Nikasil (an abbreviation of nickel silicon-carbide) is an electroplated composite coating comprising of a nickel matrix holding silicon carbide particles in place (similar to rocks and cement in concrete). The surface nickel is honed or machined away, exposing the silicon carbine which provides a very hard surface for the piston rings to run on.
Nikasil is applied in a single electroplating bath process and any materials that can be plated with other metals can be plated with Nikasil. Composite coatings have the unique advantage of combining two or more properties of separate materials to produce new materials with superior properties. The Electrosil composite coating has a wear resistance 4 to 10 times that of a cast iron sleeve or chromium bore.
Wear resistance is one of the most outstanding properties of the Electrosil coating but it also provides excellent frictional characteristics, in part due to its superior wet-ability. It is very easy to maintain hydrodynamic lubrication conditions because of the oleophilic structure of the coating. Additionally, the coating has excellent corrosion resistance and a high upper operating temperature which is required to protect aluminium bores used in internal combustion engines.