Cathodically protective zinc nickel surface treatment with friction requirement
This standard covers zinc-nickel coatings free from hexavalent chromium for corrosion protection of threaded iron and steel parts with friction requirements. This standard covers both electrolytic and non-electrolytic surface treatments. For non-threaded parts and parts without friction requirements, see STD 121-0004. (For tubes and tube connections, see STD 121-0006).