La_2O_3含量对Ta_2O_5-La_2O_3体系陶瓷结构与性能的影响  

Influence of La_2O_3 Content on Microstructure and Properties of Ta_2O_5-La_2O_3 System Ceramics

作　　者：巫春荣[1] 张小珍[1] 周健儿[1] 江瑜华[1] 李月明[1] 

机构地区：[1]景德镇陶瓷学院材料科学与工程学院,江西省先进陶瓷材料重点实验室,江西景德镇333403

出　　处：《陶瓷学报》2014年第3期260-264,共5页Journal of Ceramics

基　　金：国家科技支撑计划课题(编号:2011BAC11B08);江西省科技支撑计划项目(编号:20112BBE5009)

摘　　要：采用干压成型和高温固相反应烧结法制备了Ta2O5-La2O3体系陶瓷材料。研究了La2O3含量对制备的样品的物相组成、微观结构、热膨胀系数和抗弯强度等的影响。结果表明:纯Ta2O5陶瓷由斜方相Ta2O5组成,存在明显的开裂现象,表现出低的抗弯强度和负的低热膨胀系数。加入5%La2O3时,样品主要由斜方相Ta2O5组成,还生成了少量斜方相LaTa7O19。LaTa7O19晶相含量随La2O3含量增加而增大,加入量为12.5%时,样品主要由LaTa7O19针状晶体组成。适量La2O3加入可有效抑制烧成过程中Ta2O5晶粒增长和避免开裂现象,样品表现出较小的正的热膨胀系数,抗弯强度显著提高。La2O3含量为5%时,在1400℃保温2 h烧成制备的样品的热膨胀系数和抗弯强度分别为3.4×10-6℃-1和81.4 MPa。Ta2O5-La2O3 system ceramic materials were prepared by dry pressing and high temperature solid-state reaction sintering techniques. The influences of La2O3 content on the phase composition, microstructure, thermal expansion coefficient（TEC） and bending strength of prepared ceramic samples were investigated. Results show that the pure Ta2O5 ceramic, composed of orthorhombic phase Ta2O5,shows obvious microcracking phenomena and exhibits low bending strength and low negative thermal expansion coefficient. Orthorhombic phase LaTa7O19 acicular crystals as minor phase were formed with the addition of 5% La2O3. The amount of LaTa7O19 crystalline phase increases with the increment of La2O3 content, and the sample with 12.5% La2O3 is mainly composed of LaTa7O19 crystalline phase. The addition of small quantity of La2O3 could effectively inhibit the growth of Ta2O5 grains and avoid the generation of microcracks. Low positive TEC and increased bending strength could be obtained for Ta2O5-La2O3 system ceramic with 3% and 5% La2O3. The sample with 5% La2O3 shows a TEC of 3.4×10^-6 ℃^-1 and bending strength of 81.4 MPa sintered at 1400 ℃for 2 h.

关 键 词：低膨胀陶瓷 氧化镧 热膨胀系数 抗弯强度 

分 类 号：TQ174.75[化学工程—陶瓷工业]