A coprecipitated xerogel having the composition of 90 vol.% zirconia (3 mol% Y2O3) and remaining 10 vol.% alumina was crystallized under hydrothermal conditions by adopting conventional (110 degreesC for 7 days) or microwave (250 degreesC for 2 h) routes. The hydrothermal treatments of crystallization were performed in the presence of (KOH + K2CO3) (K), (CH3)(4)NOH (TMA), or (C2H5)(4)NOH (TEA) mineralizer solutions at different concentrations. The role of the two different hydrothermal routes, of the nature and the concentration of the mineralizer solution on the thermal behaviour of the resulting powders are discussed. (C) 2004 Elsevier B.V. All rights reserved.