Formation And Morphology Analysis Of P92Steel Rare Earth （CeCl₃） Ni-Al Composite Coating

P92steel is mainly used in (ultra) super power uints and served in high temperatureand high pressure condition. The corrosion resistance of P92steel will worsen sharplyfrom630℃to650℃or higher temperature environment. With the development of surfacetechnology, surface coating technology and surface modification are not only used in thetraditional means of material surface protection, but also the simple and feasible way forimproving high temperature oxidation resistance of P92steel antioxidant in hightemperature.This paper mainly introduces the preparation and morphology of P92steel rare earthNi-Al composite coating in order to improve oxidation resistance and corrosion resistanceof P92steel. The nickel layer is prepared by the ordinary electroplating plating so that thethickness is uniform and nickel layer has homogeneous microstructure and strongintegrating force on the surface of P92steel and add rare earth elements in the aluminumagent of infiltration temperature pack cementation aluminizing. The macroscopiccompleteness was observed by naked eye. The binding force of the nickel plating layer wastested by grinding coating with grinding wheel and thermal shock test method. The coatingwas observed in LSCM and SEM in order to test the uniformity and thickness of nickelplating layer. The energy spectrum and phase of Nickel plating layer and compositecoating are analyzed by optical microscope and SEM.The results show that: The best process for nickel plating was mechanical level off,washing, unoil, washing, acid etching, washing, excitation, washing, preplating,electroplate and recycle. The bonding strength, uniformity, and the purity of nickel ofnickel plating layer are best when plating temperature is45℃, electric current density is2~2.5A/dm2, pH of plating solution is4~4.5under the same pretreatment process. Thethickness of coating is about100μm after2hours of electroplating. The coating quality isbetter after adding rare earth in the aluminizing agent. When rare earth content is2%, the average thickness of aluminized layer is maximum, about22μm. When rare earth contentis0%, the average thickness of aluminized layer is minimum, about16μm. Compositecoating of Ni-Al compound is always Ni2Al3whether adding rare earth or not. The additionof rare earth will not affect the structure of the composite coating.