In situ synthesis and properties of self-reinforced $$\hbox {Si}_{3} \hbox {N}_{4}\textendash \hbox {SiO}_{2}\textendash \hbox {Al}_{2} \hbox {O}_{3}\textendash \hbox {Y}_{2}\hbox {O}_{3} \ (\hbox {La}_{2}\hbox {O}_{3}$$ Si 3

Abstract

In-situ-grown β-Si 3 N 4-reinforced SiO 2-Al 2 O 3-Y 2 O 3 (La 2 O 3) self-reinforced glass-ceramic composites were obtained without any β-Si 3 N 4 seed crystal. These composites with different compositions were prepared in a nitrogen atmosphere for comparison of phase transformation and mechanical properties. The results showed that SiO 2-Al 2 O 3-Y 2 O 3 (La 2 O 3) glass can effectively promote αto β-Si 3 N 4 phase transformation. The crystallized Y 2 Si 2 O 7-La 4.67 Si 3 O 13 phases with a high melting point significantly benefited the high-temperature mechanical properties of the composites. The Si 3 N 4-SiO 2-Al 2 O 3-Y 2 O 3 (La 2 O 3) glass-ceramic composites exhibit excellent mechanical properties compared with unreinforced glass-ceramic matrix, which is undoubtedly attributed to the elongated β-Si 3 N 4 grains. These glass-ceramic Si 3 N 4 composites with excellent comprehensive properties might be a promising material for high-temperature applications.