Hard chromium coatings, abrasive wear resistance

Chromium electroplating is also used as decorative and hard coatings. Colored and tarnish-resistant chromium decorative coatings are produced over a base deposit of copper and/or nickel for applications such as those noted above for nickel. Hard chromium coatings are used for hydraulic pistons and cylinders, piston rings, aircraft engine parts, and plastic molds, where resistance to wear, heat abrasion, and/or corrosion are required. 

In addition, the extreme hardness of the metal, its low coefficient of friction and its non-galling property, combined with its corrosion resistance, make it particularly valuable as a coating where resistance to wear and abrasion are important. Thick deposits applied for this purpose are referred to as hard chromium to distinguish them from the thin decorative deposits. 

---