In order to optimize the phase composition and grain size of alumina fibers, 0-3 wt% SiO₂ were induced to prepare alumina fibers using sol-gel method with the reaction of aluminium powder, formic acid, acetic acid, nitric acid and SiO₂ sol. Effects of low SiO₂ content on the phase transition and microstructure of alumina fibers were investigated. X-ray diffraction analysis and differential scanning calorimetry results showed that the addition of silica delayed the formation of α-Al₂O₃, and the phase transformation path of alumina was changed from amorphous alumina → γ-Al₂O₃ → α-Al₂O₃ to amorphous alumina → γ-Al₂O₃ → θ-Al₂O₃ → α-Al₂O₃. Moreover, scanning electron microscopy and transmission electron microscopy results confirmed that the addition of SiO₂ reduced the grain size and was beneficial for the dense structure. Fine-grained dense alumina fibers composed of α-Al₂O₃ phase and transitional alumina phase were obtained by adding 1 wt% and 3 wt% silica after sintering at 1200°C for 1 h.

为了优化氧化铝纤维的相组成和晶粒尺寸，采用溶胶-凝胶法诱导0-3 wt% SiO ₂制备氧化铝纤维，铝粉、甲酸、乙酸、硝酸和SiO ₂反应。溶胶。研究了低SiO ₂含量对氧化铝纤维相变和微观结构的影响。X射线衍射分析和差示扫描量热法结果表明，二氧化硅的加入延缓了α-Al ₂ O ₃的形成，氧化铝的相变路径由无定形氧化铝→γ-Al ₂ O ₃ →α-Al ₂ O ₃到无定形氧化铝 → γ-Al ₂ O ₃ → θ-Al ₂ O ₃ → α-Al ₂ O ₃。此外，扫描电子显微镜和透射电子显微镜结果证实，SiO ₂的添加降低了晶粒尺寸，有利于致密结构。在1200℃烧结1 h后，分别加入1 wt%和3 wt%的二氧化硅，得到由α-Al ₂ O ₃相和过渡氧化铝相组成的细晶致密氧化铝纤维。