HEF Groupe(also known as Hydromecanique et Frottement) is a company that offers surface treatment services and coatings. Its specializes in tribology and functionalization of surfaces, thermochemical treatments and controlled liquid ionic nitriding treatments (CLIN), physical vapor deposition (PVD) and plasma-assisted chemical vapor deposition (PACVD), such as diamond-like carbon (DLC) and the other mechanical and tribological layers, friction rings and components.