Variable Hardness Nanocomposite Coating

A variable hardness nanocomposite coating and method for its production. The variable hardness nanocomposite coating can be applied as a single layer on metallic engine components that require a break-in to achieve physical mating of interacting surfaces thereby reducing friction and optimizing engine performance. The single layer nanocomposite coating has a relatively higher carbon content and lower hardness at the surface region and a relatively lower carbon content and relatively higher hardness region as one proceeds towards a surface of the metal component being coated.