( 1. 哈尔滨工业大学 材料科学与工程学院， 哈尔滨 150001;
2. 西安理工大学 材料科学与工程学院， 西安 710048)
摘 要: 采用常流脉冲控制方式于(NaPO3)6-NaF-NaAlO2溶液中用微弧氧化法在Ti6Al4V表面制备了陶瓷化涂层， 研究了涂层的生长过程及组织结构变化。结果表明： 氧化过程中涂层的生长经历了由快到慢的过程， 在前10min涂层以较快速度生长（约3μm/min）， 随着时间的延长涂层生长速度逐渐减慢； 生长过程中涂层表面微孔数目减少，微孔孔径增大， 涂层表面气孔率增大； 涂层主要由二氧化钛的两种不同变体（锐钛矿及金红石）以及磷化物相AlPO4组成； 随着氧化的进行， 锐钛矿含量降低，金红石含量增加， 氧化过程中发生了锐钛矿相到金红石相的相转变； 结晶AlPO4相是通过水合多聚磷酸铝在放电区附近发生高温热解反应而进入涂层。
关键字: 钛合金； 微弧氧化； 涂层生长； 组织结构
（ 1. School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China;
2. School of Materials Science and Engineering,
Xi′an University of Technology, Xi′an 710048, China）
Abstract: Ceramic coatings were fabricated by microarc oxidation method with a control mode of constant current density on Ti6Al4V alloy in(NaPO3)6-NaF-NaAlO2 solution. The growth process and microstructure variation of microarc oxidation coatings were investigated. The results show that the coatings growth rate is subjected to a variation from rapidness to tardiness during the process. The coating grows rapidly with a rate of approximate 3μm/min within the initial time period of 10min, and followed by a gradually decreasing rate in the later treatment. With increasing treatment time, the micropores number on the surface of the coatings decreases obviously, while the size of micropores increases, as a result, the porosity increases. The coatings are mainly composed of the two modifiers of titanium oxide(namely anatase and rutile) and AlPO4. As the treatment time increases, the anatase content decreses, and the rutile content increases, which indicates that the phase transformation of anatase into rutile occurs during the oxidizing process. The crystalline AlPO4 involves the coatings via high-temperature thermolysis of hydrated aluminium polyphosphates in the near channel zone of microdischarging.
Key words: titanium alloy; microarc oxidation; coatings growth; microstructure
