Ask the Expert Question-and-Answer Archive
(Hard Chrome Plating)

by Randy Taylor, Advanced Tooling Corporation.
June, 2013

Maximum Thickness of Chrome Plating on Hydraulic Shaft

Q. Sir, What should be the maximum thickness of chrome plating on hydraulic shaft to get maximum life without chipping off?

A. Hard chrome usually behaves well in the 0.0005 to 0.010 thick range. Most aircraft hydraulic requirements are in the 0.003 to 0.005 thick range after chrome grinding. You don't need a lot of chrome to do the good work of sealing and wear resistance. Theoretically you can put on much more thickness upwards of 0.025 - 0.030 for certain salvage requirements. But those events should be carefully evaluated and used only on a limited basis.

Chipping is a sign of poor adhesion. If you are referring to chipping the edges, the problem can usually be resolved by better masking and anode design techniques. If you are referring to "chipping" of the chrome coating on the working surface of a hydraulic shaft, then we are more likely getting into issues with process control.

Specifically 1. "preparation" of the base metal 2. Current Density 3. Bath chemistry and temperature.

As usual in hard chrome plating, there is probably no simple answer.

I hope this brief response is helpful. Advise.

Randy Taylor





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