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采用等离子喷涂与激光渗氮技术相结合的工艺方法,在Ti6Al4V合金表面实现了TiN/Ti3Al金属间化合物复合涂层的快速制备。首先在Ti6Al4V基体表面利用等离子喷涂的方法预置一层纯铝涂层;然后在纯氮环境下,利用激光渗氮化技术对试样表面进行合金化处理。采用扫描电镜(SEM)、X射线衍射(XRD)等试验手段,研究了氮气流量以及激光扫描速度两个激光渗氮工艺参数对TiN/Ti3Al金属间化合物复合涂层的微观组织的影响。结果表明,复合涂层中TiN相的含量随着氮气流量的增加与激光扫描速度的减小而增加。工艺参数对涂层中TiN增强相的形貌有着重要影响。在高氮气流量、低激光扫描速度条件下制备出的涂层中,TiN相呈颗粒状。对于低氮气流量、高激光扫描速度条件下,TiN增强相呈树枝状。
The preparation of TiN / Ti3Al intermetallic compound coating on Ti6Al4V alloy was achieved by the combination of plasma spraying and laser nitriding technology. First of all, a layer of pure aluminum coating is pre-deposited on the surface of Ti6Al4V substrate by plasma spraying method; then, the surface of the sample is allotted by laser nitriding technology under pure nitrogen environment. The microstructure of the TiN / Ti3Al intermetallic compound coating was investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of nitrogen gas flow rate and laser scanning speed on the microstructure of TiN / Ti3Al intermetallic compound coating were studied. The results show that the content of TiN phase in the composite coating increases with the increase of nitrogen flow rate and the decrease of laser scanning speed. The process parameters have an important influence on the morphology of the TiN-enhanced phase in the coating. The TiN phase is grainy in coatings prepared under high nitrogen flow rates and low laser scanning speeds. For low nitrogen flow rates and high laser scanning speed, the TiN reinforcing phase is dendritic.