Trial Fabrication and Properties of Ceramic Coatings for Fusion Reactor

在聚变堆液体包层陶瓷涂层中，有一些重要的因素，如批量生产，与液态金属的兼容性，以及作为氚渗透屏障和绝缘屏障的功能。本研究选择了几种陶瓷涂层的候选材料，并对这些材料进行了实验性的涂层制备，研究了它们的特性，为建立聚变堆液体包层陶瓷涂层的制备技术奠定了基础。结果总结如下。(1)陶瓷涂层材料的选择：对于Li 17-Pb 83，根据热化学分析和块体材料腐蚀试验，选择Al_2O_3、MgO、Y_2O_3作为候选材料，其中Al_2O_3和Y_2O_3的电绝缘性能上级，被选为首选材料。对于金属锂，除Y_2O_3外，没有发现其它耐腐蚀的氧化物，而AlN被选为候选物 ...更多信息 还检查了氮化物之后的材料。(2)陶瓷涂层材料在聚变堆环境中的性能变化：我们测量了所选材料在液态金属腐蚀试验后的电性能。Y_2O_3被锂还原，形成非化学计量比的化合物而导电。高温辐照下，涂层的电阻率会因辐照诱导导电而降低。(3)陶瓷涂层的试制及性能评价：在此基础上，采用多种方法制备了Al_2O_3、Y_2O_3、AlN陶瓷涂层，并对其性能进行了测试。关于等离子喷涂方法，生成率足够高，但如何才能去除内部气孔是一个重要问题。关于浸涂方法，如何有效地氮化试样是一个重要的问题，特别是在AlN涂层的情况下。在溅射法中，对基体的处理是必要的，最后得出目前最理想的镀膜方法是浸涂法。另一方面，对于金属锂，其是通过溅射或CVD法形成AlN层，通过浸涂法或溅射形成Al层。少

In ceramic coating for fusion reactor liquid blankets, there are some important factors such as mass-production, compatibility with liquid metal and function as a tritium permeation barrier and an insulating barrier. In this study, we selected some candidate materials for ceramic coating, produced coatings experimentally from those materials, and investigated their characteristics so that we might establish the fabrication technique of ceramic coating for fusion reactor liquid blankets. The results are summarized as follows.(1) Material selection for ceramic coating : For Li17-Pb83, Al_2O_3, MgO, Y_2O_3 were nominated for candidate material based on thermochemical analysis and the corrosion test using bulk materials, and Al_2O_3 and Y_2O_3 were selected as the primary candidate materials because their electric insulation property was superior among them. For metallic lithium, on the other hand, no corrosion resistant oxides were found except Y_2O_3, and AlN was selected as a candidate … More material after nitrides were also examined.(2) Property change of ceramic coating materials in the fusion reactor environment : We measured electrical properties of the materials that were thus selected after corrosion test with the liquid metals. Y_2O_3 was reduced by lithium to become electrically conductive due to the formation of a nonstoichiometric compound. It was also concluded that the electrical resistivity of coatings may deteriorate due to radiation induced conduction under irradiation at high temperature.(3) Trial fabrication of ceramic coatings and assessment about their utility : Based on the results mentioned above, we prepared ceramic coatings of Al_2O_3, Y_2O_3, AIN by some methods and measured their properties. About the plasma spraying method, generation rate was enough high, but how you can remove inside pores is an important problem. About the dip coating method, how you can effectively nitrify the specimens is an important problem, in particular in case of AlN coating. In the sputtering method, it was concluded that the treatment of substrate is necessary.Finally, it was concluded that the most desirable method for coating at present is the dip coating method of Al_2O_3 for Li17-Pb83. For metallic lithium, on the other hand, it is AlN layer formation by sputtering or the CVD method Al layer formed by the dip coating method or sputtering. Less