 recorded 1.2 nm of material total.? Yea I know that is sad but that is what I got on the crystal before my amperage pass-thru started glowing red hot.? I now have 2 each 500 + amp pass-thru in parallel so that is not going to happen again.?
I ran the emitter box for 20 seconds to get it cherry red ( with all the voltage and amperage it would take ) then opened the aluminum foil shutter to expose the mirror and test plates.? The mirror and witness plates showed no sign of over-coating protection for thier 15 seconds of exposure to the output.? The aluminum foil has a dull gray "something " on it that came from the side facing the emitter.? It don't look like aluminum to me.? I don't know what SiO film looks like.? It is blasted on the foil exactly in front of of the output from the tantalum box.? I have a chart of deposited SiO nm vs colors but not any examples of the colors to go by.? As you can see, my chamber has lots of colors in it already from me screwing up all kinds of things over the last few months.
Now for the question :? Given that my tantalum box ( single 1/2" dia
output hole ) is 24" back from my 9" dia mirror and glass plate targets,? how big a cone shaped
distribution pattern can I expect to cover ??? ? I was planning on setting up the same way as you see in the picture attached so my crystal detector will be about 5" from the center of the blast zone. ? Can I expect to see SiO 5" out from the center ????? 10" out ???? 20" out ???
Any help would be appreciated.? Pictures of what SiO looks like when deposited would be very much appreciated.?
Drew in sunny Florida
?
|
Re: Evaporating aluminum from tungsten (or tantalum)
'Strong' was written about 1938 and? covered pnysics
department practices at Caltech at that time.? Very widely respected
book and there really isn't a modern equivalent.? A lot of his stuff on
instruments is of course obsolete after over 70 years but the basics
are as good today as they are then.? I'd recommend a copy for anyone
doing any kind of experiments.
Ed
Andrew Aurigema wrote:
toggle quoted message
Show quoted text
?
Jarvis,
I have that book somewhere.? I will look for it again.? But the fix for
me is to warm up the coils a little then turn them up to high and melt
the aluminum onto them.? I have tried it many ways and that is what
keeps the aluminum from falling off the coils.
Drew
---------------------------------------------------------------------
On Wed, Oct 5, 2011 at 12:00 PM, Jarvis
Krumbein <kpjarvis2003@...>
wrote:
?
Drew, in a previous reply I suggested that you get a
copy of "Proceedures in Experimental Physics" (attached).? That advice
still applies.? If you can't find a copy, I can copy the appropriate
pages and e-mail them to you.? I think that your filament wetting
problem could be solved .
?
Jarvis Krumbein
|
Re: Evaporating aluminum from tungsten (or tantalum)
Jarvis,
I have that book somewhere.? I will look for it again.? But the fix for me is to warm up the coils a little then turn them up to high and melt the aluminum onto them.? I have tried it many ways and that is what keeps the aluminum from falling off the coils.
Drew
---------------------------------------------------------------------
toggle quoted message
Show quoted text
On Wed, Oct 5, 2011 at 12:00 PM, Jarvis Krumbein <kpjarvis2003@...> wrote:
?
Drew, in a previous reply I suggested that you get a copy of "Proceedures in Experimental Physics" (attached).? That advice still applies.? If you can't find a copy, I can copy the appropriate pages and e-mail them to you.? I think that your filament wetting problem could be solved .
?
Jarvis Krumbein
Sent: Wednesday, October 5, 2011 6:18 AM
Subject: Re: [VacuumX] Evaporating aluminum from tungsten (or tantalum)
?
Well, the problems I was having were all thermodynamic in nature.? My little 500 BTU per hour water chiller simply could not take out the 6000 BTU's / hr that the diff pumps were putting into the water loop.? When I switched back to flowing 75 deg F tap water at about a gallon per minute once thru the diff pump water jackets and dump to the ground the problems went away.? I am now dedicating the little chiller to the vapor traps so they are running at like 55 deg F.? I can now run the diff pumps for the 3 hrs it takes to get the chamber down to aluminizing vacuum levels. ? ??
I am noticing that if I heat the tungsten coils slowly that the aluminum candy canes fall off the coils much more often.? When I heat the coils fast the aluminum canes melt in about 5 seconds and
wick onto the tungsten as they should.? Not sure how to fix this.? For now, I will heat the coils fast and pay the price of some tungsten oxide getting driven off the coils before the aluminum.?
Drew in sunny Florida
------------------------------------------------------------------------------------------------------------------------------
|
Re: Evaporating aluminum from tungsten (or tantalum)
Drew, in a previous reply I suggested that you get a copy of "Proceedures in Experimental Physics" (attached).? That advice still applies.? If you can't find a copy, I can copy the appropriate pages and e-mail them to you.? I think that your filament wetting problem could be solved .
?
Jarvis Krumbein
?
From: Andrew Aurigema To: VacuumX@... Sent: Wednesday, October 5, 2011 6:18 AM Subject: Re: [VacuumX] Evaporating aluminum from tungsten (or tantalum)
?
Well, the problems I was having were all thermodynamic in nature.? My little 500 BTU per hour water chiller simply could not take out the 6000 BTU's / hr that the diff pumps were putting into the water loop.? When I switched back to flowing 75 deg F tap water at about a gallon per minute once thru the diff pump water jackets and dump to the ground the problems went away.? I am now dedicating the little chiller to the vapor traps so they are running at like 55 deg F.? I can now run the diff pumps for the 3 hrs it takes to get the chamber down to aluminizing vacuum levels. ? ??
I am noticing that if I heat the tungsten coils slowly that the aluminum candy canes fall off the coils much more often.? When I heat the coils fast the aluminum canes melt in about 5 seconds and
wick onto the tungsten as they should.? Not sure how to fix this.? For now, I will heat the coils fast and pay the price of some tungsten oxide getting driven off the coils before the aluminum.?
