激光功率对球阀表面激光熔覆Co基合金涂层稀释率及耐腐蚀性能的影响

Effects of Laser Power on Dilution Rate and Corrosion Resistance of Laser Cladding Co-based Alloy Coating on Surface of Ball Valve

采用CO2激光器在阀门材料316不锈钢表面激光熔覆了Co基合金涂层。借助扫描电镜、能谱仪和电化学综合测试仪等,探讨了激光功率对涂层稀释率、微观组织及耐腐蚀性能的影响。结果表明:激光功率越大,涂层稀释率越大,熔覆层与基体元素有较多的对流与扩散;熔覆层的耐腐蚀性能随激光功率的增加先提高后降低,当激光功率为2.1k W时,熔覆层的自腐蚀电位最低,为-0.8456 m V,当激光功率为1.8 k W时,熔覆层的腐蚀电流密度最小(3.4152×10-7A·cm-2)。

Co-based alloy coating was cladded on the surface of 316 stainless steel ball valve materials by CO2 laser. The effects of laser power on dilution rate, microstructure and corrosion resistance of the coating were studied by SEM, EDS and electrochemical measurement. The results show that the high laser power corresponds to the high dilution rate of the coating, larger convection and diffusion is also observed at cladding layer and matrix element. Corrosion resistance of the cladding layer first increases and then decreaseds with the increase of laser power. When the laser power reaches to 2.1 kW, the cladding layer showes a minimum corrosion potential of-0.8456 mV; a minimum cladding corrosion current density of 3.4152×10^-7 A. cm^-2 is observed at a laser power of 1.8 kW.