hard chrome on aluminum?

[BobM3]

Can Hard Chrome be applied to aluminum? We're looking to get a hard surface resistant to abrasion.

[Geof]

I have never heard of hard chrome on aluminum, however, have you considered hard coat anodizing with a bonded teflon coating. This is hard and abrasion resistant.

[BobM3]

I've heard of that. Have you any experience with hard coated aluminum? The application is a drum with galvanized aircraft cable wrapped around it. The cable tends to really dig into the surface.

[Geof]

Yes but only with flat surfaces in contact.

I think for your situation it is likely that nothing will work because the underlying material is too soft. No matter how hard the coat is it is very thin so a very small contact area such as you get with a cable is going to deform the underlying metal and fracture the coating.

An analogy is walking on deep snow with a crust of ice; you are fine with snow shoes to spread the load but ice skates would leave you floundering.

How about machining a 'thread' in the drum for the first wrap of cable to lie in? This means the cable is making contact over a larger surface area.

[MrWild]

If there is a soft metal underlaying the hard chrome, it will flake off during use. This is a very bad idea. Change the AL for a steel.

[NC Cams]

Hard chrome is somewhat of an oxymoron. Industrial chrome is rated at a Hrc of around 70. This is definitely HARD.

Aluminum on the other hand is soft and quite compliant - not anywhere close to Hrc 70. The problem is that the applicatio of a subtantial amount of chrome over that of a "flash chrome plate" runs the risk of being "eggshell hard".

THus, a substantial plating of chrome will be hard but the aluminum soft and more compliant. Unless the chrome is VERY well bonded, it WILL flake off because the aluminum can/will deform readily and the chrome won't - it will crack and then peel.

Can aluminum be chrome plate???. YES, definitely. A noted aftermarket piston supplier formerly in located in Cleveland Ohio (now out of the business of MFG of forged pistons, only the "name" remains in the market) made forged aftermarket replacment pistons for the Vega for YEARS.

Whereas the OEM Vega pistons were iron plated aluminum to run in the silicon lapped aluminum bores, the after market pieces were DEFINITELY chrome plated.

They worked well and the chrome seemed to adhere well until/unless the clearance was set wrong and you siezed a piston in the bore....