Drew in sunny Florida
------------------------------------------------------------------------------------------------------------------------------
|
Re: Evaporating aluminum from tungsten (or tantalum)
Well, the problems I was having were all thermodynamic in nature.? My little 500 BTU per hour water chiller simply could not take out the 6000 BTU's / hr that the diff pumps were putting into the water loop.? When I switched back to flowing 75 deg F tap water at about a gallon per minute once thru the diff pump water jackets and dump to the ground the problems went away.? I am now dedicating the little chiller to the vapor traps so they are running at like 55 deg F.? I can now run the diff pumps for the 3 hrs it takes to get the chamber down to aluminizing vacuum levels. ? ??
I am noticing that if I heat the tungsten coils slowly that the aluminum candy canes fall off the coils much more often.? When I heat the coils fast the aluminum canes melt in about 5 seconds and wick onto the tungsten as they should.? Not sure how to fix this.? For now, I will heat the coils fast and pay the price of some tungsten oxide getting driven off the coils before the aluminum.?
Drew in sunny Florida
------------------------------------------------------------------------------------------------------------------------------
toggle quoted message
Show quoted text
On Mon, Sep 26, 2011 at 11:11 PM, SVC <donmattox@...> wrote:
?
When heating tungsten filaments to
evaporate aluminum the first thing that is vaporized is the tungsten
oxide. This is why you either need to strip the oxide off
(electropolising or by chemical cleaning using an oxidizing agent)
before heating or you should use a shutter (closed while premelting
the aluminum on the tungsten).? The aluminum will melt and wet
the tungsten at temperatures way below what is needed to evaporate the
aluminum. When the temperature is increased the aluminum will
evaporate Then open the shutter).? Don
|
Re: Evaporating aluminum from tungsten (or tantalum)
Andrew, see if you can get a copy of "Proceedures in Experimental Physics" by John Strong.? Originally published by Prentiss-Hall and later reprinted , I think by Willmann-Bell.? While no longer in print it contains the answers to many of your problems.? The chapter on coating (evaporation & sputtering) includes detailed instructions for prepareing evaporation sources and prefusing aluminum to tungstan coils.
?
Jarvis Krumbein
From: Andrew Aurigema To: VacuumX@... Sent: Tuesday, September 27, 2011 7:28 AM Subject: Re: [VacuumX] Evaporating aluminum from tungsten (or tantalum)
?
Don, I am always looking for vac feed thru.? May I inquire what fittings you have ??? Pre-melting the aluminum in vacuum in a separate vacuum run is just too much effort.? I have to let my chamber sit under vacuum for 12 hrs to de-gas or it takes forever to pump down.? So I think I will pre-melt all the emitters before I evaporate any of them.? The tips you ( and others ) have given me are very useful.? I can heat the tungsten coils up to the aluminum melting / wicking point slowly and then shut them down and move on to the next group to do the same.?? After all of them are wetted out, I can run them at high power to do the depositon.? I have an old XMS-1 thickness meter that clearly shows the nanometer per second deposition rate.? I usually see around 15 nm / second deposition rate with a full coil of aluminum and the deposition rate drops off fast after 10 seconds of power.?
That is about how long the aluminum last on the coils.? Hopefully a new procedure will reduce my tungsten oxide "soot" problem to just an annoying under layer that is covered by shiny aluminum.? I always fire my center coils last and shut them down early so the final layer of aluminum is as shiny as I can make it.? 5 years into vacuum coating and I still am not very proficient at? it.? Good thing I kept my day job :_)))))) Thanks again, Drew in soggy Florida ?-------------------------------------------------------------------------------------------------------------
On Tue, Sep 27, 2011 at 9:39 AM, SVC <donmattox@...> wrote:
?
Good point!! I left out the use of premelting the aluminum on the tungsten by heating it in vaciuum WITH NO SUBSTRATE in place.? Then open the chamber and mount the substrate - coat. I didn't think of this because it is obviously labor intensive. They use to sell prewetted filaments but I guess it wasn't profitable. If you use an evaporate-to-completion technique you can weigh the filament - prewet the tungsten with a small amount of aluminum then add enough Al to do the job. Aluminum will not evaporate much at its melting point.
Tungsten coils break because they crystallize on heating and become brittle. Limiting heating (and time) makes the coils last longer.
A general problem with evaporation from a filament or boat is that the evaporant is initally in poor thermal contact with the heated surface and so there is a tendency to over-heat the tungsten and as the aluminum melts, it spreads over the very hot surface and tends to spatter. Heat the filament slowly!! until the aluminum melts. Again - pre-cleaning the tungsten aids in wetting.
To clean the tungsten you can heat it in CLOROX on the stove.
DO NOT heat the tungsten/aluminum in air with a torch - you will only create a mess!
I have a bunch of evaporating filaments and vacuum chamber feedthroughs that I will part with if anyone has a particular need.
I also have two old (thyraton rectifier) high voltage (up to 5000 VDC) power supplies (no arc suppression) in ALBUQUERQUE for free if someone wants to pick them up (they are too heavy for me anymore). They are great for glow discharge cleaning or basic sputter deposition. They are AS IS WHERE IS!!!!
?
***
I have had the following inquiry about some aluminum coating if someone wants to help the guy.
Thanks for taking a minute on the phone to discuss my coating need. ?I have a project that I am in need of some help in the way of coating some thin polycarbonate films. I have a very limited budget to work with. I am hoping to find someone to do a run for as little money as possible. The product should result in follow on work that will support paying full price on future runs. I need 1500 angstroms of aluminum coated on to some polymer films that are in the 1 micron thickness range and about 1" x 3" in size. They are free standing films that are mounted in frames. I can machine all of the hanging fixtures and I would also be willing to trade machine work in exchange for doing a coating run. I need to just get the proof of specification ?samples in the customers hands to get positioned where I will be getting ?follow on orders.
?
I appreciate anything you can do to find someone willing and able to help.
?
Thanks,
?
Dan Petmecky
TMI
****
Don
Don,
I don't have the ability to shutter all the coils so can you describe what a cleaning with an oxidizing agent would be ???
Are you describing a final cleaning of the coils with a spray with hydrogen peroxide ( household variety ) or a brushing on of a bleach solution ????
