Bending strength, hardness, thermal expansion coefficient, fracture toughness and weight gain (1300°C, 100h in air) of the β-sialon and β-sialon-50wt% SiC composite hot pressed at 1850°C and annealed at 1900° and 2000°C were measured.
(1) The strength and hardness of β-sialon and β-sialon-50wt% SiC composite decrease with increase in annealing temperature.
(2) Fracture toughness of β-sialon and β-sialon-50wt% SiC composite is about 3.0MNm^-3/2 and 4.3MNm^-3/2 respectively. They are independent of annealing temperature.
(3) Thermal expansion coefficient of β-sialon as hot-pressed and annealed at 1900° and 2000°C is 2.4-2.5×10^-6°C^-1 That of β-sialon-50wt% SiC composite as hot-pressed and annealed at 1900°C is 3.0×10^-6°C^-1 and annealed at 2000°C is 3.5×10^-6°C^-1.
(4) Weight gain of both β-sialon and β-sialon-50wt% SiC oxidized at 1300°C for 100h is nearly zero.