Blackening Chemicals For Metalworking Blackening Chemicals For Metalworking - Blackening chemicals for metalworking are used to create a protective, darkened surface finish on metals. The type of blackening process depends on the metal you’re working with and whether you need a hot, mid-temperature, or cold blackening method. 1. Cold Blackening (For Room-Temperature Applications) - Uses selenium-based or copper-selenide solutions. - Fast and easy, but provides lower corrosion resistance than hot black oxide. - Common for touch-ups or small parts. 2. Blackening for Aluminum (Anodizing or Chemical Methods) - Anodizing with Dye – Creates a durable black finish. - Black Oxide for Aluminum – Uses a molybdate-based process for a matte black look. # Blackening Chemicals Manufacturer.