Al2O3/AlB12/AlN复相陶瓷的制备及其力学性能

以Al和B2O3为原料,采用高频感应加热方法制备出纯的Al2O3/AlB12/Al复合陶瓷粉体,然后在N2保护下1600℃热压烧结2h制备出Al2O3/AlB12/AlN复相陶瓷。采用XRD和SEM技术分别表征了Al2O3/AlB12/Al复合陶瓷粉的相和形貌以及Al2O3/AlB12/AlN复相陶瓷的相和断口形貌。采用三点弯曲法和压痕法分别测试了Al2O3/AlB12/AlN复相陶瓷的抗弯强度和断裂韧性。研究结果表明：由于室温下Al-B2O3体系的绝热温度大于1800K,因此可以采用高频感应加热方法点燃Al-B2O3体系,并制备出纯的Al2O3/AlB12/Al复合陶瓷粉体;Al2O3相和AlB12相是分别通过液-液反应机制和液-固反应机制生成;Al2O3/AlB12/AlN复相陶瓷的抗弯强度和断裂韧性分别为549.48MPa和5.96MPa·m1/2,分别比纯Al2O3陶瓷的350MPa和4MPa·m1/2高56.99%和49%,这可能是原位反应生成的细小AlN颗粒增强增韧了Al2O3基陶瓷。

Fabrication and Mechanical Properties of Al2o3/alb12/aln Composite Ceramics

Based on the raw materials of Al and B2O3, the pure Al2O/AlB12/Al composite ceramic powders were synthesized by a high frequency induction heating method. The Al2O/AlB12/Al composite ceramics were fabricated by hot pressing sintering at 1600℃ for 2h under the protection of N2. The XRD and SEM techniques were Used to characterize the phases and morphologies of the Al2O/AlB12/Al composite ceramic powders and the Al2O/AlB12/AlN composite ceramics.The bending strength and the fracture toughness of the Al2O/AlB12/AlN composite ceramics were measured by three-point bending method and indentation fracture method, respectively. The results show that the pure Al2O/AlB12/Al composite ceramic powders can be synthesized by a high frequency induction heating method because the adiabatic temperature of Al-B2O3 system is more than 1800K. The Al2O3 phase and the AlB12 phase were formed by the liquid-liquid reaction mechanism and the liquid-solid reaction mechanism, respectively. The bending strength and the fracture toughness of the Al2O/AlB12/AlN composite ceramics were 549.48MPa and 5.96MPa.m1/2,respectively,and these values are bigger 56.99%and49%than that of pure Al2O3 ceramics due to the reinforcing and toughening of Al2O3-based ceramics by in-situ formation small AlN particles.