氧化处理时间对Ti6Al4V微弧氧化陶瓷膜的影响

Effect of oxidation time on microarc oxidation ceramic coatings on Ti6Al4V alloy

采用交流微弧氧化法于Na2SiO3-KOH-(NaPO3)6溶液中在Ti6Al4V表面形成了氧化物陶瓷膜.利用扫描电镜、电子探针及X射线衍射研究了陶瓷膜的组织形貌、元素的分布和相组成.研究表明:在恒定的微弧氧化电参数(U+=500V,U-=100V和f=600Hz)下,随氧化时间延长,电流密度逐渐降低,膜层厚度不断增加;相对致密均匀的膜分为3层:过渡层、致密层与疏松层.膜层主要由TiO2(锐钛矿和金红石)相组成,延长处理时间,锐钛矿相及金红石相的相对含量发生变化,金红石相TiO2逐渐增多,而锐钛矿相TiO2减小.膜层相的形成过程可分为两个阶段.

Ceramic oxide coatings were formed on Ti6Al4V alloy surface by microarc oxidation (MAO) in Na2SiO3-KOH-(NaPO3)6solution using an AC power supply. SEM, EPMA and XRD were employed to characterize the microstructure,elements distribution across the coating and phase composition. The results show that with increasing oxidation time, the current density declines gradually and the thickness of ceramic coatings increases with constant electrical parameters (U+=500V, U-=100V and f=600Hz). Relatively dense and uniform coatings consists of three layers: transitional, dense and loose layers, mainly made of anatase and rutile TiO2. As the treatment time prolonged, the relative content of anatase and rutile TiO2 changed, the content of rutile TiO2 increased as anatase TiO2 reduced. A double-stage phase formation mechanism of ceramic coatings was also proposed.