Two series of Al2O3 -ZrO2 powders with various contents of ZrO2 were synthesized by sol-gel (chemical polymerization) and coprecipitation methods. The effect of ZrO2 content and preparation method on the structure and texture of the resultant powders were determined. The samples were characterized by nitrogen sorption, thermal gravimetric analysis, X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy. The sol-gel method yields more homogeneous powder and retards the aggregation of particles. It produces powders with a larger surface area, a smaller pore size, and a narrower pore size distribution than the coprecipitated one. The X-ray diffraction results show that the powders are amorphous at the calcination temperature below 700 degrees C for both methods. Incorporation of zirconia into alumina greatly affects the surface properties of the powders upon heating, exerting a protective effect against sintering, and inhibiting both the crystallization of the gamma-Al2O3 phase and the gamma- to alpha-phase transformation. Zirconia is dispersed in alumina matrix and does not form a new structure.
