Abstract:
With SiC powder and silicon powder as raw materials, in-situ synthesized Cr
2O
3 as catalyst, Si
3N
4/SiC refractory was prepared by catalytic nitridation. The effects of catalyst addition amount and nitridation temperature on the phase composition, micromorphology, physical properties and mechanical properties of the refractory were investigated. The results show that when the nitridation temperature was 1 673 K and the Cr
2O
3 content (mass ratio of Cr
2O
3 to silicon powder) reached 3wt%, the silicon powder was completely nitrided; the refractory was composed of grain-like SiC, whisker-like α-Si
3N
4 and β-Si
3N
4. With increasing content of Cr
2O
3, the amount and length of Si
3N
4 whisky increased; the refractory became densification. With the rise of nitridation temperature, the flexural strength and compressive strength of the refractory increased. When the nitridation temperature was 1 673 K and the Cr
2O
3 content was 3wt%, the flexural strength and compressive strength reached the largest values of 34 MPa and 132 MPa, respectively.