Black Chromate with Zinc
Black chromate is a chemical conversion coating that is applied over zinc plating during the surface coating process. Zinc plating is a soft, ductile, marginally solderable, corrosion-resistant finish. It protects the substrate and corrodes before the base metal, unlike most other commonly plated metals. Black chromate films are typically very thin, around .000001” and contribute no measurable thickness to the overall coating.