Effects of Spray Pyrolysis Conditions on Character of Yttria Partially Stabilized Zirconia Powders

Abstract

Fine yttria-partially-stabilized zirconia powders were prepared by the spray pyrolysis method from a water: alcohol solution of ZrO(NO3)2⋅2H2O and YCl3⋅6H2O corresponding to 2mol% Y2O3. Effects of flow rates of atomizing air and solution, concentration of solution and reaction furnace temperature on the powder properties such as particle size, specific surface area, crystallite size and crystalline phase of as-synthesized powders were examined. It was observed that the as-synthesized powders are tetragonal phase containing 2±0.3 mol% Y2O3. The particle size was 0.2-5μm and a particle was agglomerates of fine crystallite of 165-210A in size. The powder consisted of hollow spherical or lath like particles and the specific surface area was 3-11m2/g. The size of agglomerate decreased with increasing atomizing air flow rate, of which the pyrolysis was independent. With increasing rate of solution, the size of agglomerate increased, but this size was not sensitive to the increase in the concentration of solution. In both cases, the pyrolysis of the salts was incomplete. A similar phenomenon was observed in the powder preparation at low temperatures.