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首页> 外文期刊>Journal of Materials Research >Thermal conductivity of ceramics in the ZrO_2-GdO_(1.5) system
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Thermal conductivity of ceramics in the ZrO_2-GdO_(1.5) system

机译：ZrO_2-GdO_（1.5）系统中陶瓷的导热系数

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摘要

Low thermal conductivity ceramics in the ZrO_2-GdO_(1.5) system have potential in structural (refractories, thermal barrier coatings, thermal protection) and nuclear applications. To that end, the thermal conductivities of hot-pressed xGdO_(1.5) ·(1 - x)Zr0_2 (where x = 0.05, 0.15, 0.31, 0.50, 0.62, 0.75, 0.89, and 1.00) solid solutions were measured, for the first time, as a function of temperature in the range 25 to 700℃. On the ZrO_2-rich side, the thermal conductivity first decreased rapidly with increasing concentration of GdO_(1.5) and then reached a plateau. On the GdO_(1.5)-rich side, the decrease in the thermal conductivity with increasing concentration of ZrO_2 was less pronounced. The thermal conductivity was less sensitive to the composition with increasing temperature. The thermal conductivity of pyrochlore Gd_2Zr_2O_7 (x = 0.5) was higher than that of surrounding compositions at all temperatures. A semiempirical phonon-scattering theory was used to analyze the experimental thermal conductivity data. In the case of pure ZrO_2 and GdO_(1.5), the dependence of the thermal conductivity to the absolute temperature (T) was less than 1/r. Therefore, the minimum thermal conductivity theory was applied, which better described the temperature dependence of the thermal conductivity of pure ZrO_2 and GdO_(1.5). In the case of solid solutions, phonon scattering by cation mass fluctuations and additional scattering by oxygen vacancies on the ZrO_2-rich side and by gadolinium vacancies on the GdO_(1.5)-rich side seemed to account for the composition and temperature dependence of the thermal conductivity.
机译：ZrO_2-GdO_（1.5）系统中的低导热陶瓷具有在结构（耐火材料，隔热涂层，热保护）和核应用方面的潜力。为此，测量了热压xGdO_（1.5）·（1- x）Zr0_2（其中x = 0.05、0.15、0.31、0.50、0.62、0.75、0.89和1.00）固溶体的热导率，第一次，随温度在25到700℃之间变化。在富含ZrO_2的一侧，热导率首先随着GdO_（1.5）浓度的增加而迅速下降，然后达到平稳状态。在富含GdO_（1.5）的一侧，随着ZrO_2浓度的增加，热导率的降低不太明显。随着温度升高，热导率对组合物的敏感性降低。在所有温度下，烧绿石Gd_2Zr_2O_7的热导率（x = 0.5）高于周围组合物的热导率。使用半经验声子散射理论分析实验热导率数据。在纯ZrO_2和GdO_（1.5）的情况下，热导率对绝对温度（T）的依赖性小于1 / r。因此，应用最小热导率理论，可以更好地描述纯ZrO_2和GdO_（1.5）的热导率与温度的关系。在固溶体的情况下，阳离子质量波动引起的声子散射以及富ZrO_2一侧上的氧空位和富GdO_（1.5）一侧上的g空位引起的附加散射似乎都解释了热的组成和温度依赖性电导率。

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