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
N
4
–
SiO
2
–
Al
2
O
3
–
Y
2
O
3
(
La
2
O
3
) glass–ceramic composites