CAL 87 is an immersion process to form a uniform, jet-black coating of cupric oxides that exhibit excellent chemical and heat stability, increase the corrosion protection of the substrate and are highly adherent to the surface. It can be used to blacken a wide range of copper alloys ranging in
copper content from 65 to 100%. The process is useful as a cosmetic “antique” finish or as a base
to increase the adhesion and protection of organic coatings.