微束等离子喷涂Al_2O_3陶瓷涂层特性

Characteristics of Microplasma Spraying of Al_2O_3 Ceramic Coatings

采用轴向中心送粉式微束等离子喷涂系统在2kW级的小功率条件下制备了Al2O3陶瓷涂层。研究了电弧功率、工作气体流量和喷涂距离对粒子速度与涂层组织结构和性能的影响。采用光学显微镜观察涂层的组织结构,采用X射线衍射分析涂层的相结构,采用磨粒磨损质量损失表征涂层的性能,用热辐射粒子速度温度测量系统测试工艺参数对喷涂粒子速度的影响。结果表明,电弧功率、工作气体流量和喷涂距离对粒子速度的影响都比较明显,粒子速度随着电弧功率和工作气体流量的增加而增加,随着喷涂距离的增加而下降。涂层的磨粒磨损质量损失随电弧功率的增加而减少,而随工作气体流量和喷涂距离的增加而增加。分析表明粒子的温度对涂层磨粒磨损质量损失有较大的影响。采用微束等离子喷涂可以制备磨粒磨损性能与传统等离子喷涂在38kW下制备的涂层相当的Al2O3涂层。

Al2O3 coating was deposited by microplasma spraying system through axial powder injection at a low power level about 2 kW. The effects of plasma arc power, operating gas flow and spray distance on particle velocity during spraying, the microstructure and properties of the coatings were investigated. The coating microstructure was examined by optical microscopy, and the coating phase structure was examined by X-ray diffraction analysis. The coating property was characterized by abrasive wear loss. The particle velocity in flight was measured by the particle velocity/temperature measurement system based on thermal radiation. The results showed that the particle velocity was influenced significantly by plasma arc power, operating gas flow and spray distance. The velocity increased with increase of plasma arc power and operating gas flow, decreased with increase of spray distance. On the other hand, the abrasive wear loss of the coatings decreased with the increasing in arc power, and increased with increase of operating gas flow and spray distance. The abrasive wear loss of the coatings was significantly influenced by particle temperature. The abrasive wear loss of the Al2O3 coating deposited by microplasma spraying was comparable to that of the coating deposited by conventional plasma spraying system at 38 kW.