FIELD: processes.
SUBSTANCE: invention relates to a method of forming on surface of a metal part a protective coating containing aluminium and zirconium. In this process said part and a cement made of an aluminium alloy are brought into contact with a gas at a treatment temperature in a treatment vessel, gas comprising a carrier gas and an activator, activator reacting with cement to form a gaseous aluminium halide, that decomposes on surface of part, depositing metallic aluminium thereon. Activator containing a zirconium salt obtained from granules of a zirconium salts wherein disassociation reactions of said zirconium salt taking place within a disassociation temperature range with formation of a Zr metal coating on surface of part. Assembly comprising part, cement and zirconium salt granules is progressively heated in chamber from room temperature up to treatment temperature. Process being characterised in that treatment chamber is maintained at an overpressure with no carrier gas flow throughout temperature range corresponding to disassociation reactions of zirconium salt. Circulate carrier gas through chamber after chamber temperature exceeding temperature range of disassociation of zirconium salt, form diffuse aluminised layer on surface, form an additional aluminising layer on diffuse aluminising layer formed on surface of metal part. Zirconium is deposited at interface between diffuse aluminising layer and additional aluminising layer.
EFFECT: product life is increased by improving its corrosion resistance.
10 cl, 2 dwg
