液相沉淀法制备云母玻璃陶瓷粉体的晶化行为

Crystallization of Mica Glass-ceramic Powder Prepared by Liquid-phase Precipitation Method

为了获得致密的云母玻璃陶瓷烧结体，采用液相沉淀法制备出分散性好的复合氧化物前驱粉体，粉体经两步法晶化热处理后得到主晶相为氟金云母（NaMg3 AlSiO3O10F2）的可加工云母玻璃陶瓷粉体．采用DTA／TGA，FT-IR，XRD，TEM分析了粉体的晶化过程．结果表明，液相沉淀制备的前驱粉体为非晶态，颗粒呈近球形，颗粒尺寸大约在10～20nm之间，大小比较均匀，有少量团聚现象．在经过晶化热处理后的粉体形貌主要呈片层状；氟金云母相结构在600℃左右开始析出，在650℃时形核速率最大，同时伴随有少量的镁橄榄石（Mg2SiO4）和霞石（NaAlSiO4）析出；粉体经两步法晶化热处理后粉体晶化度达到45％左右．

In order to get the compact mica glass-ceramic sintered body, the powder precursor of complex oxide was prepared by liquid -phase precipitation method, the powder was treated by the twostep crystallization heat treatment to get machinable mica glass- ceramic powder containing fluorophlogopite（NaMg3 A1SiO30x0Fz ） as the main crystalline phase. The crystallization procedure of the powder was investigated using DTA/TGA, FT- IR, XRD and TEM. The results show that the morphology of the prepared powder precursor particle is nearly spherical, the size of the particle is in the range of 10 -20 nm,and the particle is uniform and with a little agglomeration. The morphology of the powder treated by the crystallization heat treatment is mainly lamellar. The fluorophlogopite is tobe crystallized at about 600 ℃, and with the largest nucleation rate at 650℃. Meanwhile a small quantity of nepheline（NaAlSiO4） and forsterite（Mg2SiO4） are also crystallized out at 650 ℃. The crystallization degree of the powder, after heat treatment, reached about 45 %.