316L钢表面超音速火焰喷涂Fe基粉末涂层显微结构及摩擦性能分析

经过液氮循环工艺获得了塑韧性更优的Fe基粉末，通过超音速火焰喷涂（high velocity oxy-fuel，HVOF）法对建筑用316L钢基体表面造成高速撞击生成Fe基粉末涂层，分析涂层摩擦学特性与液氮循环工艺间的关系。研究结果表明:液氮循环处理粉末和未处理原始粉末都属于非晶态，粉末外观形貌都属于椭球形，没有开裂或破碎。在液氮循环处理粉末涂层组织中只存在少量的未铺展颗粒，孔隙率也发生了明显减小，形成了更致密组织。采用液氮循环方法来改善粉末塑性，使粉末以更好的铺展状态完成沉积过程。经过液氮循环处理的粉末涂层可以获得更稳定的摩擦学性能，形成了更致密的组织，孔隙与裂纹数量明显降低，摩擦系数明显减小，主要发生氧化磨损，表现出更低的磨痕深度与磨损率误差。

Analysis of microstructure and friction property on 316L steels coated with Fe-based powders by high velocity oxy-fuel

The Fe-based powders with the better plasticity and toughness were obtained by liquid nitrogen cycling, the Fe-based powder coatings were generated by high-speed impact on the substrate surface of 316L steels used for building using the high velocity oxy-fuel method, and the relationship between the coating tribological characteristics and the liquid nitrogen cycling was analyzed. The results show that, both the powders treated by liquid nitrogen cycling and the untreated original powders are amorphous, and the appearance morphology of the powders belongs to ellipsoid without the causing cracking or crushing. After the liquid nitrogen cycle treatment, only a small number of the undispersed particles exist in the powder coating tissues, and the porosity also decreases significantly, forming a denser tissue. The liquid nitrogen cycle method can be used to improve the plasticity of powders, and the powders can be deposited in a better spreading state. The powder coatings after the liquid nitrogen cycle treatment can obtain the more stable tribological properties and show the denser structure, the number of pores and cracks reduces significantly, the friction coefficient decreases obviously, the oxidation wear mainly occurs, and the wear depth and the wear rate error are lower.