Spark Plasma Sintering of Nano Silicon Carbide Reinforced Alumina Ceramic Composites

Abstract

At this point, it is reported that the amount, size, morphology and distribution of SiC phase added into the alumina matrix has a great effect on the mechanical properties of Al 2 O 3 [11]. Razavi et al. [10] produced the Al 2 O 3 -SiC composite ceramics by using spark plasma sintering (SPS) method at temperatures of 1600 °C for 10 min holding time and they measured the hardness and fracture toughness values of the monolithic Al 2 O 3 as 1387 Hv and 250.4 MPa, respectively. Researchers showed that hardness of the composite containing 20 wt. % Abstract Although Al 2 O 3 has been commercially preferred material, it cannot be used in applications subject to variable and sudden loads due to its low fracture toughness. In this study, as the primary purpose, nano-SiC particles were used as reinforcement phase to improve the fracture toughness of the Al 2 O 3 ceramic. Ultrasonic dispersion was used to ensure good dispersion of the nano reinforcement phase in the matrix. Production was carried out by spark plasma sintering method at temperatures of 1325 °C for 5 min under 40 MPa pressure and vacuum atmosphere. Densification behavior, density, microstructure, phase analysis, hardness and fracture toughness of the sintered Al 2 O 3 /nano-SiC composites were investigated. The highest hardness and fracture toughness of 22.83 GPa and 6.09 MPa·m 1/2 were achieved, respectively.