离子注入对TC4钛合金TiN/Ti涂层结合力和抗砂尘冲蚀性能的影响

目的通过离子注入提高TiN/Ti涂层的结合力和抗冲蚀性能。方法先采用金属蒸气真空弧(MEVVA)离子源在TC4基体上分别注入四种离子(Mo、Ti、Nb、Co),再用磁过滤真空阴极弧(FCVA)技术制备TiN/Ti涂层。采用非球面测量仪、AFM、XRD和纳米压痕仪,对四种离子注入的TC4基体表面粗糙度、表面形貌、物相结构、纳米硬度和弹性模量进行表征,采用划痕仪测量涂层的结合力,采用涂层冲蚀考核平台对不同试样进行砂尘冲蚀性能试验。结果经过Mo、Ti、Nb离子注入的TiN/Ti涂层的结合力和抗冲蚀性能都有提高,其中Mo离子注入的TiN/Ti涂层的结合力达71 N、耐冲蚀时间为80 min,与未离子注入涂层相比,分别增加31.5%和77.8%,而平均冲蚀率降低39.5%,仅为0.0078mg/g。Co离子注入的TiN/Ti涂层的结合力仅为40 N,平均冲蚀率增大了19.0%,达0.0433 mg/g,其抗砂尘冲蚀性能明显下降。结论离子注入涂层的抗砂尘冲蚀性能与结合力密切相关,随着结合力的增大,TiN/Ti涂层的平均冲蚀率减小,其耐冲蚀时间增加,选择合适的离子注入可提高TiN/Ti涂层的抗冲蚀性能。

Effects of Ions Implantation on Adhesion Strength and Sand Erosion Resistance of TiN/Ti Coatings on TC4 Titanium Alloy

The work aims to improve the adhesion strength and erosion resistance of TiN/Ti coatings with ion implantation. Firstly, four different kinds of ions (Mo, Ti, Nb, Co) were implanted into TC4 substrates by metal vapor vacuum arc (MEVVA) technology, respectively. Then, TiN/Ti coatings were deposited on these TC4 substrates by FCVA. The surface roughness, surface morphology, phase structure, nano-hardness and elastic modulus of these TC4 substrates were characterized by aspheric surface measuring instrument, SEM, AFM, XRD and nano-indenter. The adhesion strength of the coatings to TC4 substrates was assessed by a scratch tester. The performance of sand erosion resistance of different samples was evaluated by the coating erosion test platform. The adhesion strength and erosion resistance of TiN/Ti coatings were improved after Mo, Ti and Nb ion implantation. Compared with the non-implanted coatings, the adhesion strength and the erosion resistance time of TiN/Ti coatings implanted by Mo ion were 71 N and 80 min, which increased by 31.5% and 77.8%, respectively. The average erosion rate of these coatings was 0.0078 mg/g, reduced by 39.5%. The adhesion strength of TiN/Ti coatings implanted with Co ion was only 40 N and the average erosion rate was 0.0433 mg/g, increased by 19.0%, and the erosion resistance decreased significantly. The sand erosion resistance of the ion implanted coatings is closely related to the adhesion strength. With the increase of the adhesion strength, the average erosion rate of TiN/Ti coatings decreases, and erosion time increases. Therefore, appropriate ion implantation can improve the erosion resistance of TiN/Ti coatings.