COMBUSTION SYNTHESIS OF YTTRIA

Fine-particle, sinter-active yttria has been prepared by combustion of a redox compound, Y(N2H3COO)(3) . 3H(2)O and mixtures of Y(N2H3COO)(3 ) . 3H(2)O-NH4NO3 or NH4ClO4 as well as yttrium nitrate and hydrazine- based fuels. The fine-particle nature of the combustion-derived yttria has been investigated using powder density, particle size and BET sur face area measurements. The uniaxially, cold-pressed fine-particle ytt ria when sintered at 1450-1500 degrees C achieved 98% theoretical dens ity and showed a fine-grain (1-2 mu m) microstructure.