Study of hydrogen permeation through oxide layer of zircaloy with tritium microautoradiography

用氚显微放射自显影术研究了锆合金表面氧化膜中氚的空间分布。在723 K水蒸汽中对锆合金（Cr2 O3 -2）进行氧化，氧化后，在室温下用氚水通过阴极充电法将氚引入Cr2 O3 -2合金表面的氧化层。用扫描电子显微镜（SEM）观察所形成的氧化膜的表面和横截面的放射自显影。氢在基体合金的晶界和晶内分布较密，而在氧化层中几乎没有分布。氢是局部分布的，但是，在该区域对应的金属间化合物嵌入在氧化物层中的沉淀物。

Spatial distribution of tritium in the oxide layer formed on zirconium alloy was examined by tritium microautoradiography. The zirconium alloy (zircaloy-2) was oxidized in steam at 723 K.After the oxidation, tritium was introduced through the oxide layer formed on zircaloy-2 by the cathodic charging method using tritium water at room temperature. The autoradiographs of the surface and cross-section of the formed oxide films were observed with a scanning electron microscope (SEM). Hydrogen was densely distributed on the grain boundary and in the grain of the inner base alloy, but it was scarcely distributed in the oxide layer. Hydrogen was locally distributed, however, in the region corresponding to the intermetallic precipitates embedded in the oxide layer.