I was wondering if I could use a propane torch to locally heat the coils and wick the aluminum onto them before I close up the chamber.? Have you ever tried this kind of pre-wet of tungsten ???? Removing the coils from the holders can be done but it usually results in a broken coil.?
Thanks
Drew in soggy Florida
-----------------------------------------------------------------------------------------------------------
On Mon, Sep 26, 2011 at 11:11 PM, SVC <donmattox@...> wrote:
?
When heating tungsten filaments to evaporate aluminum the first thing that is vaporized is the tungsten oxide. This is why you either need to strip the oxide off (electropolising or by chemical cleaning using an oxidizing agent) before heating or you should use a shutter (closed while premelting the aluminum on the tungsten).? The aluminum will melt and wet the tungsten at temperatures way below what is needed to evaporate the aluminum. When the temperature is increased the aluminum will evaporate Then open the shutter).? Don
Precisely!
?
Guy Brandenburg, Washington, DC?
============================
From: Andrew Aurigema <eosraptor@...>
To: VacuumX@...
Sent: Monday, September 26, 2011 4:44 PM
Subject: Re: [VacuumX] Al sticking, Cr sticking, Cr stripping
?
thanks for the tip.? So slowly on the current so the coils have a chance to heat up the aluminum and never got to bright glow till they are aluminum coated.?
On Mon, Sep 26, 2011 at 4:03 PM, Guy Brandenburg <gfbrandenburg@...> wrote:
?
Andrew, Try ramping up the current and voltage very slowly on your tungsten filament in the future. Take nearly a minute to reach full current.
It worked for me; it might possibly work for you.
Guy
On Sep 26, 2011, at 3:08 PM, Andrew Aurigema <eosraptor@...> wrote:
?
That is very clever actually.? Reverse electro plating.?
I too ran into overly stuck on coatings this weekend.? I almost have my chamber back up and working but the pressure is still a little to high.? When I strip the coating off there is a thin film of dark looking soot on the glass.? This will not "green river" strip off.? In fact nothing took it off.? I was forced to set back up the polishing lap and do another 20 minutes of automated figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the first coils.? The tungsten is bright red / near white hot for a few seconds while the aluminum is melting and wicking up onto it.? In that time, the tungsten "burns" if the pressure is a little high.? That black film is now under the aluminum.? It is great for adhesion but taking it off is not possible without
polishing.?
It may be possible to use this mistake somehow.? Maybe set up one tungsten in the center of the chamber that you burn for 10 seconds at a pressure not quite as low as for coatings.? If there is no aluminum on the tungsten then it will burn and make that tungsten soot.? Aluminizing over that soot stuff is a sure fire way to get the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if somebody is bored out there.????
Just remember, to get that film off you will be using CeO and pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning cathode
as he described in his pdf file. And it seems the Al passed mostly the tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the Al tn a piece of glass. And sticked very well. Later I was able to strip them by green river.
So that is why Sunday I started to make some good coating for mirrors. Four of them was loaded and coated first 20nm Cr and than 120nm Al, and before I could coat the two oxide layer I had to terminate the process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed. But this time the Cr sticked so well the green river was not able to strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was able to
strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery acid), a lead plate for the negative and a sponge on the positive electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite?
__._,_.__
--
____________________________________ Donald M. Mattox Society of Vacuum Coaters 71 Pinon Hill Place NE Albuquerque, NM? 87122-1914 Telephone 505/856-7188FAX 505/856-6716E-mail donmattox@...WebSite?
|
Re: Evaporating aluminum from tungsten (or tantalum)
Don,
I am always looking for vac feed thru.? May I inquire what fittings you have ???
Pre-melting the aluminum in vacuum in a separate vacuum run is just too much effort.? I have to let my chamber sit under vacuum for 12 hrs to de-gas or it takes forever to pump down.? So I think I will pre-melt all the emitters before I evaporate any of them.? The tips you ( and others ) have given me are very useful.?
I can heat the tungsten coils up to the aluminum melting / wicking point slowly and then shut them down and move on to the next group to do the same.?? After all of them are wetted out, I can run them at high power to do the depositon.? I have an old XMS-1 thickness meter that clearly shows the nanometer per second deposition rate.? I usually see around 15 nm / second deposition rate with a full coil of aluminum and the deposition rate drops off fast after 10 seconds of power.? That is about how long the aluminum last on the coils.?
Hopefully a new procedure will reduce my tungsten oxide "soot" problem to just an annoying under layer that is covered by shiny aluminum.?
I always fire my center coils last and shut them down early so the final layer of aluminum is as shiny as I can make it.? 5 years into vacuum coating and I still am not very proficient at? it.? Good thing I kept my day job :_))))))
Thanks again,
Drew in soggy Florida
?-------------------------------------------------------------------------------------------------------------
toggle quoted message
Show quoted text
On Tue, Sep 27, 2011 at 9:39 AM, SVC <donmattox@...> wrote:
?
Good point!! I left out the use of
premelting the aluminum on the tungsten by heating it in vaciuum WITH
NO SUBSTRATE in place.? Then open the chamber and mount the
substrate - coat. I didn't think of this because it is obviously labor
intensive. They use to sell prewetted filaments but I guess it wasn't
profitable. If you use an evaporate-to-completion technique you can
weigh the filament - prewet the tungsten with a small amount of
aluminum then add enough Al to do the job. Aluminum will not evaporate
much at its melting point.
Tungsten coils break because they crystallize on heating and
become brittle. Limiting heating (and time) makes the coils last
longer.
A general problem with evaporation from a filament or boat is
that the evaporant is initally in poor thermal contact with the heated
surface and so there is a tendency to over-heat the tungsten and as
the aluminum melts, it spreads over the very hot surface and tends to
spatter. Heat the filament slowly!! until the aluminum melts. Again -
pre-cleaning the tungsten aids in wetting.
To clean the tungsten you can heat it in
CLOROX on the stove.
DO NOT heat the tungsten/aluminum in air with a torch - you will only
create a mess!
