FORD – WSS-M21P51
Fastener Finish, Electroplated Zinc-Nickel, Trivalent Chromium Passivate
The materials defined by these specifications are corrosion protective coatings over steel and iron substrates. All consist of an alkaline zinc nickel alloy and trivalent chromium passivate. A2, A3, A4, A5 and A6 are also coated with a clear sealer to increase corrosion resistance and/or to provide consistent torque-tension control.