Liu Hao, Chen Ping-Hu, Chen Yong, Wu Wen-Xing, Li Sheng, Qiu Chang-Jun
School of Resource Environment and Safety Engineering, College of Mechanical Engineering, School of Nuclear Science and Technology, University of South China, Hengyang 421001, China.
College of Mechatronics & Control Engineering, Shenzhen University, Shenzhen 518060, China.
Materials (Basel). 2022 Aug 8;15(15):5443. doi: 10.3390/ma15155443.
The effects of laser parameters on the microstructure and properties of plasma-sprayed yttrium oxide coating on the graphite matrix were investigated. Tensile strength, porosity, roughness, and scratch meter tests were carried out to evaluate the critical load and mechanical properties of the coating after spraying and laser micro-melting. When the porosity and surface roughness of the coating are minimum, the critical load of the coating is 7.85 N higher than that of the spraying surface. After laser micromelting, the crystal phase of YO coating surface does not change, the crystallinity is improved, and fine grain strengthening occurs. When the laser power density is 75 W/mm, the scanning speed is 30 mm/s, and the defocusing distance is 40 mm, the film base bonding performance and wear resistance of the material reach the maximum value. The failure of YO coating is mainly due to the degradation of mechanical properties such as film base bonding strength, surface porosity, and surface roughness, which leads to the local collapse of the material. The coating after laser micro-melting only presents particle disintegration at the end of the scratch area.
研究了激光参数对石墨基体上等离子喷涂氧化钇涂层微观结构和性能的影响。进行了拉伸强度、孔隙率、粗糙度和划痕仪测试，以评估喷涂和激光微熔后涂层的临界载荷和力学性能。当涂层的孔隙率和表面粗糙度最小时，涂层的临界载荷比喷涂表面高7.85 N。激光微熔后，YO涂层表面的晶相不变，结晶度提高，发生细晶强化。当激光功率密度为75 W/mm、扫描速度为30 mm/s、离焦距离为40 mm时，材料的膜基结合性能和耐磨性达到最大值。YO涂层的失效主要是由于膜基结合强度、表面孔隙率和表面粗糙度等力学性能的退化，导致材料局部塌陷。激光微熔后的涂层仅在划痕区域末端出现颗粒崩解。
