How is decorative chromium electroplating different from hard chromium plating?

Decorative and hard chromium plating are both forms of electroplating that utilize solutions of chromic acid, but they serve distinct purposes and differ in their application.1

• Decorative Chromium Plating: This process is primarily used for aesthetic purposes, such as on automobiles and household appliances. It typically involves a very thin deposit, ranging from 0.000254 to 0.000508 millimetres (0.00001 to 0.00002 inches) in thickness, and is usually applied over a layer of nickel. It is valued for its ability to retain a bright, polished appearance indefinitely.21

• Hard Chromium Plating: This process is utilized for its functional mechanical properties rather than its appearance. It is specifically employed to improve the wear resistance of machine parts, provide a low coefficient of friction, and offer heat resistance. Additionally, hard chromium plating is used to build up worn or undersized parts to restore them to their proper dimensions.12