GLASS-FORMING REGIONS AND THERMAL-EXPANSION OF SOME LN-SI-AL-O-N GLASSES (LN=LA,ND)

The, are earth sialon glass forming regions in La-Si-Al-O-N and Nd-Si- Al-O-N systems have been defined and the thermal expansion coefficient s of these glasses measured. It was found that the glass forming regio ns in these systems are larger than in other M-Si-Al-O-N systems (M = not a rare earth) and the maximum solubility of nitrogen in these glas ses is in excess of 45 eq.-%. The thermal expansion coefficients of th ese glasses increase when Al is replaced by Si or Ln (Ln=La, Nd), but decrease with increasing nitrogen content. (C) 1996 The Institute of M aterials.