Preparation And Properties Of Ni-Cr-W Based Alloy Powder Composite Coating By Argon Arc Cladding

Ni based alloy powder coating was prepared by using argon arc cladding technology on40Cr substrate surface.Firstly,the influence of cladding current,cladding speed and argon flow rate on the cladding coating was studied to determine the optimum cladding parameters.In order to further enhance the coating properties,the WC/Cr₇C₃ enhanced phase was formed in situ by adding C into the nickel base alloy coating.At last,the B₄C is added to the optimum C content,so as to achieve the effect of compound enhancement.The microstructure,hardness,wear resistance and corrosion resistance of the coatings prepared under different conditions were studied.The experimental results show that when the cladding current is too large or the cladding speed is too small,the cladding layer can be welded or not formed well.But the cladding current is too small or the cladding speed is too fast,so that the thickness of the cladding layer becomes smaller,the width of the cladding is narrow,and even the complete coating can not be obtained.The microstructure of the cladding coating can be effectively refined by reducing the cladding current and increasing the cladding speed.The surface morphology of the coating is the best when the cladding current is 180A,the cladding speed is 75mm/min and the argon flow rate is6L/min.The phase analysis shows that the coating mainly has Ni based solid solution,in situ formed carbide and other phases,With the increase of C content,the hardness and wear resistance of the coating are increased at first and then decreased.The hardness and wear resistance of the cladding coating are better when the content of C is 5%,the corrosion resistance of the coating is relatively better;The addition of proper amount of B₄C can make the grain refinement and the second phase uniform distribution.When the content of B₄C is 5%,the surface hardness of the coating is higher,the forming property is the best,and the wear resistance and corrosion resistance of the coating are the best,When the B₄C content is more than 5%,the coating quality is decreased,the forming property is poor,the hardness increasing is not obvious,and the corrosion resistance is decreased.