Dissolution of Impurities Difficult to Solve in Ceramics and the Defect Structures Induced by the Dissolution

为了改善和发展新陶瓷材料的化学、物理和机械性能，有必要阐明特定杂质在这些材料中的作用。高温下陶瓷中的本征缺陷也被认为是难以溶解的杂质. MgO和NiO在尖晶石中的溶解度<Al_2><O_3>用<Al_2><O_3>扩散偶法测定<Al_2><O_3><Al_2>了MgO和NiO<O_3>在<MgAl_2><O_4><NiAl_2>尖晶石中的溶解度<O_4>。测定了镁离子在合金中的杂质扩散系数<Al_2O_3>，并对MgO溶解引入的缺陷结构进行了澄清.本文<Li_2O>提出了一种用X射线衍射技术测定MgO在MgO中低溶解度的新方法<Li_2O>。通过<Li_2O>比较离子电导率和自扩散系数，可以明确MgO溶解的离子电导率<Li_2O>。本文阐明了Th -和-MgO系统的扩散控制蒸发<O_2><UO_2><ZrO_2>。讨论了晶粒快速长大与系统中组元离子扩散的关系<ZrO_2><CeO_2>。

In order to improve and develop chemical, physical, and mechanical properties of new ceramic materials, it is necessary to clarify the functions of specified impurities in those materials. The intrinsic defects in ceramics at high temperatures are also considered as impurities which are difficult to dissolve.1. Dissolution of MgO and NiO in <Al_2> <O_3>The solubilities of MgO and NiO in <Al_2> <O_3> have determined using a diffusion couple of a pure single-crystal <Al_2> <O_3> and polycrystalline <Al_2> <O_3> dispersed with spinel( <MgAl_2> <O_4> or <NiAl_2> <O_4> ). The impurity diffusion coefficient of magnesium ions in <Al_2O_3> has determined and also defect structure introduced by the dissolution of MgO has clarified.2. Defect Structure in <Li_2O>A new method to determine the low solubility of MgO in <Li_2O> by using an X-ray diffraction technique has been developed. Ionic conductivity in MgO-dissolved <Li_2O> could be clarified by comparing the ionic conductivity with self-diffusion coefficients in <Li_2O> .3. Other CeramicsDiffusion-controlled vaporization for the system Th <O_2> - <UO_2> and <ZrO_2> -MgO has been clarified. The relation between the rapid grain growth and the diffusion of the constituent ions in the system <ZrO_2> - <CeO_2> has been discussed.