[Milsurplus] Question for Metallurgically-Smart People

[Gordon Smith]

At 08:11 AM 5/21/2020, David Stinson wrote:
>Does anyone here know a way to deposit a metal coating on
>the surface of a quartz crystal blank, without spending a gazillion
>bucks on a Phazer-Atom-Smasher-Hellbore vacuum chamber furnace?

Hi David,
I am no expert (or even novice) in this field, but I did (many years 
ago) do nickle deposition on Silicon. It was part of the old Bell 
Labs science fair kits that they used to send out to high schools. I 
made my own silicon solar cell (very low efficiency) from one of 
their kits. To tap off the electrical charge created by the solar 
cell to copper wires, one had to deposit a nickle mask on the top and 
back of the solar cell. This was done with an "electro less" process 
(I.E. deposition of nickel without using electricity). To make the 
electro less nickel adhere to the silicon, one had to etch the 
surface of the silicon. This was done with a very, very mild Floridic 
acid solution. I suspect that you would have to do the same thing to 
get a good metal coating to adhere to a quartz blank.

However, I think there is a simpler way to do what you want. 
According to this Army R&D Paper : 
https://apps.dtic.mil/dtic/tr/fulltext/u2/734329.pdf (which talks 
about Nickel Electro Bonded Quartz Blanks), most quartz blanks (at 
the time this was written in 1971) have metal plates cemented to 
their sides using a conductive cement, not metal deposited. The main 
reason that metal deposited crystal blanks are the norm now is that 
the metal cemented ones have issues at high G loading and shock 
events (I.E. a close miss from someone shooting at you). So you might 
want to think about just conductive cementing some very thin plates 
onto your quartz crystal blanks.

Hope this helps,

73, Gordon KJ6IKT