Piston materials

[shbazjinkens]

What kind of metal is most resiliant to the type of friction a piston is known to encounter? I've heard of deep chrome plating before, is that the most preferable option? Will I be able to get aluminum electroplated with it?

 

[Tmoose]

I think that regarding sources of frictional losses in an engine the rings are usually considered to be much more significant than the piston.

Even then, the piston "friction" is likely to be related to the viscous oil drag, rather than piston against the cylinder bore directly. Hence, more throttle is needed to keep a cold engine running, and a fast idle is needed when the oil is cold.

In my mind the purpose of a piston coating is to provide insurance against scuffing in emergency situations.
Except when the bore is essentially aluminum, when an iron plated piston is often used.

When trying to Keep chrome plating attached to steel some value of bond strenght is used for calculations. I think it is just a few 1000 psi. I'm thinking it probably would be no higher with aluminum. The stresses resulting from thermal gradient could be a killer, and tought to estimate/calculate.