掺钛UO_2微球烧结行为研究

Study on Sintering Behavior of UO_2 Microsphere Doped with Titanium

采用溶胶-凝胶方法制备掺钛UO2微球,并通过金相显微镜、扫描电镜（SEM）、能谱分析仪（EDS）等观察掺钛微球的微观组织、气孔分布、晶粒大小、钛元素分布以及用水浸渍法测量其密度。实验结果表明：在一定烧结温度下,掺入少量钛可明显提高烧结性能。在实验条件下,最佳掺钛量为0.3%（质量分数）以内、烧结温度为1250~1350℃。研究了活化烧结机制,得出其物质迁移机制可能为加强阳离子扩散和剩余氧共同作用的结果;最后研究了钛元素的分布,除固溶于UO2微球外,其他钛氧化物以游离相粒子形式富集在晶界上。

This paper studies the preparation of titanium（Ti） UO2 microspheres by sel-gol method,and its microstructure,pore distribution and grain size are observed by optical microscope,SEM and EDS.Its density is measured by water immersion method.The results show that doping small amount of titanium can significantly improve the sintering behavior at a certain sintering temperature.In this study,the optimal doping content of Ti is within 0.3% wt and the best sintering temperature is 1250-1350℃.This paper also studies the activated sintering mechanism,with a conclusion that the material transfer mechanism may enhance the cation diffusion,and residual oxygen interaction.Additionally,it studies the distribution of titanium in the microspheres.Besides the solid solution of titanium in UO2 microspheres,the redundant enriches in the grain boundary in the form of free particles.