氢等离子体作用下的Zr薄膜氢化特性研究

INVESTIGATION ON THE HYDROGENATION PROPERTIES OF Zr FILMS IN PLASMA ACTION

本文研究Zr薄膜在等离子体作用下的氢化特性.测试表明,与分子氢相比,氢等离子体作用下氢化速率明显增高,在室温和≈2Pa氢压的DC放电条件下,氧化10 min样品的氢化浓度可达饱和值,即 66.07（原子分数,％）,远大于该压强下的气体氢化浓度. 在非超清洁系统中,等离子体氢化在样品表面产生大量的氧污染和少量的碳污染.少量的表面氧化物并不阻碍等离子体氢化,但随着污染的增加,氢化浓度却大大减少.Ni对样品表面氢分子解离吸附和氢原子再结合逸出有着不同程度的催化作用,在低的放电压强和放电电流下,表面镀Ni使Zr的稳态氢化浓度减小;而在高压强、低电流下,表面镀Ni可增加 Zr的氢化效率.

The hydrogenation properties of Zr samples with and without Ni overlayer in plasma action were investigated using non-Rutherford backscattering (non-RBS) and elastic recoil detection analysis (ERDA). The theoretical maximum hydrogen capacity, 66.7 (atomic fraction, %), was almost attained when the sample was hydrided at a hydrogen pressure of approximate to2 Pa and a substrate temperature of 393 K for 10 min. This reaction rate is significantly greater than that for gas hydrogenation under the same hydrogen pressure and substrate temperature. It was found that the absorption-of hydrogen is related to C and 0 contamination on the sample surface. Though the oxide layer does not act as a diffusion barrier to atomic hydrogen, the maximum equilibrium hydrogen content dropped drastically with increasing total contamination. Also, the influence of the Ni overlayer on the plasma hydrogenation s discussed. When the sample was hydrided at the relatively low discharge hydrogen pressure (approximate to 2 Pa) and current (approximate to0.025 A), the catalytic effect of the Ni overlayer caused the hydrogen content of the Ni-coated sample to be always a bit less than that of sample without the Ni overlayer. However, the Ni-coated sample demonstrated higher hydriding efficiency when hydried at a higher hydrogen pressure (10-20 Pa) and the same discharge current.