Synthesis and characterization of sol-gel derived ZrO2 doped Al2O3 nanopowder

Al2O3-ZrO2 composite gel precursor powder containing 5-15 mol% ZrO2 was prepared by a wet chemical route. The washed gel containing pseudoboehmite and amorphous zirconia was characterised by DTA/TG, XRD and IR spectroscopy. DTA/TG indicated three-stage decomposition for pseudoboehmite and single stage decomposition for amorphous zirconia. In the calcined powder phase, evolution of Al2O3 followed the sequence pseudoboehmite to bayerite to boehmite to gamma-Al2O3 to theta-Al2O3 to alpha-Al2O3, while that of ZrO2 followed amorphous ZrO2 to t-ZrO2 to (t + m)ZrO2. FTIR studies revealed that the number of M-OH and M-O bond increased with increasing mol% of ZrO2 due to a change in the cationic charge of the composite powder. TEM photography of calcined powder showed both dispersed nano-size spherical particle as well as agglomerated particles. EPMA confirmed the near uniform distribution of zirconia particles in the alumina matrix. 27 refs.