solution for schwarzfaerbung at room temperature and method for formation of a black coating on a ferrous metallsubstrat.

摘要

A room temperature black coating for ferrous metal is formed in a solution based on selenium dioxide, an inorganic copper salt and an organic acid. The solution virtually eliminates the formation of a selenium iron precipitate which results from conventional blackening agents in which an inorganic acid such as phosphoric, sulfuric, nitric or hydrochloric acid is used. Further, the virtual elimination of the precipitate produces the additional benefit that the user needs handle and ultimately dispose of only an insignificant amount of toxic selenium iron or selenium phosphate compound materials.