Titanium walls

It may be difficult to separate "theory" from "application," but let''s see if this helps facilitate the discussion.
Roberto Ferrari
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Titanium walls

Post by Roberto Ferrari » Tue Oct 09, 2018 4:08 pm

Following recent suggestion by Richard to open a discussion about the potential usefulness of titanium as the walls of the fusor chamber, here is some idea.
The cost of a full titanium chamber was mentioned as prohibitive.
A more economic alternative would be to deposit titanium onto the SS walls.
The principle of the titanium sublimation pump could be used to deposit a titanium film. 50 microns could be enough to interact with deuterons.
The setup would require a titanium filament, feed with many amps in order to start sublimation.
Having not easy way to measure the deposit, some experiments are mandatory. May be a square inch of SS exposed to the vapours under controlled parameters and then measuring it by metallographic microscopy. Surely there is some literature about Ti vacuum deposits.

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Re: Titanium walls

Post by ian_krase » Thu Oct 11, 2018 2:58 am

Sputtering Ti is also possible.

You could research Quartz Crystal deposition monitors. The detuning of a Crystal oscillator measures the mass per area.

You could also possibly measure mass loss of your Ti source with sensitive analytical balance.

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Re: Titanium walls

Post by John Futter » Thu Oct 11, 2018 6:10 am

I do sputtering all the time
both Ti and Al are very difficult due to oxidation you need vacuums in the 10^minus 8 or better to stop these oxidizing.
all can be done with a cryo pump but I have not seen this sort of system in use on this forum.

You can evaporate both of these and get reasonable results due to a much larger /quicker deposition of the required film. So for the Joe average vacuum expert like on this site I would persue evap via ebeam or standard tungsten boat /basket

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Re: Titanium walls

Post by Roberto Ferrari » Fri Oct 12, 2018 11:50 am

Ian, John thank you for your comments.
Yes, will require some additional equipment but someone will be able to do.

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Re: Titanium walls

Post by Jerry Biehler » Sat Oct 13, 2018 6:02 am

Just look at a titanium sorption pump. Basically filaments with Ti on them and the Ti evaporates on the walls and the active gasses bind with the fresh Ti and are removed from the atmosphere. So just buy some replacement filaments for these.

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Re: Titanium walls

Post by Georg Stumpf » Tue Oct 30, 2018 1:13 pm

Im interested in wich way the titanium would help in a fusor, but i can tell you that its very possible to deposit titanium. I have done so in my fist evaporation experiments and it was actually one of the best sticking metals on glass substrate i found so far. Evaporation is simply done in a molybdenum boat with high current. While it is true that it will react with the oxygen in the chamber, there is so little of it that it instantly reacts and the rest of the material will deposit very nicely.

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Re: Titanium walls

Post by Dan Knapp » Tue Oct 30, 2018 3:17 pm

Check the presentations from the recent fusion neutron sources meeting at: viewtopic.php?f=47&t=12463
The Kyoto group saw a fourfold increase in neutron production going from a stainless steel chamber to a titanium chamber. This group is one of the top IEC labs in the world, so I would guess that the fourfold increase is about the maximum one could expect from a titanium coating.

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Re: Titanium walls

Post by Frank Sanns » Fri Nov 09, 2018 4:58 am

Titanium is only one of many elements that load hydrogen. While it cannot be electroplated by conventional means, palladium can be. Early on I did some palladium plating and it was rather easy. Many companies sell plating solutions that could do the task inside of a small chamber.

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Re: Titanium walls

Post by Roberto Ferrari » Fri Nov 09, 2018 12:43 pm

Hi Frank
Of course you are right!
The thread is related to the success of Japanese researchers who improved the neutron generation when using a chamber with titanium walls. See comments by Dan Knapp and Richard.
Focusing on titanium, I suggested a cheaper way than a full titanium chamber, just depositing a titanium film on internal surface.

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Re: Titanium walls

Post by Frank Sanns » Fri Nov 09, 2018 3:45 pm

Then there is always a chamber within a chamber. Like with my larger chamber, I can put in outer grids for a variety of purposes. My usual outer grid has around 100 needle points to facilitate ionization. It stands off from the main chamber but is grounded. A series of curved strips or even a titanium box or sphere could be used. Much easier for an amateur to fabricate a titanium liner than to make the entire chamber from the material. Unless of course, a cylindrical container were used since titanium tubing is ubiquitous.

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