BLACKENING PRODUCTS FOR METAL SURFACE - Blackening products for metal surfaces are used to create a black oxide coating, providing both aesthetic appeal and corrosion resistance. Here are some common types of blackening products and methods: 1. Cold Blackening - Cold Black Oxide Solutions: These are water-based solutions that can be applied at room temperature. They are ideal for small-scale or less industrial applications. 2. Hot Blackening - Hot Black Oxide: This involves immersing the metal in a series of heated tanks containing caustic soda, nitrates, and nitrites. The process is more suitable for large-scale industrial applications. 3. Room Temperature Blackening - Room Temperature Blackening Solutions: These are similar to cold blackening but specifically formulated to work without heating