关键词: 纳米η-Al₂O₃, 铝铬固溶体, 固相烧结, 烧结助剂, 晶粒生长, 烧结动力学

Abstract: Aluminum chromium solid solution is widely used in refractory materials, but it’s hard to achieve sintering and densification. Adding a certain amount of sintering additives can effectively improve its density, but the rule of grain growth in the densification process is still unclear. In this experiment, nano η-Al₂O₃ and industrial chromium green were used as raw materials, with TiO₂ as sintering aid and PVA as the binder, after being formed by cold isostatic pressing, the sintered aluminum chromium solid solution with the mole ratio of 1∶1 was prepared by solid phase sintering at 1 400 ℃ to 1 700 ℃ under normal pressure. The density, phase composition, microstructure, and average grain size of the sintered samples were analyzed by Archimedes method, XRD, SEM, and Nano measurer. On this basis, the effect of TiO₂ on sintering kinetics of aluminum chromium solid solution was further calculated and studied. The results show that during the sintering process, the grain growth index and activation energy of Al₂O₃-Cr₂O₃ and Al₂O₃-Cr₂O₃-2%TiO₂ sintered systems decrease with the increase of temperature. The grain growth of Al₂O₃-Cr₂O₃ system is mainly controlled by atoms crossing grain boundaries randomly and volume diffusion, the grain growth of the Al₂O₃-Cr₂O₃-2%TiO₂ system is mainly controlled by volume diffusion. Compared with the two systems, it is found that the addition of TiO₂ can decrease the grain growth index and activation energy of grain growth, and promote the grain growth and its development.

Key words: nano-η-Al₂O₃, aluminum chromium solid solution, solid phase sintering, sintering additive, grain growth, sintering kinetics