超音速喷涂复合WC基金属陶瓷涂层的性能

Properties of supersonic sprayed composite WC-based cermet coatings

采用超音速火焰喷涂技术和等离子喷涂技术在活塞杆用316L不锈钢基体上制备了WC-12Co(WC)/NiCr双重涂层,并制备传统等离子喷涂Al_(2)O_(3)-13TiO_(2)(AT13)涂层作为对照。通过扫描电镜、X射线衍射仪、显微维氏硬度计、摩擦磨损试验机、电化学工作站等设备对涂层的性能进行了研究和对比。结果表明,各涂层界面界限清晰,结合性良好,WC涂层的显微硬度为1363 HV0.3,是AT13涂层的1.8倍。在60 min往复摩擦磨损试验条件下,AT13涂层的体积磨损率为WC涂层的4.42倍,WC涂层磨损机制主要表现为磨粒磨损。在3.5%NaCl溶液中,WC涂层和AT13涂层的自腐蚀电位均低于316L不锈钢基体,避免了电偶效应对基体的优先腐蚀,并且AT13涂层的自腐蚀电流密度最大,其次是316L不锈钢基体,WC涂层的自腐蚀电流密度最小,仅为基体的0.57倍。

WC-12Co(WC)/NiCr dual coatings and conventional plasma sprayed Al_(2)O_(3)-13TiO_(2)(AT13)coatings were prepared on 316L stainless steel substrate for piston rods by using plasma spraying technology and supersonic flame spraying technology.The properties of coatings were studied and compared by scanning electron microscope,X-ray diffraction,micro Vickers hardness tester,friction and wear testing machine,electrochemical workstation and other equipment.The results show that the interface of each coating has clear boundaries and good bonding.The microhardness of WC coating of 1363 HV0.3 is 1.8 times that of the AT13 coating.Under 60 min reciprocating friction and wear test conditions,the volume wear rate of the AT13 coating is 4.42 times that of the WC coating,and the wear mechanism of the WC coating is mainly abrasive wear.In the 3.5%NaCl solution,the corrosion potentials of both WC coating and AT13 coating are lower than that of the 316L stainless steel substrate,which avoids the preferential corrosion of the substrate by the galvanic coupling effect,and the corrosion current density of the AT13 coating is the largest,followed by 316L stainless steel substrate,while the corrosion current density of WC coating is the smallest,only 0.57 times that of the substrate.