How do I prepare small carbide parts for hard-chrome plating?

Q. Our company wants to hard-chrome plate small carbide parts. How do I prepare the surface and get the chrome to stick to the part? I am using a fluoride bath. V.E.

A. As a chemist, I must point out that there are many different types of carbides out there. Amongst machinists and people who work with cutting of materials, the term carbides is usually used as shorthand for tungsten carbide materials. Tungsten carbide is a very hard material and is used for cutting and machining tools of various types. It is not the easiest material to plate.

There are various reports of successful plating of tungsten carbide parts. One procedure that seems to work on a consistent basis is to treat the parts anodically in a 100-250 g/L of sodium pyrophosphate solution for a few minutes, rinse and than plate in a Wood’s nickel plating bath. I do not have any firsthand information on this procedure.