激光熔覆NiCoCrAlY/ZrB_2复合涂层结构及高温耐磨性能

Microstructure and High Temperature Wear Resistance of Laser Cladding NiCoCrAlY/ZrB_2 Coating

通过激光熔覆技术在钛表面成功制备了NiCoCrAlY和NiCoCrAlY/ZrB2复合涂层,用SEM和XRD分析了涂层的组成及结构。在SRV-IV高温摩擦磨损试验机上系统考察了NiCoCrAlY和NiCoCrAlY/ZrB2复合涂层在20、100、300和500℃下的摩擦磨损性能,对偶为Si3N4陶瓷球。采用SEM和3D非接触式表面轮廓仪磨损形貌分析了摩擦磨损测试后涂层和对偶陶瓷球的磨痕形貌。结果表明:NiCoCrAlY/ZrB2复合涂层相对于NiCoCrAlY涂层有更高的显微硬度和更好的高温耐磨性能,NiCoCrAlY和NiCoCrAlY/ZrB2复合涂层在不同温度下的磨损机理主要为磨粒磨损和粘着磨损。

NiCoCrAlY and NiCoCrAlY/ZrB2 coatings were prepared on pure Ti substrates by the laser cladding technique. The compositions and the microstructure of the prepared coatings were analyzed by scanning electron microscopy （SEM） and X-ray dif- fraction （XRD）. The tribological properties were tested through sliding against Si3N4 balls at the temperatures of 20, 100, 300 and 500 ℃. Besides, the morphologies of the worn surfaces and wear debris were analyzed by scanning electron microscopy （SEM） and three dimensional （3D） non-contact surface mapping. The results show that the NiCoCrAlY/ZrB2 composite coating has higher mi- crohardness and excellent high-temperature wear resistance than NiCoCrAlY coating. The wear mechanism for NiCoCrAlY and NiCoCrAlY/ZrB2 coatings versus silicon nitride at elevated temperatures is abrasive and adhesive wear.