掺Li量和烧结温度对铬酸镧烧结行为的影响

Influence of Li Content and Sintering Temperature on Sintering Behavior of Lanthanum Chromites

研究了用Pechini法制备掺Li铬酸镧超细粉体在烧结过程中掺Li量和烧结温度对粉体烧结行为及烧结体组织的影响。结果表明,在相同烧结温度下,LaCr1-yLiyO3烧结体收缩率随掺Li量的增加而升高;当掺Li量y为0.2时收缩率达到最大;此后随着掺Li量增加而降低。就相同掺Li量的烧结体而言,烧结温度越高组织越致密。致密烧结体的断口特征为穿晶和沿晶混合断裂,这表明晶界结合强度接近晶内。烧结过程中晶粒不断合并、长大,其长大机制为台阶方式。

Superfine powders of Li-doped lanthanum chromites were prepared by Pechini method, and the influence of Li content and sintering temperature on sintering behavior and microstructure was investigated during sintering process. The results show that the shrinkage ratio of LaCr1-yLiyO3 sintered body increases with the Li content y 〈 0.2 at the same sintering temperature, approaches the maximum value near y = 0.20, and then decreases with y 〉 0.2. For the samples with the same Li content, the higher the sintering temperature, the denser the sintered body. The section of sintered bodies shows a mixed mode of transgranular and intergranular fracture, which indicates that the strength of grain boundary is close to that of intracrystalline. The grains grow by step mode, and merge each other during sintering process.