| abstract |
Oxynitride glass whose composition is represented by Al-Si-O-N or M-Al-Si-O-N (where M denotes Ca, Mg, or rare earth element), wherein the content of O and N as non-metallic components is in the range of 0 eq %<N<=30 eq %, with O+N=100 eq %, the content of M, Al, and Si as metallic components is in the range of 20 eq %<=Al<=30 eq % and 70 eq %<=Si<=80 eq %, respectively, with Al+Si=100 eq % (if M does not exist) and the content of M, Al, and Si as metallic components is within the hatched area in the composition diagrams shown in FIGS. 1 to 3, if M is Ca, Mg, or rare earth metal, or within the hatched area in the composition diagrams shown in FIGS. 4 to 8, if the content of N is in the range of 5 eq %<=N<=25 eq %. This glass is superior in specific rigidity and fabricability. It contains nitrogen in a controlled amount so that it has improved specific rigidity without its specific gravity increasing. |