摘要
以硝酸镁和硝酸铝为主要原料,NH3·H2O为沉淀剂,用均相混合物共沉淀法制得镁铝混合均匀的溶胶,再用真空冷冻干燥(VFD)方法在-50℃,13.3Pa的真空度下制得MgAl2O4的前驱体粉体。用TG-DSC、XRD、TEM及Autosorb-1-M等仪器研究了热处理温度及反应体系的pH值对镁铝均匀混合纳米粉体材料的物相转变、显微形貌、表面性能等的影响。研究表明:控制溶液的pH值在9.0附近,采用共沉淀-真空冷冻干燥方法,可制得粒径小、比表面积大的MgO-Al2O3二元混合纳米粉体,且其起始尖晶石化温度在600℃,经过1000℃2h处理后,已全部转变成粒径为50nm左右的纳米尖晶石,比传统制备镁铝尖晶石的温度低500～600℃。
The homogeneous magnesia alumina sol was firstly prepared using magnesium nitrate and aluminum nitrate as main starting materials, and NH3 · H2O as precipitation agent with the technique of homogeneous compost coprecipitation method. And then, the precursor powder of alumina-magnesia spinel was obtained by vacuum freezing drying the above sol at -50°C in vacuum room (vacuity: 13.3 Pa). The influences of heat treatment temperature and pH value in the precipitation system on the surface properties, microstructure morphology and phase transform were investigated by means of thermogravimetry differential scanning calorimeter (TG-DSC), X-ray diffractmeter (XRD) transmission electron microscope (TEM) and apparatus of physical adsorption (Autosorb-1-MP). The results show that controlling appropriate pH value (about 9) of the solution, and employing the coprecipitation with vacuum freezing drying, can gain the composite nano-size powder of binary magnesia alumina with small particle size and high specific surface area, which has low initial spinellization temperature about 600°C, and the completely spinellization temperature is 1000°C with 50 nm powder particle size, lower than the temperature of traditional methods 500-600°C.
出处
《耐火材料》
EI
CAS
北大核心
2005年第3期168-171,共4页
Refractories
基金
湖北省科技攻关计划重点项目(2001AA101B07)
武汉市重大科技攻关计划项目(20011007088)。
