二氧化铀芯块低温烧结机理的研究  

Low temperature sintering mechanism on uranium dioxide

作　　者：高家诚[1] 杨晓东[1] 李锐[1] 王勇[1] 钟凤伟[1] 

机构地区：[1]重庆大学材料科学与工程学院,重庆400030

出　　处：《功能材料》2006年第8期1298-1302,共5页Journal of Functional Materials

摘　　要：基于PDM（point defect model），研究了UO2＋x在微氧化性气氛下低温烧结的机理。理论讨论和试验验证了UO2低温烧结时铀离子的体扩散系数、低温烧结温度和致密化动力学方程。结果表明，在UO2中掺入多余氧可使铀离子的扩散激活能降低约3．0eV9铀离子的扩散激系数Dux∝x^2，二氧化铀低温烧结的理论温度约为1089～1151℃，采用UO2＋x坯块是实现低温烧结的必要条件。本模型理论计算的结果与试验数据符合较好，能很好地表征缺陷浓度随气氛变化的特点。Based on point defect model, the mechanism of low-temperature sintering for uranium dioxide was studied in this paper. Diffusion coefficient of uranium in UO2＋x, sintering temperature and densification equation in low temperature sintering were also discussed by both the point defect model and the low-temperature sintering experiments. The resuits show that the diffusion activation energy for uranium in over-stoichiometric UO2＋x is lowered by 3. 0eV than that in stoichiometric UO2, the diffusion coefficient of uranium in UO2＋x is proportional to x^2 , the theory low temperature sintering temperature is about 1089- 1151℃ ,it is necessary to maintain proper over-stoichiometric oxygen for low-temperature sintering process. The theory calculate results by use of the point defect model in this paper are almost accordant with the experiment results from practical low-temperature sintering of uranium dioxide, the point defect model may be good to describe the relationship between the defect concentration and the atmosphere composition.

关 键 词：PDM UO2 低温烧结 机理 核材料 扩散 

分 类 号：TL2[核科学技术—核燃料循环与材料]