Study on Liquid-Phase-Assisted Laser Surface Microtexturing and the Surface Properties of 304 Stainless Steel

Because of its high processing efficiency and good processing quality, laser surface microtexturing technology can effectively improve the surface hardness and wear resistance of materials. However, traditional laser microtexture processing is mostly performed in an air medium, in which the oxygen in the air easily oxidizes the material surface, and the molten material generated during laser processing can easily be recast on the surface, affecting its surface texture quality. In the study presented in this paper, liquid-phase-assisted laser processing technology was used for the surface microtexturing of 304 stainless steel. Grooves and round lattice were processed in air, distilled water and sodium bicarbonate solution. The surface properties of the texture were characterized by scanning electron microscopy (SEM), white-light interferometry, contact angle measurement, micro-Vickers hardness testing and Bruker UMT-TriboLab friction testing. The results show that the surface of the sample processed by liquid-phase-assisted laser processing technology was flatter and that the texture formation effect was better. Under liquid-phase-assisted conditions, the wettability of the textured surface improved, and the contact angle was reduced by 38.8%. The hardness distribution of the textured surface was relatively uniform under this condition. The friction test results show that the textured surface wear mark is smaller and the wear resistance is significantly improved with liquid-phase-assisted laser processing.