氧化铌对原位合成钛酸铝自增韧结构的影响

Effect of Nb_2O_5 Additive on the In-Situ Formation of Al_2TiO_5 Ceramic with Self-Toughening Microstructure

为探讨采用反应烧结原位合成途径制备自增韧钛酸铝陶瓷的可能性,通过对机械激活、Nb_2O_5为添加成分的反应前驱体在1300～1500℃之间的反应烧结,对比分析了不同烧结温度下的成分和结构的变化,并在1500℃、烧结时间3 h的条件下原位合成了具有自增韧结构的钛酸铝陶瓷。高温下由Nb_2O_5产生的液相以及Nb^(5+)对钛酸铝晶格离子的置换效应对各向异性晶粒生长和自增韧结构的形成起到重要作用。

The purpose of this work is to study the preparation possibility of self-toughening Al2TiO5 ceramic by in situ solid-state reaction sintering route. The mechanical activated precursors were sintered at 1300 ℃ and 1500 ℃, with Nb2O5 as additive. The evolvements of chemical composition and microstructural characteristic were studied contrastively related to different sintering conditions. Al2TiO5 ceramic with self-toughening microstructure was produced under the reaction sintering condition of 1500 ℃ for 3 h. The liquid phase derived from Nb2O5 melt and the replacement of Nb^5＋ in Al2TiO5 were found to be much important for the anisotropic grain growth and self-toughening microstructure formation of the Al2TiO5 ceramic at elevated temperature.