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How-to for abrasion and corrosion resistant aluminum machine part?

2006

Sirs:

We manufacture an industrial water valve. One of the major components has been made of 303 stainless and we are considering replacing it with 6061T6 aluminum with a suitable coating. Control of the finished part thickness is important, thus the accuracy of coating buildup is a consideration. The part functions as an infrequently sliding element in our valve design. Its mating surfaces would be 304 SS and some EPDM O-rings. desirable coating properties are abrasion resistance, corrosion resistance, and lubricity. I had experience many years ago with a ceramic-teflon coating and wonder if that is a good direction.

I will appreciate any suggestions you might offer.

Regards,

Philip M. Burger, P.E.
engineering - Grandview, Missouri, USA

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2006

If Thickness buildup and corrosion resistance is your main interest. I would suggest High phosphorous Electroless Nickel. My only hold back for this application would be the "contact point with the Stainless... (possible galvanic reaction with the base metal Aluminum) causing the Ni plate to blister and ultimately fail. causing your valve to fail..

If plausible.. consider making the valve out of HDPE or CPVC if high temp application is needed..

Ryan Cook
Toccoa, Georgia

I'd go along with Ryan Cook - Hi P electroless nickel would be a good choice; however I'd like to make an additional suggestion - if lubricity is important, consider an EN coating with codeposited PTFE. Also, heat treatment may help to improve its abrasion resistance.

John Reid
- Brisbane, Qld, Australia
2006