热氧化处理钛表面渗氧层的组织与性能研究

Characterization of the Surface Oxygen-Diffusion Zone of the Thermally Oxidized Titanium

商业用纯钛在空气炉中700℃~900℃,1 h^4 h 进行热氧化处理,得到由氧化层和渗氧层构成的表面结构。通过金相观察、显微硬度测试、X 射线衍射(XRD)及扫描电镜(SEM)分析,研究了渗氧层的结构和性能。结果表明,经一定温度及时间处理,试样渗氧层被一条连续的界线分为内渗氧层和外渗氧层,在光学显微镜下观察,内外两层渗氧层形貌无差别,但在扫描电镜下观察可发现在较高温度形成的外渗氧层较疏松,内渗氧层则仍致密。随着热处理温度的升高、时间的延长,渗氧层厚度和含氧量增加,晶格常数c 伸长,表面硬度显著增大。

After thermal oxidation at 700 degrees C similar to 900 degrees C for 1 h similar to 4 h in air, a surface structure composed of titanium dioxide layer and underlying oxygen-diffusion zone was formed on commercially pure titanium. By means of optical microscopy, microhardness testing, X-ray diffractometry (XRD) and scanning electron microscopy (SEM), the oxygen-diffusion zone was characterized in the present paper. The diffusion zone consists of an inner zone and an outer zone, which are separated by a continuous boundary line. The outer zone appears to be less dense than the inner zone as the oxidation temperature is higher. The oxygen concentration of the diffusion zone increase with increasing treatment temperature and period of time, resulting in significant distortion of the c parameter of alpha-Ti and subsequently hardening of the oxygen diffusion zone.