The Spark Plasma Sintering of Silicon Carbide Ceramics Using Alumina

SiC ceramics were fabricated by spark plasma sintering technique with the use of $Al_2O_3$ additive. The sintering process was carried out at three different temperatures in the range of 1700-1800C applying two different pressures 40 and 80 MPa under vacuum atmosphere. The effect of additive, different temperatures and pressures on densification behaviour, density, Vickers hardness, fracture toughness, and microstructure were examined. The hardness and fracture toughness of the samples were evaluated by the Vickers indentation technique. Microstructure of spark plasma sintered SiC samples were characterized by using scanning electron microscopy technique. The highest value of fracture toughness $5.9 ± 0.2$ MPa $m^{1/2}$ was achieved with the addition of 5 vol.% $Al_2O_3$.