Activation process and absorption/desorption of D2O for Zr-V-Fe getter
Activation process and absorption/desorption of D2O for Zr-V-Fe getter
复制标题
Zr-V-Fe吸气剂的活化过程及D2O的吸附/解吸
DOI：
10.1016/0022-3115(84)90474-4
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发表时间：
1984
影响因子：
3.1
通讯作者：
T. Takeuchi
中科院分区：
文献类型：
--
作者：
K. Ichimura;N. Inoue;K. Ashida;Kuniaki Watanabe;T. Takeuchi
非蒸散型吸气剂在氚处理系统中具有广泛的适用性。从这一观点出发，用XPS-SIMS和质量分析热脱附谱研究了Zr-V-Fe吸气剂（St-707）的活化过程和D_2O在吸气剂表面的吸附/脱附，结果表明，暴露在空气中的吸气剂表面被吸附的H_2O、CO和少量碳氢化合物覆盖，吸气剂组分被氧化。在将吸气剂加热到500 °C以上时，吸附的物质从表面消失，部分是由于解吸，部分是由于迁移到本体中。因此，金属Zr和V出现在表面上，而Fe消失。表面组成被评估为87原子% Zr-13原子% V。在活化之后，水（D2 O）在300 °C下以氘原子的形式容易地被吸收到吸气剂中。吸附速率与水分压成正比，表明吸附的速率决定步骤是表面上水分子的解离。在25和300°C时，吸附速率常数分别为0.009和0.24 cc/s/cm 2（净表面积）[或1.5和39 cc/s/cm 2（投影面积）]。在25 ° C和300 °C下，仅D2从暴露于D2 O的吸气剂解吸。脱附的速率决定步骤是从本体扩散的氘原子在表面上的缔合。
Nonevaporable getters have wide applicability for tritium handling systems. From this view point, the activation process of the Zr-V-Fe getter (St-707) and absorption/desorption of D2O on the getter surface were investigated, by means of XPS-SIMS and mass analyzed thermal desorption spectroscopy.XPS-SIMS measurements revealed that the getter surface exposed to air was covered with adsorbed H2O, CO and small amounts of hydrocarbons and that the getter components are oxidized. Upon heating of the getter above 500 °C, the adsorbed species disappeared from the surface, partly due to desorption and partly due to migration into the bulk. Consequently, metallic Zr and V appeared on the surface, whereas Fe disappeared. The surface composition was evaluated to be 87 at% Zr-13 at% V.After the activation, water (D2O ) was readily absorbed into the getter at 300 °C in the form of deuterium atoms. The absorption rate was proportional to the partial pressure of water, indicating that the rate determining step for the absorption is the dissociation of water molecules on the surface.The absorption rate constant was 0.009 and 0.24 cc/s/cm2(net surface area) [or 1.5 and 39 cc/s/cm2(projected area)] at 25 and 300°C, respectively. Only D2was desorbed from the getter exposed to D2O at 25 and 300 °C. The rate determining step for the desorption is association of deuterium atoms on the surface diffused from the bulk.