I have a bunch of evaporating filaments and vacuum chamber
feedthroughs that I will part with if anyone has a particular
need.
I also have two old (thyraton rectifier) high voltage (up to 5000
VDC) power supplies (no arc suppression) in ALBUQUERQUE for free if
someone wants to pick them up (they are too heavy for me anymore).
They are great for glow discharge cleaning or basic sputter
deposition. They are AS IS WHERE IS!!!!
?
***
I have had the following inquiry about some aluminum coating if
someone wants to help the guy.
Thanks for taking a minute on the phone
to discuss my coating need. ?I have a project that I am in need
of some help in the way of coating some thin polycarbonate films. I
have a very limited budget to work with. I am hoping to find someone
to do a run for as little money as possible. The product should result
in follow on work that will support paying full price on future runs.
I need 1500 angstroms of aluminum coated on to some polymer films that
are in the 1 micron thickness range and about 1" x 3" in size.
They are free standing films that are mounted in frames. I can machine
all of the hanging fixtures and I would also be willing to trade
machine work in exchange for doing a coating run. I need to just get
the proof of specification ?samples in the customers hands to get
positioned where I will be getting ?follow on
orders.
?
I appreciate anything you can do to find
someone willing and able to help.
?
Thanks,
?
Dan Petmecky
TMI
****
Don
Don,
I don't have the ability to shutter all the coils so can you describe
what a cleaning with an oxidizing agent would be ???
Are you describing a final cleaning of the coils with a spray with
hydrogen peroxide ( household variety ) or a brushing on of a bleach
solution ????
I was wondering if I could use a propane torch to locally heat the
coils and wick the aluminum onto them before I close up the chamber.?
Have you ever tried this kind of pre-wet of tungsten ????
Removing the coils from the holders can be done but it usually results
in a broken coil.?
Thanks
Drew in soggy Florida
-----------------------------------------------------------------------------------------------------------
On Mon, Sep 26, 2011 at 11:11 PM, SVC <donmattox@...> wrote:
?
When heating tungsten filaments to
evaporate aluminum the first thing that is vaporized is the tungsten
oxide. This is why you either need to strip the oxide off
(electropolising or by chemical cleaning using an oxidizing agent)
before heating or you should use a shutter (closed while premelting
the aluminum on the tungsten).? The aluminum will melt and wet
the tungsten at temperatures way below what is needed to evaporate the
aluminum. When the temperature is increased the aluminum will
evaporate Then open the shutter).? Don
Precisely!
?
Guy Brandenburg, Washington, DC?
============================
From: Andrew Aurigema
<eosraptor@...>
To: VacuumX@...
Sent: Monday, September 26, 2011 4:44 PM
Subject: Re: [VacuumX] Al sticking, Cr sticking, Cr
stripping
?
thanks for the tip.? So slowly on the current so the
coils have a chance to heat up the aluminum and never got to bright
glow till they are aluminum coated.?
On Mon, Sep 26, 2011 at 4:03 PM, Guy Brandenburg <gfbrandenburg@...>
wrote:
?
Andrew, Try ramping up the current and voltage very slowly
on your tungsten filament in the future. Take nearly a minute to reach
full current.
It worked for me; it might possibly work for
you.
Guy
On Sep 26, 2011, at 3:08 PM, Andrew Aurigema <eosraptor@...>
wrote:
?
That is very clever actually.? Reverse electro
plating.?
I too ran into overly stuck on coatings this weekend.? I almost
have my chamber back up and working but the pressure is still a little
to high.? When I strip the coating off there is a thin film of
dark looking soot on the glass.? This will not "green river"
strip off.? In fact nothing took it off.? I was forced to
set back up the polishing lap and do another 20 minutes of automated
figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the
first coils.? The tungsten is bright red / near white hot for a
few seconds while the aluminum is melting and wicking up onto it.?
In that time, the tungsten "burns" if the pressure is a
little high.? That black film is now under the aluminum.? It
is great for adhesion but taking it off is not possible without
polishing.?
It may be possible to use this mistake somehow.? Maybe set up one
tungsten in the center of the chamber that you burn for 10 seconds at
a pressure not quite as low as for coatings.? If there is no
aluminum on the tungsten then it will burn and make that tungsten
soot.? Aluminizing over that soot stuff is a sure fire way to get
the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if
somebody is bored out there.????
Just remember, to get that film off you will be using CeO and
pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila
<schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning
cathode
as he described in his pdf file. And it seems the Al passed mostly the
tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the
Al tn a piece of glass. And sticked very well. Later I was able to
strip them by green river.
So that is why Sunday I started to make some good coating for mirrors.
Four of them was loaded and coated first 20nm Cr and than 120nm Al,
and before I could coat the two oxide layer I had to terminate the
process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed.
But this time the Cr sticked so well the green river was not able to
strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was
able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery
acid), a lead plate for the negative and a sponge on the positive
electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr
solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite?
__._,_.__
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite?
|
Re: Evaporating aluminum from tungsten (or tantalum)
Good point!! I left out the use of
premelting the aluminum on the tungsten by heating it in vaciuum WITH
NO SUBSTRATE in place.? Then open the chamber and mount the
substrate - coat. I didn't think of this because it is obviously labor
intensive. They use to sell prewetted filaments but I guess it wasn't
profitable. If you use an evaporate-to-completion technique you can
weigh the filament - prewet the tungsten with a small amount of
aluminum then add enough Al to do the job. Aluminum will not evaporate
much at its melting point.
Tungsten coils break because they crystallize on heating and
become brittle. Limiting heating (and time) makes the coils last
longer.
A general problem with evaporation from a filament or boat is
that the evaporant is initally in poor thermal contact with the heated
surface and so there is a tendency to over-heat the tungsten and as
the aluminum melts, it spreads over the very hot surface and tends to
spatter. Heat the filament slowly!! until the aluminum melts. Again -
pre-cleaning the tungsten aids in wetting.
To clean the tungsten you can heat it in
CLOROX on the stove.
