掺钆铈独居石陶瓷固化体在THMC耦合作用下的化学稳定性  

Chemical Durability of Gd-doped Monazite-Ce Ceramic Form under Coupling Effect of THMC

作　　者：滕元成[1] 杨航[1] 李玉香[1] 吴浪[1] 张魁宝[1] 

机构地区：[1]西南科技大学四川省非金属复合与功能材料重点实验室-省部共建国家重点实验室培育基地,四川绵阳621010

出　　处：《原子能科学技术》2016年第1期18-23,共6页Atomic Energy Science and Technology

基　　金：国家自然科学基金资助项目(11275158);西南科技大学重点科研平台专职科研创新团队建设基金资助项目(14tdfk02)

摘　　要：以氧化钆、十水草酸铈和磷酸二氢铵为原料,采用热压烧结制备掺钆铈独居石陶瓷固化体,借助X射线衍射(XRD)、场发射扫描电镜(FESEM)、能谱(EDS)和电感耦合等离子体发射光谱-质谱(ICP-MS)等分析手段,研究掺钆铈独居石陶瓷固化体的热压烧结及固化体在热-水-力-化学(THMC)耦合作用下的化学稳定性。结果表明,采用热压烧结技术,实现了单相Ce_(0.9)Gd_(0.1)PO_4陶瓷固化体的低温(1 150~1 200℃)、快速(2h)烧结,固化体的相对密度达99.62%;在THMC耦合作用下(温度为90~200℃(0.101~1.554 MPa),pH=5~9),固化体具有优异的化学稳定性,浸出时间为42d时,模拟次锕系核素Gd的归一化浸出率在10^(-6)~10^(-5) g/(m^2·d)数量级;温度和pH值对Ce的归一化浸出率影响较小;温度对Gd的归一化浸出率没有影响;与弱碱性(pH=9)水溶液相比,在弱酸性(pH=5)和中性(pH=7)水溶液中,Gd的归一化浸出率相对较高。The Gd-doped monazite-Ce ceramic forms were prepared by hot-pressing using Ce-2（C-2O-4）-3·10H-2O,NH-4H-2PO-4 and Gd-2O-3as raw materials.The hot-pressing sintering and chemical durability of the ceramic forms under the coupling effect of thermodynamics-hydrodynamics-mechanics-chemistry（THMC）were investigated by means of XRD,FESEM,EDS,ICP-MS and so on.The results show that the single monazitetype Ce0.9Gd0.1PO4 phase is obtained by hot-pressing at 1 150-1 200℃for 2h.The relative density of the ceramic form is 99.62%.Furthermore,the ceramic forms exhibit excellent chemical durability under the coupling effect of THMC（90-200 ℃（0.101-1.554 MPa）,pH=5-9）.The normalized leaching rate（LR）of Gd is 10^-6-10^-5 g/（m^2·d）orders of magnitude on the 42 nd day.Both leaching temperature and pH value have little influence on the LR of Ce,while the leaching temperature has no effect on the LR of Gd.The LR of Gd is relatively higher in weakly acidic（pH=5）and neutral（pH=7）water solution than that in weakly alkaline（pH=9）water solution.

关 键 词：独居石 钆 耦合作用 化学稳定性 热压烧结 

分 类 号：TL941[核科学技术—辐射防护及环境保护]