Specialty Chemistry Forums > Citizen Chemist

Silver Powder for Making PMC Metal Clay

(1/6) > >>

SteveE:
Hello,

I don't know if any of you have heard of PMC Metal Clay. It's silver powder combined with a binder of some type. It's used in making jewelry. You shape in into any form, fire it in a kiln. The binder burns off and the silver powder fuses together to make a solid piece of jewelry.

My question is.... How do you make silver powder? Surely you wouldn't grind metallic silver into a powder. My guess is they dissolve silver metallic silver into a solution of nitric acid, then precipitate it out with something. What would you use to precipitate it out?

It maybe someone has another way of making silver powder. I'm not trying to make it. I just want to know how it's done.

Corribus:
Ultrafine metal colloids are made by reduction of a cationic metal source (Ag+ in this case). This is how nanoparticle dispersions are made as well. These particles would usually be stabilized by some sort of surface ligand.

A quick literature source shows that fine (dry) silver powder can also be made by a mechanochemical process in which metallic silver and sodium chloride are ball milled, which causes a solid state reaction that forms silver powder and sodium chloride. This is still fundamentally a chemical process, though - Ag+ is reduced to Ag0.

http://onlinelibrary.wiley.com/doi/10.1002/aoc.159/abstract

I'm not sure how chemical suppliers make silver powder in large scales. I would guess it involves some kind of chemical reduction. I do not believe metallic silver can be mechanically ground at low temperature, since apparently FCC metals like silver do not have a brittle-to-ductile transition.

http://physics.stackexchange.com/questions/74983/why-dont-fcc-metals-have-a-brittle-to-ductile-temperature-transition

Arkcon:

--- Quote from: SteveE on March 15, 2017, 05:35:55 PM --- Surely you wouldn't grind metallic silver into a powder.
--- End quote ---

Like Corribus: explained, they do.  They just use a ball mill and a removable grinding powder.  A bar of metal could also be ground on an abrasive wheel, or filed and then pulverized.

Corribus:
There was an error in my previous post. In the paper I mentioned, it wasn't metallic silver and sodium chloride that are ball milled, but silver chloride and sodium.

billnotgatez:
I seem to remember there being patents for PMC

Navigation

[0] Message Index

[#] Next page