Mostly out of curiosity I want to make my own boron-lined neutron tube. I have a fully functional fusor at ~100,000 n/s, hence testing it is not the issue. I also have a working setup to reliably fill it with argon and butane at almost any pressure and ratio, which should make a reasonable fill. Instead I struggle to find any good sources how to cheaply and simply coat a tube with boron, hence my request:
I want to coat the inside of a metal (brass, aluminium, copper, steel, etc.) tube with boron or some compound rich in it. I am unsure how electrically conductive it has to be for the tube to still work, but more conductive should be better. Supposedly pure boron at ~10^5 Ω·m is good enough, but please chime in if you know any details. As I don't want to work with a complex sputtering setup, the two options to get a coating that I could think off are:
(a) Dissolve compound in appropriate solvent, rinse and let it dry.
(b) Mix fine non-soluble powder with volatile liquid (e.g. acetone), rinse inside and let it quickly evaporate. Sufficiently small particles should stick by electrostatic forces.
Obviously (a) is better regarding strength and thickness, but requires a soluble compound that is still somewhat conductive. This should exclude most if not all salts and plastics. Option (b) requires to acquire sufficiently fine powder, likely <1µm. For the latter I am considering buying some amorphous boron and use a metal mortar to get it fine enough.
I want to do this as a cheap side project (lets say below $100). If anyone has some suggestions or knowledge on what should work best then I would be very thankful. I am willing to experiment, so even untested suggestions are very welcome!
Best regards,
Daniel
DIY Boron-lining
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Daniel Harrer
- Posts: 53
- Joined: Fri Aug 18, 2023 11:01 am
- Real name: Daniel Harrer
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Rich Gorski
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- Joined: Mon Aug 01, 2022 4:34 pm
- Real name: Rich Gorski
- Location: Illinois
Re: DIY Boron-lining
Daniel,
Coating the inside of a metal tube with a boron compound might be done in the same way phosphors are coated on the screen of a CRT. In the case of the CRT the phosphor powder was mixed with DI water plus a little binding agent such as sodium silicate and then poured into the CRT bottle. The CRT bottle was then rotated slowly to evenly spread and deposit the phosphor around the faceplate. Then baked at like 200C to dry. The sodium silicate acts as an adhesive to bind the phosphor particles to each other and to the glass.
For a tube you could try a similar technique. I suggest a bath of your boron + DI water + sodium silicate slurry and submerge the tube about 1/2 way in. Then slowly rotate the tube (1 hour ??) until the slurry is mostly dry and with an evenly deposited coating. Then bake it out for 1 hour.
I have no idea on the ratio of sodium silicate to water to use. Experiment...
Rich G.
Ps. you might google how the phosphor is applied to a fluorescent tube. I'm sure its a similar process.
Coating the inside of a metal tube with a boron compound might be done in the same way phosphors are coated on the screen of a CRT. In the case of the CRT the phosphor powder was mixed with DI water plus a little binding agent such as sodium silicate and then poured into the CRT bottle. The CRT bottle was then rotated slowly to evenly spread and deposit the phosphor around the faceplate. Then baked at like 200C to dry. The sodium silicate acts as an adhesive to bind the phosphor particles to each other and to the glass.
For a tube you could try a similar technique. I suggest a bath of your boron + DI water + sodium silicate slurry and submerge the tube about 1/2 way in. Then slowly rotate the tube (1 hour ??) until the slurry is mostly dry and with an evenly deposited coating. Then bake it out for 1 hour.
I have no idea on the ratio of sodium silicate to water to use. Experiment...
Rich G.
Ps. you might google how the phosphor is applied to a fluorescent tube. I'm sure its a similar process.