The fracture toughness of spark plasma sintered nano-nano t'-YSZ- Al2O3 in situ composite ceramics

Nano-nano t'-YSZ-Al 2 O 3 composites were synthesized in situ using sol-spray pyrolysis process. The composite powders were sintered into dense ceramics by spark plasma sintering at 1300 °C. The toughness of the composite ceramics was studied, and the microstructure was characterized in detail using X-ray diffraction spectroscope (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM). Microstructural analysis revealed that α-Al 2 O 3 , with a grain size of approximately 100 nm, was distributed along the grain boundaries of YSZ. Notably, the toughness of the YSZ-Al 2 O 3 composite ceramics with 10 wt% Al 2 O 3 addition (85±5 J/m 2 ) was nearly twice that of single-phase YSZ (43±3 J/m 2 ). It is suggested that the nano-toughening can be comparable to ferroelastic toughening. Materials with enhanced toughness can significantly improve the thermal cycling life of coatings, indicating that nano/nano YSZ-Al 2 O 3 composites hold considerable potential for practical applications.