DO NOT heat the tungsten/aluminum in air with a torch - you will only
create a mess!
I have a bunch of evaporating filaments and vacuum chamber
feedthroughs that I will part with if anyone has a particular
need.
I also have two old (thyraton rectifier) high voltage (up to 5000
VDC) power supplies (no arc suppression) in ALBUQUERQUE for free if
someone wants to pick them up (they are too heavy for me anymore).
They are great for glow discharge cleaning or basic sputter
deposition. They are AS IS WHERE IS!!!!
?
***
I have had the following inquiry about some aluminum coating if
someone wants to help the guy.
Thanks for taking a minute on the phone
to discuss my coating need. ?I have a project that I am in need
of some help in the way of coating some thin polycarbonate films. I
have a very limited budget to work with. I am hoping to find someone
to do a run for as little money as possible. The product should result
in follow on work that will support paying full price on future runs.
I need 1500 angstroms of aluminum coated on to some polymer films that
are in the 1 micron thickness range and about 1" x 3" in size.
They are free standing films that are mounted in frames. I can machine
all of the hanging fixtures and I would also be willing to trade
machine work in exchange for doing a coating run. I need to just get
the proof of specification ?samples in the customers hands to get
positioned where I will be getting ?follow on
orders.
?
I appreciate anything you can do to find
someone willing and able to help.
?
Thanks,
?
Dan Petmecky
TMI
505-293-6136
dan@...
****
Don
Don,
I don't have the ability to shutter all the coils so can you describe
what a cleaning with an oxidizing agent would be ???
Are you describing a final cleaning of the coils with a spray with
hydrogen peroxide ( household variety ) or a brushing on of a bleach
solution ????
I was wondering if I could use a propane torch to locally heat the
coils and wick the aluminum onto them before I close up the chamber.?
Have you ever tried this kind of pre-wet of tungsten ????
Removing the coils from the holders can be done but it usually results
in a broken coil.?
Thanks
Drew in soggy Florida
-----------------------------------------------------------------------------------------------------------
On Mon, Sep 26, 2011 at 11:11 PM, SVC <donmattox@...> wrote:
?
When heating tungsten filaments to
evaporate aluminum the first thing that is vaporized is the tungsten
oxide. This is why you either need to strip the oxide off
(electropolising or by chemical cleaning using an oxidizing agent)
before heating or you should use a shutter (closed while premelting
the aluminum on the tungsten).? The aluminum will melt and wet
the tungsten at temperatures way below what is needed to evaporate the
aluminum. When the temperature is increased the aluminum will
evaporate Then open the shutter).? Don
Precisely!
?
Guy Brandenburg, Washington, DC?
============================
From: Andrew Aurigema
<eosraptor@...>
To: VacuumX@...
Sent: Monday, September 26, 2011 4:44 PM
Subject: Re: [VacuumX] Al sticking, Cr sticking, Cr
stripping
?
thanks for the tip.? So slowly on the current so the
coils have a chance to heat up the aluminum and never got to bright
glow till they are aluminum coated.?
On Mon, Sep 26, 2011 at 4:03 PM, Guy Brandenburg <gfbrandenburg@...>
wrote:
?
Andrew, Try ramping up the current and voltage very slowly
on your tungsten filament in the future. Take nearly a minute to reach
full current.
It worked for me; it might possibly work for
you.
Guy
On Sep 26, 2011, at 3:08 PM, Andrew Aurigema <eosraptor@...>
wrote:
?
That is very clever actually.? Reverse electro
plating.?
I too ran into overly stuck on coatings this weekend.? I almost
have my chamber back up and working but the pressure is still a little
to high.? When I strip the coating off there is a thin film of
dark looking soot on the glass.? This will not "green river"
strip off.? In fact nothing took it off.? I was forced to
set back up the polishing lap and do another 20 minutes of automated
figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the
first coils.? The tungsten is bright red / near white hot for a
few seconds while the aluminum is melting and wicking up onto it.?
In that time, the tungsten "burns" if the pressure is a
little high.? That black film is now under the aluminum.? It
is great for adhesion but taking it off is not possible without
polishing.?
It may be possible to use this mistake somehow.? Maybe set up one
tungsten in the center of the chamber that you burn for 10 seconds at
a pressure not quite as low as for coatings.? If there is no
aluminum on the tungsten then it will burn and make that tungsten
soot.? Aluminizing over that soot stuff is a sure fire way to get
the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if
somebody is bored out there.????
Just remember, to get that film off you will be using CeO and
pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila
wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning
cathode
as he described in his pdf file. And it seems the Al passed mostly the
tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the
Al tn a piece of glass. And sticked very well. Later I was able to
strip them by green river.
So that is why Sunday I started to make some good coating for mirrors.
Four of them was loaded and coated first 20nm Cr and than 120nm Al,
and before I could coat the two oxide layer I had to terminate the
process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed.
But this time the Cr sticked so well the green river was not able to
strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was
able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery
acid), a lead plate for the negative and a sponge on the positive
electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr
solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite?
__._,_.__
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite? http://www.svc.org
|
Re: Evaporating aluminum from tungsten (or tantalum)
Don,
I don't have the ability to shutter all the coils so can you describe what a cleaning with an oxidizing agent would be ???
Are you describing a final cleaning of the coils with a spray with hydrogen peroxide ( household variety ) or a brushing on of a bleach solution ????
I was wondering if I could use a propane torch to locally heat the coils and wick the aluminum onto them before I close up the chamber.? Have you ever tried this kind of pre-wet of tungsten ???? Removing the coils from the holders can be done but it usually results in a broken coil.?
Thanks
Drew in soggy Florida
-----------------------------------------------------------------------------------------------------------
toggle quoted message
Show quoted text
On Mon, Sep 26, 2011 at 11:11 PM, SVC <donmattox@...> wrote:
?
