FORMATION OF COATING FILM HAVING EXCELLENT RESISTANCE TO CORROSION AND WEAR ON METAL

摘要

PURPOSE:To obtain the subject coating film having sufficient resistance to corrosion and wear even in a corrosive gaseous atmosphere by coating the surface of a metal with a Cr layer, applying a slurry contg. ceramic particles thereon, calcining the slurry to form a porous coating film, and then repeating the impregnation of the film with chromic acid and the heating of the film. CONSTITUTION:The surface of a structural metallic member is coated with Cr having 3-50mum thickness by electroplating, and then a slurry of ceramic particles of silica, etc., having =3mum diameter in a liq. such as chromic acid is applied thereon in 10-200mum thickness, dried, and calcined to form a porous ceramic coating film. The pores of the coating film are impregnated with chromic acid, and the impregnation and heating to =500 deg.C are repeated plural times to convert the chromic acid to chromium oxide and consequently to density the coating film. By this method, the lower Cr layer is firmly attached to the upper ceramic layer through chromium oxide, and a coating film having excellent resistance to corrosion and wear can be obtained.