Influence of precursor preparation via ammonolysis route on alumina-zirconia nanostructure

Al2O3-ZrO2 composite precursor was synthesized by introducing ammonia into a liquid mixture of ZrO2 sol and Al (NO3)(3) aqueous solution. Precipitatio n of bayerite suggested a degradation in the dispersion of ZrO2 nanoparticl es in the Al2O3 matrix during heat treatment. In order to avoid the formati on of bayerite, it was preferred to produce a precipitation with a diluted NH3 water solution with NH3 + N-2 gas by controlling the hydration temperat ure and the NB3-adding methods. After suitable calcination and hot pressing , we successfully synthesized a uniform Al2O3-ZrO2 microstructure in which tetragonal zirconia particles of 30 nm were finely dispersed within the alu mina grains.