Blackening Chemicals For Metal - Blackening chemicals for metal, also known as black oxide or blackening agents, are used to create a thin layer of black or dark finish on metal surfaces. This process is often used for steel, stainless steel, copper, and brass to improve corrosion resistance, reduce light reflection, and provide an aesthetically pleasing, darkened finish. Here are some commonly used blackening chemicals and processes for metals: 1. Black Oxide for Steel - Cold Black Oxide: Ideal for room temperature applications, it creates a black finish without the need for heat. It’s often used in workshops or for smaller applications where high temperature processes are impractical. - Hot Black Oxide: Performed at high temperatures (285°F or around 140°C), this method produces a deeper, more durable black oxide finish. It’s commonly used in industrial applications. - Chemicals involved include sodium hydroxide (NaOH), sodium nitrite (NaNO2), and other oxidizing agents. # Blackening Chemicals Manufacturing.