Surface Segregation of Ti in a V-4Cr-4Ti Alloy and Its Influence on the Surface Reaction Rates of Hydrogen Isotopes
Surface Segregation of Ti in a V-4Cr-4Ti Alloy and Its Influence on the Surface Reaction Rates of Hydrogen Isotopes
复制标题
DOI：
10.2320/matertrans.46.511
复制
发表时间：
2005-03
影响因子：
1.2
通讯作者：
Y. Hatano;R. Hayakawa;K. Nishino;S. Ikeno;T. Nagasaka;T. Muroga;Kuniaki Watanabe
中科院分区：
文献类型：
--
作者：
Y. Hatano;R. Hayakawa;K. Nishino;S. Ikeno;T. Nagasaka;T. Muroga;Kuniaki Watanabe
用X射线光电子能谱研究了V-4Cr-4 Ti合金在573 ~ 1273 K真空热处理后表面化学状态的变化。在加热之前，抛光合金的表面覆盖有V氧化物膜。氧在673 K左右开始扩散到合金中，合金表面逐渐变成金属化。然而，氧气并没有完全从表面消失。随着温度的升高，观察到Ti的表面偏析。在1273 K时Ti的含量达到20 at%。未观察到Cr或其他杂质的显著偏析。Ti的这种表面偏析显著降低了H2和D2的表面反应速率。在本实验条件下，未观察到H_2和D_2表面反应速率的同位素效应。
The change in the chemical surface state of a V-4Cr-4Ti alloy after heat treatments in vacuum at temperatures from 573 to 1273 K was investigated by means of X-ray photoelectron spectroscopy. Before heating, the surface of the as-polished alloy was covered with a V oxide film. Diffusion of oxygen into the bulk started at around 673 K, and the alloy surface gradually became metallic. Oxygen, however, did not disappear from the surface completely. Surface segregation of Ti was observed as the temperature increased. The concentration of Ti reached 20 at% at 1273 K. No significant segregation of Cr or other impurities were observed. This surface segregation of Ti significantly reduced the surface reaction rates of H2 and D2. The isotope effect on the surface reaction rates of H2 and D2 was not observed under the present experimental conditions.