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.