Coatings for 308 Aluminum
Coatings for 308 Aluminum
(OP)
I am currently using cast 308 aluminum and need a protective coatings similar to an anodized hard coat. What coating options exist for 308 as in nickel plating, chrome plating, etc? It should preferrably have an attractive black finish. Thanks!





RE: Coatings for 308 Aluminum
Electroless nickel plating can give you a very shiny surface to a surface that looks like a grain structure (very nice in my opinion). It is also chip resistant. You can vary the hardness from around RC35? to RC65 by changing the phosphorus content and heat treatement. It can provide good wear resistance and lubricity. However, it will not provide good corrosion resistance in an agressive environment, although thicker coatings are supposed to offer better corrosion resistance. But if a corrosive species like chlorides reach the aluiminum it's all over.
Nickel plated aluiminum is very cool because it is lightweight but doesn't look like aluminum, so unless you know about nickel plating it appears to be unobtainium. If you can live with shiny or grainy and are not in a corrosive environment it is a very good option. But I'm not sure how it would look on a net cast part.
I don't see much advantage to chrome over electroless nickel.
You didn't mention why you can't use a hard anodize or a decorative anodize. If you were considering hard anodize I assume you need wear resistance?
I can't remember whats in 308 aluminum and I don't know if it causes any particular plating or anodizing challenges. Maybe that's why you are looking for something other than anodize?
Beware of platers and anodizers. In my experience getting high, consistant quality is difficult (bordering on impossible). If you are pushing the capabilities of the coating this becomes a big issue.
Do a search on this forum using "nickel plating" or "electroless nickel".
Sorry, I don't know 0f anything black except anodize.
RE: Coatings for 308 Aluminum
Essentially we are looking for wear resistance, and we have had good success with a hard coat anodize on higher grade aluminum (6061 i believe), but we would like to be able to use the lower cost 308.
Thanks for the help.
RE: Coatings for 308 Aluminum
RE: Coatings for 308 Aluminum
There are some exotic ceramic coatings available which are applied by thermal spray techniques. I suspect they are very pricey.
Also, you might run a test to see if Type II anodize would give you enough wear resistance. I believe it's basically the same stuff but not as dense. Type II is usually more flexible as to the substrate.
RE: Coatings for 308 Aluminum