Microstructure and Wear Resistance Evolution of HVOF-Sprayed WC-(W,Cr)2C-Ni Coating with Post Heat Treatment In Air Atmosphere
WC-(W,Cr)2C-Ni coating was prepared on lCrl8Ni9Ti stainless steel and C-276 Ni-base Hastelloy by high velocity oxy-fuel (HVOF) spraying. The effect of post heat treatment in air atmosphere on the microstructure, phase composition, micro-hardness, fracture toughness, and wear resistance of HVOFsprayed WC-(W,Cr)2C-Ni coating was investigated. The microstructure and phase composition of the coatings were analyzed by means of field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The microhardness and fracture toughness of the coatings were measured using a microhardness tester and a Vickers hardness tester. Moreover, dry friction and wear behavior of the coatings sliding against Si3N4 ball was investigated using an oscillating friction and wear tester; and the worn surfaces of the coatings were analyzed by means of scanning electron microscopy (SEM). It was found that heat treatment within 500-800 °C resulted in crystallization of amorphous phase in as-sprayed coating, generating nanoscale new phases such as N1WO4, CrWO4 and Cr2WO6. Besides, heat treatment led to increase of the microhardness of as-sprayed coating, and the highest microhardness was obtained after heat treatment at 800 °C. The fracture toughness and wear resistance of the as-sprayed coating increased with increasing heat treatment temperature up to 700 °C but tended to decrease with further elevating temperature. In other words, the mechanical properties and wear resistance of the as-sprayed coatings were worsened owing to excessive growth of oxidation grains and depletion of ductile Ni binder after heat treatment above 700 °C. Thus it was suggested that as-sprayed ceramic composite coating should be post heat treated in air at a moderate temperature of 700 °C so as to achieve the optimized mechanical properties and wear resistance.
HVOF WC-(W,Cr)2C-Ni coating post heat treatment microstructure wear resistance
Hou Guoliang Zhou Huidi An Yulong Liu Guang Chen Jianmin Chen Jie
State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of
国际会议
西安
英文
388-393
2011-05-11（万方平台首次上网日期，不代表论文的发表时间）