화학공학소재연구정보센터
Journal of Materials Science, Vol.38, No.18, 3831-3843, 2003
Ultrafine microsphere particles of zirconium titanate produced by homogeneous dielectric-tuning coprecipitation
Zirconium titanates are widely used in electrical ( common microwave dielectrics) and optical devices as well as in bifunctional catalysis and structural ceramics. In this paper, ultrafine amorphous solid microsphere precursor particles of zirconium titanate (ZrxTi1-xO2) with possibly tailored intraparticle nanostructure (i.e., nanosized pores) were synthesized by a "dielectric-tuning" solution coprecipitation method, in which inorganic salts were dissolved in a simple water-alcohol mixture and homogeneous nucleation and growth of particles were then induced by heating at temperatures below 100degreesC. Near-monodispersed particles were obtained. Particle sizes (nanometers to a few micrometers in diameter) were controlled by adjusting the process parameters such as salt concentration, alcohol-to-water volume ratio, temperature, and heating time. Nanosphere particles were produced with a rapid microwave heating nucleation-control scheme. Transmission electron microscopic analysis of each individual microsphere indicates that uniform nanostructures ( a few nanometers in pore size) as well as compositional homogeneity ( in terms of the Zr/Ti ratio) have been obtained inside each amorphous microsphere. In situ high-temperature X-ray diffraction data show that no phase segregation was observed in as-preprared microspheres and the transition from amorphous to the single-crystalline ZrTiO4 phase occurred around 650degreesC for a composition of Zr/Ti = 1. Interestingly, thermal analysis (DTA/TGA) data indicate that the solution synthesis condition seems to affect the crystallization activation energy and onset temperature, which varies from 530 to 680degreesC. (C) 2003 Kluwer Academic Publishers.