Sintering kinetics of nanocrystalline Ce0.9Zr0.1O2 prepared by gel combustion method

Abstract

The sintering process of nanometric Ce0.9Zr0.1O2 mixed oxides prepared by the amino acid–nitrate gel combustion method was analyzed by dilatometry using the constant heating rate (CHR) and stepwise isothermal dilatometry (SID) methods. The morphology of the mixed oxides was studied by scanning and transmission electron microscopies. The evolution of crystallite size with temperature was analyzed by time-resolved X-ray powder diffraction with synchrotron radiation. The sintering behavior resulted dependent on the morphology of the powders. Samples with nanometric crystallite size start to sinter even 500 K before than micrometric sample. We concluded that sintering process of nanometric Ce0.9Zr0.1O2 is controlled by grain-boundary diffusion for temperatures below 1373–1573 K, depending on the morphology of the sample. At high temperature, the grain-boundary and lattice diffusion become parallel controlling mechanism for sintering.