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用真空热压烧结工艺制备了Al_2O_3–ZrO_2(3Y)/Co–Ni–BN金属陶瓷。用扫描电子显微镜及能谱分析了样品显微组织及断裂形态,研究了金属相Ni–Co和陶瓷增强相h-BN的含量对样品力学性能的影响以及抗热震性能。结果表明:在烧结温度为1 500℃、压力为30 MPa、保温30 min条件下,当Ni–Co–BN含量为12%(质量分数)时,样品的最佳抗弯强度、断裂韧性、Vickers硬度分别为1 423 MPa、14.7 MPa·m~(1/2)、13.4 GPa。样品的临界热震温差为500℃,其热震断裂因子和损伤因子分别为R′=12 981.8 J·(m~2·s)和R″″=145μm;断裂功为557 J/m~2。
Al 2 O 3 -ZrO 2 (3Y) / Co-Ni-BN cermets were prepared by vacuum hot pressing. The microstructure and fracture morphology of the samples were analyzed by scanning electron microscopy and energy dispersive spectroscopy. The effects of Ni-Co phase and h-BN phase on the mechanical properties and thermal shock resistance of the samples were investigated. The results show that the optimum bending strength, fracture toughness, Vickers hardness and fracture toughness of Ni-Co-BN samples with Ni-Co-BN content of 12wt% at a sintering temperature of 1500 ℃ and a pressure of 30 MPa for 30 min Hardness of 1 423 MPa, 14.7 MPa · m ~ (1/2), 13.4 GPa respectively. The critical thermal shock temperature difference of the sample is 500 ℃, and the thermal shock and damage factors are R ’= 12 981.8 J · (m ~ 2 · s) and R “” = 145μm respectively. The fracture work is 557 J / m ~ 2 .