钙掺杂对铬酸镧热膨胀系数的影响  

Effect of Ca-Doping on Coefficient of Thermal Expansion of Lanthanum Chromites

作　　者：谭威[1] 林旭平[1] 艾德生[1] 马景陶[1] 邓长生[1] 徐景明[1] 

机构地区：[1]清华大学核能与新能源技术研究院精细陶瓷北京市重点实验室新型陶瓷与精细工艺国家重点实验室,北京100084

出　　处：《硅酸盐学报》2012年第6期839-843,共5页Journal of The Chinese Ceramic Society

基　　金：国家重大科技专项(2010ZX06901–020);清华大学自主科研计划(20101081790)资助项目

摘　　要：利用固相法合成的铬酸镧粉制备铬酸镧样品。研究了钙掺杂量对铬酸镧样品热膨胀系数的影响。结果表明:当钙掺杂铬酸镧时,Ca2+于A位取代La3+,引起A位离子半径减小,晶胞参数发生变化,同时Cr3+变价形成Cr4+,引起了O2–—O2–和Cr3+—O2–键长、键角和键能相应改变,从而对铬酸镧样品的热膨胀系数和相变温度造成影响;从室温到1000℃,铬酸镧的热膨胀系数随钙掺杂量增加而增大,由正交结构向菱形结构转变的相变温度随钙掺杂量增加呈线性提高。The lanthanum chromites samples were prepared by the powders synthesized by a solid-state reaction. The effect of Ca-doping on coefficient of thermal expansion（CTE） of lanthanum chromites was studied. The results showed that with the Ca-doping, A site atom La^3＋ in the LaCrO3 would be replaced by the Ca^2＋, the radius of A site was reduced and crystal parameter was changed. At the same time, the bond length, bond angel and bond energy of O^2--O^2-, Cr^3--O^2- were changed due to the changing of Cr^3＋ to Cr^4＋. Between room temperature to 1 000 ℃, the CTE of lanthanum chromites increased with the increase of Ca-doping content, also the phase transformation temperature of lanthanum chromites from the orthogonal structure to rhombic structure linearly increased with Ca-doping content.

关 键 词：铬酸镧 钙 掺杂 热膨胀系数 

分 类 号：TQ174.7[化学工程—陶瓷工业]