镁铝尖晶石粉体的制备与表征

Preparation and characterization of magnesium aluminate spinel powder

以Mg、Al、TiO_2和B_2O_3粉体为原料,采用自蔓延高温合成法合成了MgAl_2O_4和TiB_2复合粉体,用稀硝酸除去产物中的TiB2及残余反应物后,获得了较高纯度的MgAl_2O_4。然后用MgO部分取代Mg研究了不同Mg源对合成产物的影响,用XRD和SEM检测了两组反应获得的MgAl_2O_4粉体,用激光粒度测试仪分析了产物的粒径大小及分布,用红外光谱仪测试了粉体性能较佳的反应酸洗产物的红外透光率。结果表明,以单一Mg粉为Mg源时,MgAl_2O_4的相对含量为85.96%,且颗粒较小,平均粒径为5.36μm,粒径分布较集中,0.1~10μm的颗粒占80.68%;以(Mg+MgO)为Mg源时,MgAl_2O_4的相对含量为71.55%,且颗粒较大,平均粒径为11.18μm,粒径分布较分散,0.1~10μm的颗粒占54.96%;综合考虑,以Mg为镁源获得的MgAl_2O_4粉体性能好,经红外光谱分析,可得,MgAl_2O_4透过率高,透过波段范围宽,在1 100~2 978cm^(-1)之间的红外透过率达到50%以上,高透光率的镁铝尖晶石具有低的辐射率,可应用于红外隐身材料。

The composite powders of MgAl_2O_4 and TiB2 were prepared by self-propagating high-temperature synthesis method with Mg powder,Al powder,TiO_2 powder and B_2O_3 powder as raw materials.Then relatively high purity magnesium aluminate spinel powders were obtained after ultrasonic pickling by using 20wt% nitric acid to remove TiB_2 and residual reactants in the product.The effect of different magnesium sources on the product was studied by MgO partially replacing Mg;the productivity and the particle size of the two reaction system were analyzed in contrast by XRD and SEM.And also the purity of MgAl_2O_4 after acid pickling was studied.The results show that MgAl_2O_4 in the products account for 85.96% with Mg as magnesium source,the particles are fine with average particle size 5.36μm and 80.68%of the particles range from 0.1to 10μm;MgAl_2O_4in the products account for 71.55% with Mg and MgO as magnesium source,the particles are relatively large with average particle size 11.18μm and the particle size distribution is relatively wide as 54.96%are in the range of 0.1-10μm.Reaction products MgAl_2O_4 without MgO addition have high transimittance and wide wavelength range as the transmittance of MgAl_2O_4 reaches more than 50% between 1 100 and 2 978cm-1.MgAl_2O_4 of high transimittance has low radiation,so it can be used as infrared stealthy materials.