采用包裹工艺和热压工艺制备了Al2O3/Ni金属陶瓷。在1450℃热压Ni包裹Al2O3复合粉体得到相对密度>98％的金属陶瓷,当温度>1400℃时,随着Ni含量的增加致密度下降.Ni颗粒位于三角晶界,随着含量的增加,断裂方式由沿品转为穿晶断裂;在Al2O3基体中引入Ni颗粒能够降低晶粒尺寸,提高强度和韧性.与单相Al2O3的力学性能相比,综合力学性能较好的NA4金属陶瓷的抗弯强度和断裂韧性分别提高了19％和35％,分析了金属陶瓷的增强增韧机制.
Ni-coated Al2O3 powders with different Ni content were prepared by the coating technique. The powders were sintered by hot-pressing, and Al2O3/Ni cermet obtained. Results show that
the densification is enhanced with the increase of temperature, and when temperature is more than 1400℃, the densification is decreased with the increase of Ni content. Ni particles introduced
in Al2O3 ceramic matrix can reduce grain sizes, enhance strength and toughness. Compared with single phase Al2O3 material,
Al2O3/4vol% Ni cermet has flexural strength of 19% and fracture toughness of 35% enhanced. SEM photos of fracture surface show that the fracture model of the cermet changes from intergranular fracture
to transgranular fracture with the increase of Ni content.
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