Abstract: Process for the preparation of ceramic materials for parts having friction surfaces subject to friction and free from auto/self-adhesion under stress or during aging. A precursor of the ceramic undergoes successive operations of pressing, sintering, polishing the surface obtained, cleaning the solid gangue resulting from the polishing, roasting in the presence of oxygen, and a doping treatment for increasing the dielectric susceptibility and homogeneity of the ceramic material adjacent the friction surfaces and to increase the mobility of the charges.

Abstract: Process for the preparation of ceramic materials for parts having friction surfaces subject to friction and free from auto/self-adhesion under stress or during aging. A precursor of the ceramic undergoes successive operations of pressing, sintering, polishing the surface obtained, cleaning the solid gangue resulting from the polishing, roasting in the presence of oxygen, and a treatment aimed at increasing the dielectric susceptibility and homogeneity of the ceramic material adjacent the friction surfaces and to increase the mobility of charges.

Abstract: A steel part, and more particularly a stainless steel part, is coated with a varnish containing particles of an additional metal such as tin or aluminium, and it is heated at a temperature situated above the melting point of the said additional metal, but outside a zone comprised between 700.degree. C and 970.degree. C. The treated part may be annealed at about 500.degree. C. The varnish may besides contain particles of a substance having a melting point situated above the melting point of the additional metal, but which may dissolve in the liquid phase of the latter. This substance may be chromium, molybdenum, cobalt, titanium, vanadium, nickel or copper.