Abstract: The gas phase method is the main preparation method of MgAl₂O₄ fibers,but it has problems such as high reaction temperatures,high cost,and low yield.Porous MgAl₂O₄ fibers were prepared using basic magnesium sulfate whiskers as templates,mixing with alumina sol or α-Al₂O₃ micropowder through the solid-state reaction.The effects of the heat treatment temperature (1 000,1 100 and 1 300 ℃),holding time (3 and 10 h),and alumina source (alumina sol and α-Al₂O₃) on the synthesis of the porous MgAl₂O₄ fibers were studied.The results show that:(1)compared with the fiber using α-Al₂O₃ as the alumina source,the one using alumina sol generates more MgAl₂O₄;(2)as the heat treatment temperature increases,Al₂O₃ tends to react completely with MgO,thus continuously increasing the forming amount of MgAl₂O₄,and the synthesized porous MgAl₂O₄ fibers have small and uniform nanopores;(3)the optimal synthesis process is using alumina sol as the alumina source and firing at 1 300 ℃ for 3 h.

Key words: basic magnesium sulfate whiskers, alumina sol, MgAl₂O₄, porous fibers, solid-state reaction method

摘要： MgAl₂O₄纤维的主要制备方法为气相法,但该方法存在反应温度高、制备成本高以及产率低等问题。将碱式硫酸镁晶须作为模板,分别与铝溶胶或α-Al₂O₃微粉混合,通过固相反应制备了MgAl₂O₄多孔纤维,研究了热处理温度(1 000、1 100和1 300 ℃)和保温时间(3、10 h)以及铝源(铝溶胶和α-Al₂O₃微粉)对MgAl₂O₄多孔纤维合成的影响。结果表明:1)与α-Al₂O₃微粉相比,以铝溶胶为铝源时,纤维中MgAl₂O₄生成量更高;2)随着热处理温度的升高,Al₂O₃与MgO逐渐反应完全,MgAl₂O₄的生成量不断增加,MgAl₂O₄多孔纤维上有小而均匀的纳米孔;3)最佳制备工艺是以铝溶胶为铝源,在1 300 ℃保温3 h。

关键词: 碱式硫酸镁晶须, 铝溶胶, MgAl₂O₄, 多孔纤维, 固相反应法