纳米WC增强Ni基合金喷熔层在不同介质中抗泥浆冲蚀性能研究

采用氧乙炔火焰喷熔工艺制备了Ni60CuMo和纳米WC增强Ni60CuMo两种Ni基合金喷熔层,采用XRD、SEM方法分析了喷熔层的组织结构,测量了喷熔层的硬度和电化学性能;研究了两种喷熔层在淡水和3.5wt.%NaCl介质中的抗泥浆冲蚀磨损性能。结果表明,纳米WC增强Ni60CuMo合金喷熔层的组织结构为纳米WC呈块状均匀镶嵌在γ相固溶体和Cr23C6、Cr7C3等硬质相之间,形成弥散强化,使其硬度提高了约13%;纳米WC增强的Ni基合金喷熔层在3.5wt.%NaCl介质中比Ni60CuMo喷熔层具有更低的腐蚀电位与更高的腐蚀电流密度,它在淡水和3.5wt.%NaCl介质中的抗泥浆冲蚀磨损性能分别比Ni60CuMo喷熔层提高了约53%和20%。纳米WC的加入显著提高了Ni基合金喷熔层的抗泥浆冲蚀性能,但在3.5wt.%NaCl介质中,由于WC与NiCr合金之间形成了大量微电池,加速了喷熔层的腐蚀磨损,使其抗泥浆冲蚀性能的增强效果受到削弱。

Research on Slurry Erosion Resistance of Ni-based Alloy Sprayed and Fused Coatings Reinforced with Nano-WC in Different Media

The Ni-based alloy sprayed and fused coatings of Ni60CuMo and Ni60CuMo reinforced with nano-WC were prepared by oxy-acetylene flame spraying and fusing.The microstructures of the coatings were analyzed by using XRD and SEM.The hardness and electrochemical properties of the coatings were measured.The slurry erosion resistance properties and mechanisms of the two coatings in fresh water and 3.5wt.%NaCl medium were studied.The results show that in the microstructure of the Ni-based alloy sprayed and fused coating reinforced with nano-WC,nano-WC is evenly embedded inγsolid solution and Cr23C6,Cr7C3 etc.,the hard phase,forming dispersion strengthening,which increases the hardness by 13%.Compared with the Ni60CuMo coating,the Ni-based alloy coating of Ni60CuMo reinforced with nano-WC possesses a lower potential and a higher corrosion current density in 3.5wt.%NaCl medium and its resistance of slurry erosion in fresh water and 3.5wt.%NaCl medium,has been enhanced about 53%and 20%higher than that of Ni60CuMo coating,respectively.The addition of nano-WC significantly improves the slurry erosion resistance of the Ni-based alloy coating,but in 3.5wt.%NaCl medium,a large number of micro-batteries are formed between WC and NiCr alloy,which accelerates the erosion-corrosive wear,and its enhanced effect on the slurry erosion resistance of the Ni-based alloy sprayed and fused coating is weakened.