液相沉淀法制备Al_2O_3-SiO_2-CaF_2系玻璃粉体的晶化特性

Crystallization of Al_2O_3-SiO_2-CaF_2 Glass Powder Prepared by Liquidphase Precipitation Synthesis Method

采用液相沉淀法制备了超细Al2O3-SiO2-CaF2系玻璃粉体，并对粉体进行了不同温度下的热处理，借助XRD、TEM、DSC等手段研究了初始粉体特征及晶化特性．结果表明，液相沉淀初始粉体呈典型的非晶态特征，粉体颗粒呈近球形形貌，颗粒尺寸在30-70nm范围内；温度在500-800℃范围内，粉体发生一系列析晶转变，在温度约为545℃时优先析出CaF2晶相，随温度升高，依次析出Al2SiO5、Ca2SiO4等晶相．

Ultra-fine glass powders of Al2O3-SiO2-CaF2 are prepared by the precipitation process, and the prepared powders are treated with heat treatment in different temperatures. The characteristics of the powders are studied by using XRD, TEM and DSC. The results indicate that the prepared powder belongs to amorphous compounds, and the size of the nearly spherical particle is in the range of 30 - 70 nm. As the temperature is in the range of 500 - 800 ℃, the crystal phase of CaF2 is crystallized firstly from the prepared amorphous powder at about 545℃ ; with the temperature rising, Al2SiO5、Ca2SiO4crystal phases are also separated out sequentially.