Solid-State Conversion Technology Of Single-Crystal Oxide

This work is concentrated on the study of solid-state conversion of single-crystal alumina. Effect of the average size of high purity alumina power and additive systems on the alumina grain growth and optical transmission was investigated. Morphology and phase analysis of alumina were observation. Optical transmission of alumina was measured.The results indicated that the average size of alumina powder can directly affect the size of the alumina grain growth. The smaller the average size of alumina powder can promote the growth of abnormal grain. Effect of additive systems on solid-state conversion of single-crystal alumina is different. MgO can improve the optical transmission of alumina. SiO₂ can cause abnormal grain growth (AGG). When MgO doping concentration was 900 ppm, SiO₂ doping concentration were 300, 600, 900 ppm with 3 points for doping, samples of alumina powder B were sintering in 1900℃. Greater grain, same crystal orientation of alumina material was obtained. And its optical transmission was 5 times higher than polycrystal transparent alumina.In conclusion, greater grain, same crystal orientation and high optical transmission of alumina were obtained with addition of MgO-SiO₂. At the same time, a thorough explanation and discussion on the alumina abnormal grain growth was also given based on the materials analysis technology. Therefore, this research is valuable to the low cost preparation of alumina ceramics.