Progress in Preparation of Hard Phase Reinforced Ni-based Alloy Composite Coating by Laser Cladding

For the sake of satisfying diverse service conditions, many engineering components should be equipped with excellent surface properties, such as high hardness, good wear resistance and corrosion resistance. Ordinary metal material can achieve improved surface properties by cladding the alloy powders on its surface. The laser cladded coating holds favorable adhesion property, excellent microstructure, small heat affec-ted zone and outstanding mechanical properties. The commonly used laser cladding approaches primarily include preset powder method and synchronous powder feeding. The common cladding materials are mainly divided into three categories, namely Fe, Co and Ni based. The Fe-based coatings feature high hardness and wear resistance, and lower price as well. Nevertheless, the Fe-based coating is prone to produce defects during the preparation process, resulting in the decline in performance and reliability of the coating. Co-based coatings hold excellent high temperature resistance and corrosion resistance, yet their mechanical properties are poor and the price is extremely high, which seriously blocks their widespread application in industry. Ni-based coatings possess excellent wear resistance, good toughness and wettability, and their production cost is relatively economical, which show broad application prospects. In recent years, great efforts have been put into the research of Ni-based coating. At present, the commonly used approach for strengthening Ni based coatings include adjusting the process parameters of laser cladding and adding hard phases or appropriate elements to the Ni based coatings. Many researchers have concentrated on optimizing the composition of Ni-based alloy powders, that is, adding hard phases or appropriate elements to Ni based powders to enhance the properties of the Ni coating. The major hard phase particles added to Ni based coatings include WC, NbC, TiC, TaC and VC. Attempts that adding certain compound elements to assist the generation of reinforcing phases in laser cladding process by in-situ reaction have been made by researchers. For instance, the addition of pure Nb powder (or Nb2O5) and graphite powder contribute to generate NbC, the addition of pure Ti powder and graphite powder is conducive for the formation of TiC by in-situ reaction. Some researchers have tried to introduce a single element including Nb, Ti, Al, Ta and so on, in order to improve the performance of the coating. Besides, the effect of rare earth elements on the properties of coatings have been explored as well. Ni-based alloy coating prepared by laser cladding are endowed with high bonding strength, excellent corrosion resistance and wear resistance, exhibiting a broad application prospect in engineering. The mechanical properties of the coatings can be further enhanced by improving the composition of the alloy powders. In this article, the research progress of hard particle reinforced Ni-based alloy composite coatings is reviewed. The problems that need to be solved for the hard particle-reinforced nickel-based alloy coatings are pointed out, and the prospects of the research are also discussed. © 2019, Materials Review Magazine. All right reserved.