Sciencemadness Discussion Board

plating tungsten carbide

BIGRICK - 25-9-2017 at 13:13

does anyone know anyone or company that can plate tungsten carbide? I need to plate 130 bushings with .001" of something like nickel or chrome on the of only.

CRUSTY - 26-9-2017 at 05:50

You can electroplate cobalt-containing WC (most WC does contain cobalt to some degree) with nickel. I'm not sure about chromium though, but I don't see why not. From what I've read, it generally works best after etching the plating surface with sulfuric acid first, or if you want to be fancy, sodium pyrophosphate etching also works apparently. I know that's not what you asked, but it seems like less effort IMO. Most methods I found also mentioned using "high chloride nickel plating". I'm not too savvy on electroplating, but I assume this means you could use nickel (II) chloride as your carrier electrolyte (somebody correct me if I'm wrong).

If you're dead set on finding a company to do this, googling "tungsten carbide nickel plating" yields some decent results. MFTech is one company that may do this (electroless as well), but I'll leave the rest to you.

violet sin - 26-9-2017 at 06:35

Maybe check at:
https://www.finishing.com/index.html

They have discussions on technique as well as people/businesses advertising their services.

vmelkon - 26-9-2017 at 15:39

I'm just throwing this out there.
This is an interesting technique for plating with nickel
https://en.wikipedia.org/wiki/Electroless_nickel_plating

CRUSTY - 26-9-2017 at 17:32

I second the idea of electroless plating, although I'm not sure if it is possible with tungsten carbide. Unfortunately, the standard way to do this (with nickel) is using sodium hypophosphite, which is a List I chemical in the US, and is subject to its own special little set of regulations for some reason (other than the other List I chemicals). Recordkeeping and transaction declaration is apparently mandatory regardless of quantity. Other phosphorus-containing reducing agents will work though.

violet sin - 26-9-2017 at 20:40

There was an interesting little podcast on the website I linked, about nickel/tin plating.
The lost art of nickel tin plating.
https://www.finishing.com/podcast/tinnickelp1.html

It was said to be excellent at corrosion resistance, likened to poor-man's platinum for copper and copper based alloys. High strain coating so not for flexible parts. Polishes to mirror finish. He later mentioned it would work over a copper strike for steel parts. Rather than an alloy it was inter-metallic in nature. Required 155℉ , NaF/Cl, ammonium bifluoride, so not for everyone.

Perhaps it's not practical, but I enjoy reading/hearing about interesting electrochem.. they were able to barrel plate short metal tubes interiors for ink cartridges, to house aggressive pigments. That's pretty cool.

Melgar - 26-9-2017 at 21:07

I'd be shocked if electroless plating worked on metal carbides. The two metals would be in the same oxidation state or at least none of them would be in the 0 state, so I don't see how the reaction would happen. It'd be like electroplating graphite then: possible, but tricky.

Most electroplating is done using multiple layers to get a good combination of adherence and finish. The more different metals that are needed, the more annoying it is. For aluminum, (the most annoying) you need to plate first with zinc, then copper, then nickel before plating with a more decorative metal. Nickel is the easiest and least annoying to plate, because it doesn't really form an oxide layer. When practicing electroplating, quarters, dimes, and nickels were the easiest thing to plate by a long short, because of their nickel finish. So if you have a choice, nickel is a good one, since you can very easily plate it with just about anything else. Not so for chrome.

CRUSTY - 27-9-2017 at 08:38

Quote: Originally posted by Melgar  
I'd be shocked if electroless plating worked on metal carbides. The two metals would be in the same oxidation state or at least none of them would be in the 0 state, so I don't see how the reaction would happen. It'd be like electroplating graphite then: possible, but tricky.


Ooh, plating graphite sounds just lovely. This article is about doing just that, but using the standard electroless plating method. I might just have to try this, sounds like it could potentially produce some nicely supported catalysts.

I wonder if the cobalt in cobalt-containing tungsten carbide alloys would help with plating. It might make for a poor coating, but if the cobalt is in metallic form, "high-hardness" WC (cobalt content is generally increased to improve hardness) could potentially be somewhat more permissive to plating. I dunno. Correct me if I'm wrong.

violet sin - 27-9-2017 at 17:59

https://www.finishing.com/0400-0599/425.shtml

"we found that a high chloride nickel strike (woods) after anodic sulphuric etching gave satisfactory adhesion, although we were plating with 0.0003"- 0.0005" ENP rather than electrolytic nickel."

"Tungsten and other refractory metals can be plated, but only with substantial difficulty. Volume 5: Surface Engineering of ASM's Metals Handbook offers the methods."

"you actually asked about tungsten carbide. Transactions, vol. 66, page 144 (1988) has an article on "Nickel Electroplating onto Tungsten Carbide Powder", and the Shop Problems column in the July 1980 issue of Metal Finishing magazine describes an expired patent on anodic treatment at 1-5 ASI, 68-140 °F, 100-250 g/L sodium pyrophosphate to etch the surface before rinsing and nickel plating."

Just some of the fun on the website I linked. Their suggested library for any electroplating shop is both awesome and terrible... Outstanding knowledge but the cheapest used version of any listed I could buy was 85$ ;( most were a couple hundred.