超声速等离子喷涂Ni60A涂层的滚动接触疲劳寿命

制备高质量的超声速等离子喷涂Ni60A涂层,并研究该涂层的滚动接触疲劳性能及寿命。通过正交试验对Ni60A涂层的4个主要喷涂工艺参数(喷涂电压、喷涂电流、Ar气流量和喷涂距离)进行优化设计,通过分析孔隙率和显微硬度值的大小,综合评价喷涂层质量。利用Image J2x孔隙率计算软件计算涂层孔隙率,利用扫描电镜分析Ni60A粉末和喷涂层的微观结构,采用显微硬度计测定涂层的显微硬度,利用RM-1接触疲劳/磨损多功能试验机对涂层进行不同载荷条件下的接触疲劳试验,并建立Weibull失效概率图。结果表明,通过正交试验可以获得高质量的超声速等离子喷涂Ni60A涂层,超声速等离子喷涂Ni60A涂层的最优喷涂工艺参数为:喷涂电压170 V,喷涂电流370 A,Ar气流量110 L/min,喷涂距离110 mm,通过最优参数制备得到的Ni60A涂层的孔隙率为1.05%,显微硬度为1 086 HV_(0.2);在不同接触应力水平下,Ni60A涂层的寿命服从Weibull分布,通过Weibull失效概率图可以在一定范围内预测某一工作载荷下涂层的接触疲劳寿命。

Rolling Contact Fatigue Life of Supersonic Plasma Sprayed Ni60A Coatings

To improve the quality of Ni60A coatings deposited by supersonic plasma spraying technology, and to investigate the rolling contact fatigue of coatings. Four main parameters (spraying voltage, spraying current, argon gas flow rate and spraying distance) of supersonic, plasma spraying processing are optimized, through evaluation of microhardness and porosity by orthogonal test of four factors three levels. The microstructure of Ni60A powders and coatings is analyzed by means of scanning electron microscope. The microhardness and porosity of coatings are measured by microhardness instrument and image processing method. Rolling contact fatigue life of the coatings is investigated using a RM-1 rolling contact fatigue/wear competitive life test machine, and then the map of Weibull distribution failure probability is plotted. The results show that the quality of Ni60A coatings deposited by supersonic plasma spraying technology can be improved by orthogonal test, four main parameters optimized by orthogonal test is conformed, spraying current is 370 A, spraying voltage is 170 V, argon gas flow rate is 110 L/min, and spraying distance is 110 mm. The microhardness of coatings deposited by optimized parameters is 1 086 HV0.2, and the porosity is 1.05%. Under different contact stress, the contact fatigue life of the Ni60A coatings accords with Weibull distribution, and the rolling contact fatigue life of the coatings under a specific load within a certain range can be predicted.