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.
Synthesis of porous MgAl2O4 fibers by solid-state reaction
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 increa-ses,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.
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