In situ synthesis mechanism of 15R–SiAlON reinforced Al ₂ O ₃ refractories by Fe–Si liquid phase sintering

Abstract

Abstract 15R–SiAl ON bonded Al 2 O 3 refractories were successfully synthesized using ferrosilicon nitride and alumina by liquid phase sintering. The phase composition and morphology were analyzed by means of X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results show that 15R–SiAl ON reinforcement can be in situ obtained in the specimens with 5 wt% ferrosilicon nitride at 1500°C to 1700°C in flowing N 2 of 0.1 MP a. The morphology of 15R–SiAl ON is strongly dependent on the morphology of intermediate Al ON phases formed at different temperatures. Fe–Si alloys from ferrosilicon nitride form liquid phase and accelerate the formation of 15R‐SiAl ON , in which process the wettability of Fe–Si alloys is improved by the increase in Si content, carbon coating on particle, solution process and reactions. The 15R–SiAl ON reinforced Al 2 O 3 refractory materials possess high cold crushing strength of 138‐171 MP a.