When heating tungsten filaments to
evaporate aluminum the first thing that is vaporized is the tungsten
oxide. This is why you either need to strip the oxide off
(electropolising or by chemical cleaning using an oxidizing agent)
before heating or you should use a shutter (closed while premelting
the aluminum on the tungsten).? The aluminum will melt and wet
the tungsten at temperatures way below what is needed to evaporate the
aluminum. When the temperature is increased the aluminum will
evaporate Then open the shutter).? Don
Precisely!
?
Guy Brandenburg, Washington, DC?
============================
From:
Andrew Aurigema <eosraptor@...>
To: VacuumX@...
Sent: Monday, September 26, 2011 4:44 PM
Subject: Re: [VacuumX] Al sticking, Cr sticking, Cr
stripping
?
thanks for the tip.? So slowly on
the current so the coils have a chance to heat up the aluminum and
never got to bright glow till they are aluminum coated.?
On Mon, Sep 26, 2011 at 4:03 PM, Guy
Brandenburg <gfbrandenburg@...>
wrote:
?
Andrew, Try ramping up the current and voltage very slowly
on your tungsten filament in the future. Take nearly a minute to reach
full current.
It worked for me; it might possibly work for you.
Guy
On Sep 26, 2011, at 3:08 PM, Andrew Aurigema <eosraptor@...>
wrote:
?
That is very clever actually.? Reverse electro
plating.?
I too ran into overly stuck on coatings this weekend.? I almost
have my chamber back up and working but the pressure is still a little
to high.? When I strip the coating off there is a thin film of
dark looking soot on the glass.? This will not "green river"
strip off.? In fact nothing took it off.? I was forced to
set back up the polishing lap and do another 20 minutes of automated
figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the
first coils.? The tungsten is bright red / near white hot for a
few seconds while the aluminum is melting and wicking up onto it.?
In that time, the tungsten "burns" if the pressure is a
little high.? That black film is now under the aluminum.? It
is great for adhesion but taking it off is not possible without
polishing.?
It may be possible to use this mistake somehow.? Maybe set up one
tungsten in the center of the chamber that you burn for 10 seconds at
a pressure not quite as low as for coatings.? If there is no
aluminum on the tungsten then it will burn and make that tungsten
soot.? Aluminizing over that soot stuff is a sure fire way to get
the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if
somebody is bored out there.????
Just remember, to get that film off you will be using CeO and
pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning
cathode
as he described in his pdf file. And it seems the Al passed mostly the
tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the
Al tn a piece of glass. And sticked very well. Later I was able to
strip them by green river.
So that is why Sunday I started to make some good coating for mirrors.
Four of them was loaded and coated first 20nm Cr and than 120nm Al,
and before I could coat the two oxide layer I had to terminate the
process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed.
But this time the Cr sticked so well the green river was not able to
strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was
able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery
acid), a lead plate for the negative and a sponge on the positive
electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr
solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite?
__._,_.__
|
Re: Evaporating aluminum from tungsten (or tantalum)
When heating tungsten filaments to
evaporate aluminum the first thing that is vaporized is the tungsten
oxide. This is why you either need to strip the oxide off
(electropolising or by chemical cleaning using an oxidizing agent)
before heating or you should use a shutter (closed while premelting
the aluminum on the tungsten).? The aluminum will melt and wet
the tungsten at temperatures way below what is needed to evaporate the
aluminum. When the temperature is increased the aluminum will
evaporate Then open the shutter).? Don
Precisely!
?
Guy Brandenburg, Washington, DC?
http://gfbrandenburg.wordpress.com/
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
============================
From:
Andrew Aurigema
To: VacuumX@...
Sent: Monday, September 26, 2011 4:44 PM
Subject: Re: [VacuumX] Al sticking, Cr sticking, Cr
stripping
?
thanks for the tip.? So slowly on
the current so the coils have a chance to heat up the aluminum and
never got to bright glow till they are aluminum coated.?
On Mon, Sep 26, 2011 at 4:03 PM, Guy
Brandenburg <gfbrandenburg@...>
wrote:
?
Andrew, Try ramping up the current and voltage very slowly
on your tungsten filament in the future. Take nearly a minute to reach
full current.
It worked for me; it might possibly work for you.
Guy
On Sep 26, 2011, at 3:08 PM, Andrew Aurigema <eosraptor@...>
wrote:
?
That is very clever actually.? Reverse electro
plating.?
I too ran into overly stuck on coatings this weekend.? I almost
have my chamber back up and working but the pressure is still a little
to high.? When I strip the coating off there is a thin film of
dark looking soot on the glass.? This will not "green river"
strip off.? In fact nothing took it off.? I was forced to
set back up the polishing lap and do another 20 minutes of automated
figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the
first coils.? The tungsten is bright red / near white hot for a
few seconds while the aluminum is melting and wicking up onto it.?
In that time, the tungsten "burns" if the pressure is a
little high.? That black film is now under the aluminum.? It
is great for adhesion but taking it off is not possible without
polishing.?
It may be possible to use this mistake somehow.? Maybe set up one
tungsten in the center of the chamber that you burn for 10 seconds at
a pressure not quite as low as for coatings.? If there is no
aluminum on the tungsten then it will burn and make that tungsten
soot.? Aluminizing over that soot stuff is a sure fire way to get
the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if
somebody is bored out there.????
Just remember, to get that film off you will be using CeO and
pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning
cathode
as he described in his pdf file. And it seems the Al passed mostly the
tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the
Al tn a piece of glass. And sticked very well. Later I was able to
strip them by green river.
So that is why Sunday I started to make some good coating for mirrors.
Four of them was loaded and coated first 20nm Cr and than 120nm Al,
and before I could coat the two oxide layer I had to terminate the
process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed.
But this time the Cr sticked so well the green river was not able to
strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was
able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery
acid), a lead plate for the negative and a sponge on the positive
electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr
solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
--
____________________________________
Donald M. Mattox
Society of Vacuum Coaters
71 Pinon Hill Place NE
Albuquerque, NM? 87122-1914
Telephone 505/856-7188
FAX 505/856-6716
E-mail donmattox@...
