透明MgAl_2O_4晶须的制备与表征

Synthesis and Characterization of Transparent MgAl_2O_4 Whiskers

本文采用MgO粉和金属Al粉为原料,在氮气气氛下制备MgAl2O4晶须,研究了TiO2、SiO2或Cr2O3等供氧添加剂和制备条件对晶须合成率的影响并分析了晶须的物相组成和结构。结果表明:最佳MgO/Al=2/3;添加SiO2或Cr2O3不利于晶须合成;添加TiO2对合成晶须有促进作用,最佳TiO2加入量为40%;采用氧化铝坩埚比采用釉面陶瓷坩埚好,最佳保温时间为6h。合成的晶须为MgAl2O4,空间群Fd3M,晶格常数a=b=c=0.8083nm,MgO28.3%,Al2O371.7%;晶须呈透明柱状,最大长度为20～30mm,长径比20～400。

Transparent MgAl2O4 whiskers were prepared in a nitrogen atmosphere using MgO powders and metal Al powders as the main raw materials. The effects of the additives of TiO2, SiO2 or Cr2O3, and the preparation conditions on synthesis rates of the MgAl2O4 whiskers were investigated, the phase composition and structure of MgAl2O4 whiskers were also studied in this paper. The results show that the optimum conditions for the growth of transparent MgAl2O4 whiskers are MgO/Al = 2/3, with additive of TiO2 （40%） , using alumina crucible, and with a heating time of 6 h. The space group of the as-obtained MgAl2O4 whiskers, with a composition of MgO 28.3% , Al2O3 71.7 % , is Fd3M, and their lattice constants are a = b = c = 0. 8083 nm. The maximum lengths of the transparent MgAl2O4 whiskers are 20 - 30 mm, and the length-to-diameter ratios are 20 -400.