Quartz (glass) plating (coating)

[nourgostar]

I am trying to coat a section of a 6" x 17" x 1.5mm fused quartz plate with a thin conductive layer(copper,chrome,nickel or etc). I was looking at caswell electroless nickel plating kit and was wondering if this could be used to coat nickel on a quartz or glass plate. If not, which kit would do this?
would it be transparent then?

[engineerscott]

Re: Quartz (glass) plating (coating)

I think the process normally used to put a metallic coating on any sort of glass would be Chemical Vapor Deposition (CVD). This involves placing the item in a vacuum chamber then heating a quantity of the desired metal until it vaporizes then condenses on the item you are coating.

The only process that Caswell sells that might possibly work is electroless nickel and I am pretty doubtful that it will. Maybe if you used a supersaturated solution you might get some to condense out onto your quartz.

Google on Chemical Vapor Deposition and you should find a process that will work.

[engineerscott]

Re: Quartz (glass) plating (coating)

I was thinking a bit more about your question and I was wondering if you could talk more about your application. Are the optical properties of the finished product very important to you? If not you might be able to etch one side of your quartz in HF (hydroflouric acid) to prep the surface a bit to get the metalization to stick better. This would definitly change the optical transmission characteristics. It would change the surface into a matte finish and would make it somewhat cloudy. HF is really nasty stuff btw and should only be handled by someone who knows the dangers.

Back in your original question you asked if a metalized surface would be transparent. This depends on the film thickness. A thin film will give you a semi-transparent effect. If you recall the face visors that astronauts use when they go EVA then you get the idea. In fact, the sun visors are produced by depositing a thin gold film on glass and are designed to block specific portions of the spectrum and to darken everything in general so that the sun's brightness does not damage the astronaut's vision. The thicker the film the more it will block visible (and invisible) wavelenghts. If the metal coating is thick enough it will be completely opaque.

[eprigge]

Re: Quartz (glass) plating (coating)

I don't think the electroless nickel will work for you. Electroless plating of insulators usually involves a catalyst pretreatment that puts a transparent layer of metal ions on the surface to stimulate the electroless process.

You could always use a mix used to silver glass mirrors. It's a kind of electroless method, doesn't need any catalysts.

[mcaswell]

Re: Quartz (glass) plating (coating)

Aha! Thats sounds like a plan. Actually, I think we have a supply of Silvachrome silvering solution still left. We used this material to reproduce a chrome like finish, but found it was too complex on a small one-off operation, and needed too much support.


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