氧化镧对镁橄榄石晶体结构及性能的影响(英文)  

Influence of La_2O_3 on the Crystalline Structure and Property of Forsterite

作　　者：罗旭东[1,2] 曲殿利[1] 谢志鹏[2] 秦彬[1] 宋阳[1] 

机构地区：[1]辽宁科技大学高温材料与镁资源工程学院,鞍山114051 [2]清华大学材料科学与工程系新型陶瓷与精细工艺国家重点实验室,北京100084

出　　处：《硅酸盐通报》2013年第9期1709-1713,1718,共6页Bulletin of the Chinese Ceramic Society

基　　金：Key Project in the National Science and Technology Pilar Program during the Twelfth Five-year Plan Period(2012BAB06B00)

摘　　要：以低品位菱镁矿与天然硅石为原料,以氧化镧为添加剂,通过固相反应烧结制备镁橄榄石。研究讨论了氧化镧对镁橄榄石材料相组成、晶胞参数、微观结构及常温性能的影响。用XRD和SEM法对烧后试样的相组成和显微结构进行研究。利用X’pert plus软件对试样中镁橄榄石相的晶胞参数进行计算。按国家标准,检测镁橄榄石试样的体积密度、显气孔率、吸水率和常温耐压强度。结果表明:加入适量氧化镧可以促进了低品位菱镁矿轻烧氧化镁粉与天然硅石中通过固相反应烧结合成制备镁橄榄石。氧化镧加入量为1.2%时,镁橄榄石的晶胞体积最大,镁橄榄石中引入氧化镧所造成的结构缺陷加速了离子扩散速度,而过量的氧化镧会进入晶界液相中。综合以上分析,氧化镧的引入量为1.2%时,镁橄榄石材料综合性能最好,其体积密度为2.44 g/cm3,显气孔率为23%,吸水率为9.5%,常温耐压强度为30.1 MPa。The influence of La203 on the crystalline structure of forsterite synthesized from low-grade magnesite and natural silica is discussed. X-ray diffraction （XRD） and scanning electron microscopy （SEM） were employed to characterize the crystalline structure and microstructure of each specimen. X＇ Pert plus software was used to determine the lattice parameters of each specimen. Bulk density, apparent porosity, water absorption and cold crush strength of the test samples were tested according to standards issued by the ministry. The results show that appropriate La203 addition is helpful to form forsterite. When the addition of La203 is 1.2wt%, the cell bulk of forsterite reaches the highest, the defects caused by La203 accelerate the diffusion rate of the cations. Excess La203 will solve into the liquid on the grain boundary. In combination of XRD, SEM and property analysis results, the optimal addition of La203 is determined to be 1.2%. Corresponding, bulk density is 2.44 g/cm^3 , apparent porosity is 23%, water absorption is 9.5% and cold crush strength is 30.1 MPa.

关 键 词：低品位菱镁矿 天然硅石 镁橄榄石 氧化镧 

分 类 号：O76[理学—晶体学]