HVOF喷涂参数对WC-Co涂层力学性能的影响

Investigating the Influence of HVOF Parameters on Mechanical Properties of WCCo Coating

目的研究HVO下在不锈钢上热喷涂WC-Co合金涂层喷涂参数如速度和靶距对涂层力学性能的影响,揭示其对表面残余应力,表面硬度的影响机理,优选最佳工艺参数.方法使用HVOF在不锈钢表面喷涂WC-Co合金形成耐磨涂层,通过使用显维硬度测量和钻孔方法来测量不同加工参数下的涂层硬度和残余应力分布.结果涂层和基体上存在3个区域,在这3个区域内硬度和残余应力完全不同的,但它们的变化趋势是一致的.涂层最大硬度并不是在表面,而是距离表面为40μm.结论通过比较不同参数下的涂层力学性能,可以确定最佳加工参数,通过试验发现喷枪速度小,靶矩小,涂层内部残余应力加大,同时显微硬度也有所提高.

High velocity oxyg - fuel （HVOF） technology is used to spray WC- Co alloy and to form a resistance coating on stainless steel. Through experiments with different spraying parameters, such as torch velocity and distance, the influence of parameters on mechanical properties in coating is further studied and the optimal spraying parameters can be selected. The principle of influence on residual stress and hardness in coating is described by changing these parameters. By means of the micro hardness and micro milling methods, the distribution of micro hardness and residual stress in coating are measured under different spraying parameters. The result shows that there are three zones between coating and substrate in which hardness and residual stress are very different under different spaying parameters, but their changing curves are consistent. Comparing mechanical properties on coating under different processing parameters, the optimum parameter is obtained and it is discovered that the smaller the values of torch velocity and the shorter the distances to the workpiece are the higher hardness and larger residual stress are obtained.