Abstract In this work, Al2O3-ZrO2 (Y2O3) nanoceramics were prepared via pressureless sintering of powders with different degrees of crystallinity. It was demonstrated that, the crystallization of amorphous phase in starting powders highly enhanced the densification during sintering. When the crystal content was 25 vol%, the powders exhibited better sinterability than other powders, and they could be sintered into bulk nanoceramics with relative densities higher than 98% at 1400 °C and 1500 °C. The superior sinterability of C25 powders was due to the crystallization of amorphous phase promoted by the as-existed nanocrystalline powders as nucleation seeds. The obtained nanoceramic exhibited homogenously distributed ZrO2 and Al2O3 particles with grain size of about 450 nm, and displayed excellent mechanical property with Vickers hardness of 15.3 GPa, fracture toughness of 5.2 MPa m1/2, and flexure strength of 1190 MPa. This work may provide new guidance for optimization in preparing bulk nanoceramics by managing the crystallinity of starting powders.

中文翻译：

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通过无压烧结不同结晶度的粉末制备纳米颗粒Al 2 O 3 -ZrO 2 (Y 2 O 3 )陶瓷

摘要 本工作通过对不同结晶度的粉末进行无压烧结制备了Al2O3-ZrO2(Y2O3)纳米陶瓷。结果表明，起始粉末中非晶相的结晶极大地增强了烧结过程中的致密化。当晶体含量为25 vol%时，粉末表现出比其他粉末更好的烧结性，在1400℃和1500℃下可以烧结成相对密度高于98%的块状纳米陶瓷。C25 粉末优异的可烧结性是由于纳米晶粉末作为成核种子促进了非晶相的结晶。所得纳米陶瓷呈现均匀分布的 ZrO2 和 Al2O3 颗粒，晶粒尺寸约为 450 nm，并表现出优异的力学性能，维氏硬度为 15.3 GPa，断裂韧性为 5.2 MPa m1/2，弯曲强度为 1190 MPa。这项工作可能为通过控制起始粉末的结晶度来优化制备块状纳米陶瓷提供新的指导。