Effect of sintering temperature on microstructure and mechanical properties of β-Sialon ceramics with Y₂O₃‒Al₂O₃‒ZrO₂ composite sintering additive

The β-Sialon ceramics were fabricated by spark plasma sintering, using 10% Y₂O₃‒Al₂O₃‒ZrO₂ composites (mass fraction) as sintering additives. The effects of sintering temperature on the phase composition, microstructure, mechanical and tribological properties of the ceramics were investigated. The results show that the relative density, Vickers hardness, and fracture toughness of the β-Sialon ceramics firstly increase and then decrease from 1300 ℃ to 1800 ℃, reaching the maximum at 1700 ℃. The ZrN impurity phases are observed in the samples sintered at 1500 ℃, 1600 ℃, and 1800 ℃ with the relatively low relative density; only the β-Sialon phases are observed in the samples sintered at 1700 ℃ with the uniform grain distribution and few small pores. The best overall performance is obtained at 1700 ℃ with the relative density of 98%, Vickers hardness of 15.15 GPa, fracture toughness of 5.55 MPa·m^1/2, and wear rate of 3.75×10^–6 mm³·(Nm)^‒1.