WebSite? http://www.svc.org
|
Re: Al sticking, Cr sticking, Cr stripping
Precisely! ? Guy Brandenburg, Washington, DC?
http://gfbrandenburg.wordpress.com/
http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
============================
From: Andrew Aurigema
To: VacuumX@...
Sent: Monday, September 26, 2011 4:44 PM
Subject: Re: [VacuumX] Al sticking, Cr sticking, Cr
stripping
?
thanks for the tip.? So slowly on the current so the coils have a chance to heat up the aluminum and never got to bright glow till they are aluminum coated.?
On Mon, Sep 26, 2011 at 4:03 PM, Guy Brandenburg <gfbrandenburg@...> wrote:
?
Andrew, Try ramping up the current and voltage very slowly on your tungsten filament in the future. Take nearly a minute to reach full current. It worked for me; it might possibly work for you.
Guy On Sep 26, 2011, at 3:08 PM, Andrew Aurigema < eosraptor@...> wrote:
?
That is very clever actually.? Reverse electro plating.?
I too ran into overly stuck on coatings this weekend.? I almost have my chamber back up and working but the pressure is still a little to high.? When I strip the coating off there is a thin film of dark looking soot on the glass.? This will not "green river" strip off.? In fact nothing took it off.? I was forced to set back up the polishing lap and do another 20 minutes of automated figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the first coils.? The tungsten is bright red / near white hot for a few seconds while the aluminum is melting and wicking up onto it.? In that time, the tungsten "burns" if the pressure is a little high.? That black film is now under the aluminum.? It is great for adhesion but taking it off is not possible without polishing.?
It may be possible to use this mistake somehow.? Maybe set up one tungsten in the center of the chamber that you burn for 10 seconds at a pressure not quite as low as for coatings.? If there is no aluminum on the tungsten then it will burn and make that tungsten soot.? Aluminizing over that soot stuff is a sure fire way to get the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if somebody is bored out there.????
Just remember, to get that film off you will be using CeO and pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning cathode
as he described in his pdf file. And it seems the Al passed mostly the tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the Al tn a piece of glass. And sticked very well. Later I was able to strip them by green river.
So that is why Sunday I started to make some good coating for mirrors. Four of them was loaded and coated first 20nm Cr and than 120nm Al, and before I could coat the two oxide layer I had to terminate the process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed. But this time the Cr sticked so well the green river was not able to strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery acid), a lead plate for the negative and a sponge on the positive electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
|
Re: Al sticking, Cr sticking, Cr stripping
thanks for the tip.? So slowly on the current so the coils have a chance to heat up the aluminum and never got to bright glow till they are aluminum coated.?
toggle quoted message
Show quoted text
On Mon, Sep 26, 2011 at 4:03 PM, Guy Brandenburg <gfbrandenburg@...> wrote:
?
Andrew, Try ramping up the current and voltage very slowly on your tungsten filament in the future. Take nearly a minute to reach full current. It worked for me; it might possibly work for you.
Guy On Sep 26, 2011, at 3:08 PM, Andrew Aurigema < eosraptor@...> wrote:
?
That is very clever actually.? Reverse electro plating.?
I too ran into overly stuck on coatings this weekend.? I almost have my chamber back up and working but the pressure is still a little to high.? When I strip the coating off there is a thin film of dark looking soot on the glass.? This will not "green river" strip off.? In fact nothing took it off.? I was forced to set back up the polishing lap and do another 20 minutes of automated figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the first coils.? The tungsten is bright red / near white hot for a few seconds while the aluminum is melting and wicking up onto it.? In that time, the tungsten "burns" if the pressure is a little high.? That black film is now under the aluminum.? It is great for adhesion but taking it off is not possible without polishing.?
It may be possible to use this mistake somehow.? Maybe set up one tungsten in the center of the chamber that you burn for 10 seconds at a pressure not quite as low as for coatings.? If there is no aluminum on the tungsten then it will burn and make that tungsten soot.? Aluminizing over that soot stuff is a sure fire way to get the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if somebody is bored out there.????
Just remember, to get that film off you will be using CeO and pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning cathode
as he described in his pdf file. And it seems the Al passed mostly the tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the Al tn a piece of glass. And sticked very well. Later I was able to strip them by green river.
So that is why Sunday I started to make some good coating for mirrors. Four of them was loaded and coated first 20nm Cr and than 120nm Al, and before I could coat the two oxide layer I had to terminate the process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed. But this time the Cr sticked so well the green river was not able to strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery acid), a lead plate for the negative and a sponge on the positive electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
|
Re: Al sticking, Cr sticking, Cr stripping
Andrew, Try ramping up the current and voltage very slowly on your tungsten filament in the future. Take nearly a minute to reach full current. It worked for me; it might possibly work for you.
Guy
On Sep 26, 2011, at 3:08 PM, Andrew Aurigema < eosraptor@...> wrote:
?
That is very clever actually.? Reverse electro plating.?
I too ran into overly stuck on coatings this weekend.? I almost have my chamber back up and working but the pressure is still a little to high.? When I strip the coating off there is a thin film of dark looking soot on the glass.? This will not "green river" strip off.? In fact nothing took it off.? I was forced to set back up the polishing lap and do another 20 minutes of automated figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the first coils.? The tungsten is bright red / near white hot for a few seconds while the aluminum is melting and wicking up onto it.? In that time, the tungsten "burns" if the pressure is a little high.? That black film is now under the aluminum.? It is great for adhesion but taking it off is not possible without polishing.?
It may be possible to use this mistake somehow.? Maybe set up one tungsten in the center of the chamber that you burn for 10 seconds at a pressure not quite as low as for coatings.? If there is no aluminum on the tungsten then it will burn and make that tungsten soot.? Aluminizing over that soot stuff is a sure fire way to get the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if somebody is bored out there.????
Just remember, to get that film off you will be using CeO and pitch.
Drew in soggy Florida
---------------------------------------------------------------------
On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning cathode
as he described in his pdf file. And it seems the Al passed mostly the tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the Al tn a piece of glass. And sticked very well. Later I was able to strip them by green river.
