D^+注入对Li_4SiO_4表面形貌影响的研究

Effect of Deuterium Ion-Implantation on Surface Microstructures and Deuterium Release Behavior of Li_4SiO_4 Ceramics

国际热核聚变堆采用氚增殖剂与中子反应产生氚,其中氚增殖剂的释放行为和辐照性能是聚变堆设计研究的重要内容,中国独立发展的氦冷固态球床实验包层初步采用硅酸锂作为氚增殖剂。本文采用氢的同位素氘模拟研究氚在增殖剂中的释放行为和辐照性能,通过离子注入方式对硅酸锂陶瓷进行了不同剂量的氘离子辐照,研究了D离子注入对硅酸锂表面形貌的影响,同时采用高温热解析技术研究了D在硅酸锂中的释放行为。结果表明:D离子注入在表面形成了微米级气泡带、纳米级微孔、无规则裂缝。在加热过程中D主要以HD、D_2、HDO、D_2O形态释放。

The experimental simulation was motivated by in-depth understanding of the tritium release behavior of tritium proliferating agent,particularly Li_4SiO_4 ceramic,used to produce tritium via reaction with neutrons in International Thermonuclear Reactors and in China＇s newly-developed tritium-release technique for the pebble bed helium-cooled solid experimental cladding. The impact of the D~＋implantation energy,fluence,time and pressure,on the microstructures,texture and deuterium release behavior of the Li_4SiO_4 ceramic disk,fabricated by solid reaction of highly pure Li_2CO_3 and SiO_2 powders,was investigated with X-ray diffraction,scanning electron microscopy,and quadrupole mass spectroscopy（ QMS）. The results show that the D~＋implantation significantly affected the microstructures and D release behavior. For example,as the D~＋fluence and energy increased,the surface defect density and porosity and roughness increased,forming interconnected D_2 micron-bubbles,sub-micron pores and irregular cracks. Release of HD,D_2,HDO,and D_2O was observed.