Metal finishing Q&As since 1989

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Chrome Plate of the Brass Ball in a Ball Valve

We purchase chrome plated brass balls for use ball valves used in different types of water service. Typically, the water comes from potable sources and it may be dirty with particulates. The chrome protects the brass from moving particles and provides a good sealing surface for teflon seats. Currently the balls are nickel plated with a flash of chrome. Our specification for the plating requirement is not well defined. We have seen certain instances where the chrome on the seems to de-plate during surface. We believe this may be due to chemicals in the water. I am looking for some advice on the plating specification. Can the chrome be plated directly to the brass (hard chrome) and would this help us? Or, should we require thicker chrome be plated over the nickel - how thick can this plating typically be?

Jim Hoskins
product designer - Glocester, Rhode Island, USA
April 10, 2009

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April 27, 2009

I think that plate peeling is a plating problem and not a water caused problem. Pitting would be a typical water caused problem. Typically, this is caused by the nickel passivating because it either was not reactivated properly OR did not move thru the rinse tanks to the chrome tank with all due haste.
Nickel chrome will be far better than just chrome. Dual nickel-chrome would be slightly better, but that will not help the peeling problem.
Electroless nickel only, might be a better solution but may cost more. It might also have problems in use that I am not aware of.

James Watts
- Navarre, Florida