Originally Posted by ThePH

Nikasil is a trademarked electrodeposited oleophilic nickel matrix silicon carbide coating for engine components, mainly piston engine cylinder liners. It was introduced by Mahle 1967, initially developed to allow rotary engine pistons to work directly against the aluminum housing. This coating allowed aluminium cylinders and pistons to work directly against each other with low wear and friction. Unlike other methods, including cast iron cylinder liners, Nikasil allowed very large cylinder bores with tight tolerances and thus allowed existing engine designs to be expanded easily, the aluminium cylinders also gave a much better heat conductivity than cast iron liners which is an important factor for a high output engine.