Plasma nitriding is a surface treatment process that enhances the hardness and wear resistance of metals. It involves placing the metal part in a vacuum chamber filled with nitrogen gas. An electric field is then applied, creating a plasma that ionizes the gas, allowing nitrogen ions to diffuse into the surface of the metal. This process results in the formation of a hard, wear-resistant layer, improving the performance and longevity of components used in various applications, such as automotive and aerospace industries. Plasma nitriding is favored for its ability to treat complex shapes without altering the dimensions of the parts.