The vacancy and H interactions in bcc Nb are important due to their implication in understanding of the H induced damage of Nb metallic membrane used in H2 separation and purification application.Using density functio...The vacancy and H interactions in bcc Nb are important due to their implication in understanding of the H induced damage of Nb metallic membrane used in H2 separation and purification application.Using density functional theory,the vacancy formation energy and vacancy(Vac)−H interaction energies are calculated.The results show that vacancies have a strong trapping effect on H atoms,which lowers the formation energy of Vac-nH clusters substantially.The concentration of Vac−nH clusters is evaluated using a statistical model and the dependence of the concentration on the H−to-M ratio is obtained.It is shown that the concentration of the Vac-nH clusters can be as high as 10−3 at 573 K,i.e.one Vac-nH cluster per 1000 atoms,in good agreement with the experimental observations.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 11064004the Natural Science Foundation of Jiangxi Province under Grant No 2010GZW0028.
文摘The vacancy and H interactions in bcc Nb are important due to their implication in understanding of the H induced damage of Nb metallic membrane used in H2 separation and purification application.Using density functional theory,the vacancy formation energy and vacancy(Vac)−H interaction energies are calculated.The results show that vacancies have a strong trapping effect on H atoms,which lowers the formation energy of Vac-nH clusters substantially.The concentration of Vac−nH clusters is evaluated using a statistical model and the dependence of the concentration on the H−to-M ratio is obtained.It is shown that the concentration of the Vac-nH clusters can be as high as 10−3 at 573 K,i.e.one Vac-nH cluster per 1000 atoms,in good agreement with the experimental observations.
