EFFECTS OF GEL PRE-CARBONIZATION ON Ca_(0.4)Sr(0.6)Bi_4Ti_4O_(15) NANOCRYSTALLINE POWDER

Calcium strontium bismuth titanium (Ca0.4Sr0.6Bi4Ti4O15) 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 Ca0.4Sr0.6Bi4Ti4O15 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 100 nm;however, the particle size without gel pre-carbonization was in the range of 100 nm-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.