CO_2反应法制备氢化锆表面氢渗透阻挡层的研究

Study on the Hydrogen Permeation Barrier on the Surface of theZirconium Hydride by the Method of CO_2 Reaction.

氢化锆因具备诸多作为反应堆中子慢化材料的优点,有着良好的应用前景。在空间堆中,慢化剂的工作温度范围为650～750℃,而在此温度下,H Zr原子比大于1.8的氢化锆中的氢很容易析出。利用ZrH2和CO2、P反应在氢化锆表面制备氢渗透阻挡层,并借助SEM、XPS和XRD对膜层进行截面形貌观察和物相分析。XRD分析表明氢化锆表面生成了baddeleyite结构的氧化锆。XPS分析表明膜层中含有Zr、C、O、P等元素;窄谱分析还发现膜中生成了C—H键和O—H基团(可能O—H又和锆形成Zr—OH键)。C—H键和O—H基团的存在可能是阻挡氢析出的原因。

Zirconium hydride has excellent practical prospects due to its properties as neutron-moderator material in nuclear reaction piles. Moderators work at temperature between 650℃ and 750℃ in space piles, in this case, zirconium hydride (atom ratio of H/Zr >1.8) loses its hydrogen easily. Hydrogen permeation barrier can be prepared on the surface of zirconium hydride when zirconium hydride reacts with CO_2 and phosphorous red. The cross-sectional morphology and phase structure of the zirconium dioxide film are observed and investigated by the techniques of XPS, SEM and XRD. The XRD results indicate baddeleyite(a kind of ZrO_2-like structure) is obtained on the surface of zirconium hydride. The XPS analysis shows the film includes such elements as zirconium ,oxygen, carbon and phosphor etc. The narrow scan XPS suggests that C-H bonds and O-H groups(O-H groups may form Zr-OH bonds with zirconium) exist in the film. It seems likely that C-H bonds and O-H groups in this film stop hydrogen from escaping outward.