Nickel plating that could pass one (1) cycle CASS Test?
Our previous practice of corrosion resistance test for our purchased Nickel plated screw was 24 Hr SST, which gave us fair result.
Recently, the requirement of this test has been changed (upgraded?) to one cycle CASS Test. Thus, we experience corrosion quality problem for these.
I'd like to hear yours experience and ideas that could overcome this. (post-treatment, passivation?)
p/s: Cr plating after Ni is unlikely, appearance of the Ni finishing is required.
There is but nothing in passivation or lacquering that will work on screws. The only way to meet the spec is to go for duplex nickel, with an 80% thickness of sulphur free layer and 20% bright layer.
Bangalore, Karnataka, India
I'm testing on triplex nickel plating. Additional a thin high-sulphur nickel between the semi and bright nickel. Have yet to know the outcome.