( 1. 中国科学院 兰州化学物理研究所固体润滑国家重点实验室， 兰州 730000；
2. 中国科学院 研究生院， 北京 100039)
摘 要: 在Na3PO4电解液中于恒流条件下对Ti-6Al-4V合金进行了微弧氧化处理， 考察了氧化时间对微弧氧化膜表面形貌、 生长速率、 表面硬度和相组成的影响， 并对不同氧化时间所得微弧氧化膜的摩擦学性能和耐蚀性能进行了表征。研究结果表明： 随着氧化时间的延长， 氧化膜表面微孔孔径逐渐增大， 微孔数量逐渐减少， 氧化膜生长速率逐渐减小， 氧化膜的厚度逐渐增加， 平均表面硬度呈先增大后减小的趋势；微弧氧化膜主要由金红石TiO2和锐钛矿TiO2相组成，随着氧化时间的延长， 金红石相所占比例逐渐增大； 氧化时间的长短对微弧氧化膜的摩擦系数影响不大， 但对其磨损寿命有着显著影响， 延长氧化时间可大大提高微弧氧化膜的磨损寿命，且随着氧化时间的延长， 所得微弧氧化膜的腐蚀电位逐渐增大， 腐蚀电流先减小后增大。
关键字: 微弧氧化； Ti-6Al-4V合金； 结构； 性能
（ 1. State Key Laboratory of Solid Lubrication，
Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences，
Lanzhou 730000，China;
2. Graduate School, Chinese Academy of Sciences, Beijing 100039，China）
Abstract: Ceramic coatings were fabricated on Ti-6Al-4V alloy by micro-arc oxidation(MAO) at the constant current density of 6 A/dm2 in Na3PO4 solution. The effects of oxidation time on the surface morphologies, growth rate, surface roughness, phase composition and surface hardness of the MAO coatings obtained were investigated. Tribological properties and corrosion properties of coatings at different oxidation times were evaluated with the pin-on-disk friction and wear tester and potentiodynamic polarization tester, respectively. The results show that, with the increasing oxidation time, the number of micro-pores and the growth rate of the MAO coatings decrease, while both the size of the micro-pores and the thickness of MAO coating increase. The average surface hardness increases at the initial stage of the oxidation process, then decreases. The MAO coating is mainly composed of rutile TiO2 and anatase TiO2, and the content of rutile TiO2 increases with the increasing oxidation time. Oxidation time has little influence on the friction coefficient of the MAO coatings against GCr15 steel ball, but has much more influence on the wear life of the MAO coatings, the increase of oxidation time can improve wear life. With oxidation time increasing, the corrosion potential of the MAO coating in 3-5% NaCl(mass fraction) solution increases, but its corrosion current firstly decreases, then increases.
Key words: Ti-6Al-4V alloy; micro-arc oxidation; structure; performance
