Formation of Ln-Si-Al-O-N glasses and their properties

The preparation details of bulk glasses in the Ln-Si-Al-O-N systems (Ln = Y, Ce, Nd, Sm, Eu, Dy, Ho and Er) containing 17 equivalent % nitrogen are reported. The properties of these oxynitride glasses are examined in detail. Changes observed in density, molar volume, hardness, thermal expansion and glass transition temperature are presented and are found to vary linearly with the cationic field strength or ionic radius of the rare earth modifier. The implications for changes in glass structure caused by the substitution of one rare earth cation for another are discussed in relation to the property changes observed.