Below is a list of Sulfuric Acid Anodizing manufacturers from Spokane, Washington. Sulfuric acid anodizing is an electrochemical process in which the outer layer of a substrate is hardened through oxidation to become more corrosion and wear-resistant. Although chromic acid anodizing has been around longer and is more commonly used in this capacity, sulfuric acid anodizing is becoming increasingly popular due to the known ill-effects of chromic acid, the use of which is restricted by the Environmental Protection Agency (EPA).