Black Chrome is a semi hard, non-reflective,
abrasion-resistant, heat and corrosion resistant coating (approximately
.0002” thick). The Black Chrome finish can be rendered very lustruous for
consumer decoarative applications; and clear coated for a functional use.
The Black Chrome process has poor throwing power; and conforming anodes
are necessary for coverage on intricate shapes. This coating is applied
after heat treating and all mechanical operations are performed.
The Black Chrome surface may be waxed
or oiled to darken the surface. Coating provides limited corrosion protection,
but added protection can be obtained by specifying underplate such as nickel
The coating color is a dull dark gray,
approaching black; and becomes (black) pearl-like when polished. It shall
approximate color plate 37038 of Fed. Std. No. 595. Steel parts with Rockwell
hardness in excess of Rc 40 shall be stress relieved prior to plating by
baking one hour or more at 300° F to 500° F and baked after plating
375 F° ± 25 F° for 3 hours minimum for induced hydrogen