What is coating?

A coating is a covering that is applied to the surface of an object, usually referred to as the substrate. The purpose of applying coatings may be decorative, functional, or both. Coatings may be applied as liquids, gases, or solids, and can range in thickness from a few nanometers to millimeters. Common uses include protecting materials from corrosion, abrasion, and weathering, as well as providing specific properties like color, gloss, electrical conductivity, or thermal insulation. Examples include paint on cars, anti-reflective coatings on lenses, and protective layers on electronic components.