Auto Blackening Chemical VITARAG CHEMICAL IS BLACKENING CHEMICAL MANUFACTURE. - Auto blackening, also known as chemical blackening or black oxide coating, is a process used to impart a black finish to metal surfaces, typically steel and iron. This finish is not only aesthetic but also provides a degree of corrosion resistance. The process involves a series of chemical reactions that form a thin, black oxide layer on the surface of the metal. - Cleaning: . The metal surface is thoroughly cleaned to remove any grease, oil, dirt, or rust. This is crucial for the chemical reaction to proceed uniformly. Common cleaning methods include alkaline cleaning, acid pickling, and solvent cleaning.