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Re: [VacuumX] Useing nickle in tungsten boat

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  • Guy Brandenburg
    Roger, that s a pretty good vacuum, IMO, not that I m any kind of expert. Why are you attempting to coat with copper? What is it like when you use silver? Guy
    Message 1 of 8 , Apr 1, 2010
      Roger, that's a pretty good vacuum, IMO, not that I'm any kind of expert.
      Why are you attempting to coat with copper?
      What is it like when you use silver?

      Guy Brandenburg, Washington, DC 

      My blog, mostly on Education in DC:
      http://gfbrandenburg.wordpress.com/

      My home page on astronomy, mathematics, education:
      http://home.earthlink.net/~gfbranden/GFB_Home_Page.html
      or else   
      http://tinyurl.com/r6fh2
      =====================================

      --- On Wed, 3/31/10, sciotoa <sciotoa@...> wrote:

      From: sciotoa <sciotoa@...>
      Subject: [VacuumX] Useing nickle in tungsten boat
      To: vacuumx@yahoogroups.com
      Date: Wednesday, March 31, 2010, 9:27 PM

       

      I'm kind of new to this stuff. so far I have successfully coated with copper and silver but If I try nickle in a tungsten boat, the bottom just gets melted out of the boat. Everything I have read indicates that it should work but I must be doing something wrong. In case it matters, the vacuum I am using is somewhere between 1x10-5 and 7x10-6 torr.

      Roger


    • toglman
      Roger, This is not unusual at all. Nickel is very aggressive to the refractory metals at elevated temperatures. Copper and silver are not. The only issue
      Message 2 of 8 , Apr 1, 2010
        Roger,

        This is not unusual at all. Nickel is very aggressive to the refractory metals at elevated temperatures. Copper and silver are not. The only issue with silver is that it does not wet tungsten very well, so molybdenum is sometimes used as a source instead.

        If you have the power available, I'd suggest a thicker tungsten boat for your nickel evaporation. Another possibility would be to use a tungsten boat that has been coated with alumina.

        Best,

        Kevin

        --- In VacuumX@yahoogroups.com, "sciotoa" <sciotoa@...> wrote:
        >
        > I'm kind of new to this stuff. so far I have successfully coated with copper and silver but If I try nickle in a tungsten boat, the bottom just gets melted out of the boat. Everything I have read indicates that it should work but I must be doing something wrong. In case it matters, the vacuum I am using is somewhere between 1x10-5 and 7x10-6 torr.
        >
        > Roger
        >
      • sciotoa
        Thanks for the suggestions. The coater I have was given to me by Bill Pollack who has posted here before as Arcstarter. It was originally used for coating
        Message 3 of 8 , Apr 1, 2010
          Thanks for the suggestions. The coater I have was given to me by Bill Pollack who has posted here before as Arcstarter. It was originally used for coating quarts crystals used in electronic oscillators.
          It would first coat a layer of nickle and then a layer of gold on top of that. So far I have just been coating stuff just so I can learn how it works.

          The machine is made to use two boats with a separate transformer for each. I was wondering why one transformer was a lot bigger than the other. The bigger one may be for the nickle side. The tungsten boat I was using was .01" thick. Trying a thicker one sounds like a good Idea.

          Roger



          --- In VacuumX@yahoogroups.com, "toglman" <inky@...> wrote:
          >
          > Roger,
          >
          > This is not unusual at all. Nickel is very aggressive to the refractory metals at elevated temperatures. Copper and silver are not. The only issue with silver is that it does not wet tungsten very well, so molybdenum is sometimes used as a source instead.
          >
          > If you have the power available, I'd suggest a thicker tungsten boat for your nickel evaporation. Another possibility would be to use a tungsten boat that has been coated with alumina.
          >
          > Best,
          >
          > Kevin
          >
          > --- In VacuumX@yahoogroups.com, "sciotoa" <sciotoa@> wrote:
          > >
          > > I'm kind of new to this stuff. so far I have successfully coated with copper and silver but If I try nickle in a tungsten boat, the bottom just gets melted out of the boat. Everything I have read indicates that it should work but I must be doing something wrong. In case it matters, the vacuum I am using is somewhere between 1x10-5 and 7x10-6 torr.
          > >
          > > Roger
          > >
          >
        • henry_3507
          Isnt there any risk that the tungsten would be disolved into the nickel so it would be a deposit of both? It might not matter perhaps just wanted to mention it
          Message 4 of 8 , Apr 3, 2010
            Isnt there any risk that the tungsten would be disolved into the nickel so it would be a deposit of both? It might not matter perhaps just wanted to mention it if this now micht be the case.

            Regards Henry



            --- In VacuumX@yahoogroups.com, "sciotoa" <sciotoa@...> wrote:
            >
            > Thanks for the suggestions. The coater I have was given to me by Bill Pollack who has posted here before as Arcstarter. It was originally used for coating quarts crystals used in electronic oscillators.
            > It would first coat a layer of nickle and then a layer of gold on top of that. So far I have just been coating stuff just so I can learn how it works.
            >
            > The machine is made to use two boats with a separate transformer for each. I was wondering why one transformer was a lot bigger than the other. The bigger one may be for the nickle side. The tungsten boat I was using was .01" thick. Trying a thicker one sounds like a good Idea.
          • sciotoa
            Hi Henry, That is very possible. The nickel has a high melting point and by the time it melts in the boat everything is very hot. Once it did melt it was
            Message 5 of 8 , Apr 4, 2010
              Hi Henry, That is very possible. The nickel has a high melting point and by the time it melts in the boat everything is very hot. Once it did melt it was only a mater of seconds before the boat melted down and there was a little bit of a black film all over everything.

