Microstructure and mechanical properties of La2Zr2O7-(Zr0.92Y0.08)O1.96 composite ceramics prepared by spark plasma sintering

Dense composite ceramics composing of pyrochlore La2Zr2O7 and metastable tetragonal (Zr0.92Y0.08)O1.96 phases were synthesized by sol-spray pyrolysis method and were densified by using spark plasma sintering at 1450 °C. The microstructure and mechanical properties of the composites were studied. Microstructure analysis showed that particle size of the La2Zr2O7 and (Zr0.92Y0.08)O1.96 phases of the composites was in the range of 0.2-1.3 μm. The results of mechanical property measurement revealed that high fracture toughness, almost twice that of single phase La2Zr2O7 has been achieved for the La2Zr2O7-(Zr0.92Y0.08)O1.96 composite ceramics with 50 mol% 4YSZ addition. The improved toughness was attributed to crack blocking of the (Zr0.92Y0.08)O1.96 crystals.