Sherardising is a zinc diffusion process for the formation of zinc-iron layers on ferrous work-pieces. It is generally used for corrosion protection, but is also used as an adhesion promoter. The pre-treated components are placed in a rotating drum with zinc powder and an inert filler, such as quartz sand or corundum. By heating, zinc evaporates and diffuses into the metal component to form a firmly adhering zinc-iron alloy with the iron-containing surface.