              Roger

              --- In VacuumX@yahoogroups.com, "henry_3507" <kmnhij@...> wrote:
              >
              > Isnt there any risk that the tungsten would be disolved into the nickel so it would be a deposit of both? It might not matter perhaps just wanted to mention it if this now micht be the case.
              >
              > Regards Henry
              >
              >
              >
              > --- In VacuumX@yahoogroups.com, "sciotoa" <sciotoa@> wrote:
              > >
              > > Thanks for the suggestions. The coater I have was given to me by Bill Pollack who has posted here before as Arcstarter. It was originally used for coating quarts crystals used in electronic oscillators.
              > > It would first coat a layer of nickle and then a layer of gold on top of that. So far I have just been coating stuff just so I can learn how it works.
              > >
              > > The machine is made to use two boats with a separate transformer for each. I was wondering why one transformer was a lot bigger than the other. The bigger one may be for the nickle side. The tungsten boat I was using was .01" thick. Trying a thicker one sounds like a good Idea.
              >
            • Thomas Janstrom
              That s why Kevin at Mid Western Tungsten recommended the alumina coated tungsten boats, nickel wets tungsten a little too well shall we say.. Funny but
              Message 6 of 8 , Apr 4, 2010

                That’s why Kevin at Mid Western Tungsten recommended the alumina coated tungsten boats, nickel wets tungsten a little too well shall we say….

                 

                Funny but aluminium does this too, but the low BP means you get, in effect, fractional distillation happening leaving the W behind as the dissolved aluminium evaporates out of solution. Too much power (my best guess after much thought) and you can actually evaporate an aluminium/tungsten complex that will deposit out giving blue black coatings. Just ask Drew in Sunny (?) Florida.

                 

                Cheers, Thomas Janstrom.

                Little Gems.

                http://tjlittlegems.com

                 

                From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf Of sciotoa
                Sent: Sunday, 4 April 2010 9:54 PM
                To: VacuumX@yahoogroups.com
                Subject: [VacuumX] Re: Useing nickle in tungsten boat

                 

                 

                Hi Henry, That is very possible. The nickel has a high melting point and by the time it melts in the boat everything is very hot. Once it did melt it was only a mater of seconds before the boat melted down and there was a little bit of a black film all over everything.

                Roger

                --- In VacuumX@yahoogroups.com, "henry_3507" <kmnhij@...> wrote:

                >
                > Isnt there any risk that the tungsten would be disolved into the nickel so
                it would be a deposit of both? It might not matter perhaps just wanted to mention it if this now micht be the case.
                >
                > Regards Henry
                >
                >
                >
                > --- In VacuumX@yahoogroups.com,
                "sciotoa" <sciotoa@> wrote:
                > >
                > > Thanks for the suggestions. The coater I have was given to me by Bill
                Pollack who has posted here before as Arcstarter. It was originally used for coating quarts crystals used in electronic oscillators.
                > > It would first coat a layer of nickle and then a layer of gold on top
                of that. So far I have just been coating stuff just so I can learn how it works.
                > >
                > > The machine is made to use two boats with a separate transformer for
                each. I was wondering why one transformer was a lot bigger than the other. The bigger one may be for the nickle side. The tungsten boat I was using was .01" thick. Trying a thicker one sounds like a good Idea.
                >

              • Aurigema, Andrew N. (KSC-ASRC-491)[ASRC A
                I agree. That deep purple coating is only about 40% reflective but it is very tough. I coated my secondary a little wrong about 2 years ago and it still
                Message 7 of 8 , Apr 5, 2010

                  I agree.  That deep purple coating is only about 40% reflective but it is very tough.  I coated my secondary a little wrong about 2 years ago and it still looks perfect……. But is only 40% reflective.  So if can go less on the power and let the aluminum evaporate away the tungsten will stay behind as nasty looking crystals.

                   

                  Drew

                   

                  From: VacuumX@yahoogroups.com [mailto:VacuumX@yahoogroups.com] On Behalf Of Thomas Janstrom
                  Sent: Sunday, April 04, 2010 8:33 AM
                  To: VacuumX@yahoogroups.com
                  Subject: RE: [VacuumX] Re: Useing nickle in tungsten boat

                   

                   

                  That’s why Kevin at Mid Western Tungsten recommended the alumina coated tungsten boats, nickel wets tungsten a little too well shall we say….

                   

                  Funny but aluminium does this too, but the low BP means you get, in effect, fractional distillation happening leaving the W behind as the dissolved aluminium evaporates out of solution. Too much power (my best guess after much thought) and you can actually evaporate an aluminium/tungsten complex that will deposit out giving blue black coatings. Just ask Drew in Sunny (?) Florida.

                   

                  Cheers, Thomas Janstrom.

                  Little Gems.

                  http://tjlittlegems.com

                   

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