Gd2-xNdxZr2O7（Nd=An（Ⅲ）, 0≤ x ≤ 2.0）模拟固化体固溶量与其物相、密度、硬度之间的关系

摘要

In order to investigate the capability of Gd2Zr2O7 pyrochlore as a waste form for immobilizing trivalent actinides nuclides, Nd(Ⅲ) is used as an alternative substance for An(Ⅲ). The compounds in the system Gd2-xNdxZr2O7 (0≤ x ≤ 2.0) are synthesized at 1500 ℃ for 72 h by high temperature solid state reaction method, using Gd2O3 and ZrO2 powders as the raw materials. The phase, intensity, Vickers hardness and microcosmic shape are characterized by X-ray diffraction, Vickers hardness tester, scanning electron microscopy and so on. The results indicate that the phase of synthesized waste form with plate-shape keeps the phase of pyrochlore. The intensity of compound slightly decreases with the increase of the containment capacity value x, but it is above 5.76 g·cm-3. The value of Vickers hardness also decreases with the increase of x. The values of x and Vickers hardness are linearly related by HV=695.18636-162.64091 x (HV≥ 400 kg·mm-2).%以Nd（Ⅲ）作为放射性核素An（Ⅲ）的模拟替代物, 以Gd2O3和ZrO2粉体为原料, 通过高温固相反应法（1500 ℃, 保温72 h）合成了Gd2-xNdxZr2O7（0≤ x ≤ 2.0） 微米级的钆锆烧绿石固化An（Ⅲ）的模拟固化体. 利用X射线衍射仪、显微硬度计和扫描电子显微镜等对所制备样品的物相、 密度、维氏硬度和微观形貌进行了表征. 结果表明： Gd2-xNdxZr2O7（0≤ x ≤ 2.0）系列固化体样品多呈板状, 均为烧绿石相; 其密度值随固溶量x值的增加, 呈逐渐下降趋势, 但均 ≥5.76 g·cm-3. 固化体的维氏硬度值（HV）随x值的递增呈逐渐减小趋势, x值与维氏硬度值之间满足HV=695.18636-162.64091 x的线性关系, 但维氏硬度值均≥ 400 kg·mm-2以上.