Chromium, as the most widely used material for coatings, can provide wear-resistant and corrosion-resistant coatings for cutting tools, molds, components, decoration, bathroom and other fields. Hard coating chromium (Cr), Chromium nitride (CrN) and DLC coating can provide the best protection for engine components such as automobile piston rings and valve tappets, and extend the service life of important parts. Decorative coating chromium can provide a smooth and wear-resistant surface for bathroom, watch, glasses, 3C electronic products, and various other products.