凝胶预碳化处理对Ca0.4Sr0.6Bi4Ti4O15纳米晶粉体的影响

用凝胶预碳化处理工艺的溶胶-凝胶法制备了晶粒粒径小且分散性能较好的钙锶铋钛(Ca0.4Sr0.6Bi4Ti4O15)纳米晶粉体.借助差热-热重分析仪、X射线衍射仪和扫描电镜等分别确定凝胶的预碳化处理温度,研究了预碳化处理工艺对粉体的物相结构、粉体的微观形貌以及分散性能的影响,并分析讨论了预碳化机理.结果表明:在300℃对前驱体凝胶进行预碳化处理增强了粉体的分散性,降低粉体的粒度,提高粉体的均匀性.凝胶预碳化处理工艺并未对粉体的物相结构造成影响.经过预碳化处理制备的粉体的颗粒尺寸集中在100nm左右;未经预碳化处理的粉体的颗粒尺寸为100nm～1 μm.凝胶预碳化处理后,高吸附活性的有机碳包覆在前驱体的表面是有效减少粉体团聚的原因.

EFFECTS OF GEL PRE-CARBONIZATION ON Ca0.4Sr0.6Bi4Ti4O15 NANOCRYSTALLINE POWDER

Calcium strontium bismuth titanium(Ca0.4Sr0.6BirTi4O15)nanocrystalline powder with small particle size and good dispersion was prepared via the gel pre-carbonization sol-gel method.The temperature for gel pre-carbonization was determined by differential scanning calorimetry-thermal gravimetric analysis.The effects of pre-carbonization of gel on the properties such as the phase structure,microstructure and dispersion of the Ca0.4Sr0.6BirTi4O15 nanocrystalline powder were studied by X-ray diffraction and scanning electron microscope,respectively,and the pre-carbonization mechanism was also analyzed.Experimental results show that,after gel pre-carbonization at 300℃,the dispersion of the Ca0.4Sr0.6Bi4Ti4O15 nanocrystalline powder improved,the particle size decreased,and the homogeneity of the powder improved.The phase structure was not influenced.The particle size with gel pre-carbonization was about 100nm;however,the particle size without gel pre-earbonization was inthe range of 100nm-1 μm.The mechanism is that,after the pre-carbonizing treatment,the precursor powder is modified and coated with carbon powder,which reduces grain agglomeration effectively.