So that is why Sunday I started to make some good coating for mirrors. Four of them was loaded and coated first 20nm Cr and than 120nm Al, and before I could coat the two oxide layer I had to terminate the process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed. But this time the Cr sticked so well the green river was not able to strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery acid), a lead plate for the negative and a sponge on the positive electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
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Re: Al sticking, Cr sticking, Cr stripping
That is very clever actually.? Reverse electro plating.?
I too ran into overly stuck on coatings this weekend.? I almost have my chamber back up and working but the pressure is still a little to high.? When I strip the coating off there is a thin film of dark looking soot on the glass.? This will not "green river" strip off.? In fact nothing took it off.? I was forced to set back up the polishing lap and do another 20 minutes of automated figuring to fully remove the film.?
I am thinking that the problem is the first few seconds of heat to the first coils.? The tungsten is bright red / near white hot for a few seconds while the aluminum is melting and wicking up onto it.? In that time, the tungsten "burns" if the pressure is a little high.? That black film is now under the aluminum.? It is great for adhesion but taking it off is not possible without polishing.?
It may be possible to use this mistake somehow.? Maybe set up one tungsten in the center of the chamber that you burn for 10 seconds at a pressure not quite as low as for coatings.? If there is no aluminum on the tungsten then it will burn and make that tungsten soot.? Aluminizing over that soot stuff is a sure fire way to get the aluminum to stick to the glass.?
I dont know if any of this is any good but it may be worth a look if somebody is bored out there.????
Just remember, to get that film off you will be using CeO and pitch.
Drew in soggy Florida
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On Mon, Sep 26, 2011 at 1:54 PM, Attila <schneyolo@...> wrote:
?
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning cathode
as he described in his pdf file. And it seems the Al passed mostly the tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the Al tn a piece of glass. And sticked very well. Later I was able to strip them by green river.
So that is why Sunday I started to make some good coating for mirrors. Four of them was loaded and coated first 20nm Cr and than 120nm Al, and before I could coat the two oxide layer I had to terminate the process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed. But this time the Cr sticked so well the green river was not able to strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery acid), a lead plate for the negative and a sponge on the positive electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
__._,_.
|
Al sticking, Cr sticking, Cr stripping
Hi All,
I just would like to share some experience about these.
Thank's for Vladimir I made the triangle glow discharge cleaning cathode
as he described in his pdf file. And it seems the Al passed mostly the tape test.
But just in case I tried to evapaorate 10nm Cr at 1,5nm/sec under the Al tn a piece of glass. And sticked very well. Later I was able to strip them by green river.
So that is why Sunday I started to make some good coating for mirrors. Four of them was loaded and coated first 20nm Cr and than 120nm Al, and before I could coat the two oxide layer I had to terminate the process because of the shutter failure.
No problem , let's strip off the Cr and Al by green river I guessed. But this time the Cr sticked so well the green river was not able to strip it.
I have no HF acid. So I tried everything without succes.
Suddenly I found an idea and tried it. And this one worked and I was able to strip off the Cr easily without eching the glass.
The methode is the reverse electroplating. I used sulphur acid(battery acid), a lead plate for the negative and a sponge on the positive electrode. The power supply was my inverting welder.
As I rubbed the surface of the immersed mirror the Cr solved and I was able to whipe it off.
So at least for 20nm Cr it works.
Have a nice day!
Br.
Attila
|
Diffusion pump pumping speed up
Hi!
I put a file to the files section diffusion pump. This is an invention what I accomplished on the last week.
The main problem was with my DP, its pumping speed was low 220l/sec. Not enough to operate the ion source and the ebeam gun in the same time(IBAD). I put photos from the modification I have made, in my photo album.
The bulged part was turned on the lathe from two solid pieces. Than TIG welded from the inside into the old pump. The nozzle tower is the same. On the outside I soldered a soft copper pipe 8mm diam, for the cooling. The original 750W heating changed to 1500W. I use Apiezon AP201 oil now. But only for try, later I am going to change to Santovac 5
I put 250ccm from the AP201 into, than it was vacuumised for two hours. Than I turned on the cooling and heating, and with closed plate valve vacuumise for another 5 hours, because of outgassing.Then shut down.
Next day I turned on, and vacuumised for 4 hours, but now with opened plate valve.
The base pressure was easily achieved 2x10-5 Torr. After this I opened the needle valve and let Argon into the chamber. In the same time I checked the vacuum gauge. The differet was obvious. Opening the valve same amount as before the pressure was lower. It could tolerate higher gas load than before.
I can't measure the pumping speed, but this is now enough to operate the ion source too.
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New file uploaded to VacuumX
Hello,
This email message is a notification to let you know that
a file has been uploaded to the Files area of the VacuumX
group.
File : /Diffussion pump/US3363830.pdf
Uploaded by : schneyolo <schneyolo@...>
Description : Diffusion pump
You can access this file at the URL:
To learn more about file sharing for your group, please visit:
Regards,
schneyolo <schneyolo@...>
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Attila,
I absolutely agree with Don Mattox - nothing to add... Just be also careful with HF!!...:-)
Regards,
Vladimir
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On 9/16/2011 6:47 AM, Attila wrote: Valdimir!
How can you strip off the Chrome from the glass?
In my experience, it comes off by polishing with pich or by grinding. I have not find any soultion which solves the Cr underlayer.
Br.
Attila
--- In VacuumX@..., Vladimir Chutko<chutko@...> wrote:
For Al and Ag I deposit 300 A Cr underlayer on glass at 20 A/s . Before
I make oxygen ion beam substrates pre-cleaning during 2-3 min.
Everything looks fine, adhesion is very good.
Vladimir Chutko
On 9/13/2011 7:17 PM, pjifl@... wrote:
I need to do Cr coating which must adhere very well. But my evaporation
rate may not be as high as I would like.
Cr is always mentioned as holding on to glass well - better than most other
metals.
But, after reading how evaporation rate influences the sticking of Al on
glass, how important is it for Cr ?
Peter Smith
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