IAM - Ceramic Materials and Technologies

Thermal, elastic and dielectric properties of rare-earth containing oxynitride glasses

  • Author:

    Lofaj, F.; Rouxel, T.; Hoffmann, M. J.

  • Source:

    SILICATES INDUSTRIELS 69 (2004), 5-6, 95–104 

  • Thermal, elastic and dielectric properties of rare-earth containing oxynitride glasses.

Abstract

Thermal expansion coefficients (alpha), glass-transition (T-g) and softening (T-L) temperatures, elastic moduli, dielectric constants (epsilon) and dielectric losses (tan delta) of bulk RE-Si-Mg-O-N glasses (RE = Sc, Y, La, Nd, Sm, Gd, Yb, and Lu) with different nitrogen contents were investigated to evaluate the compositional effects. Lanthanides modify a. of the studied oxynitride glasses with 20 and 24 eq.% N by similar to12%, T-g by 32-38degreesC, Young's modulus from 130 to 150 GPa (similar to13%), epsilon from 13.1 to 11 (similar to19%) and tan delta from 0.003 to 0.001. These properties depend approximately linearly on nitrogen content and glass density, but with different slopes for lanthanides and for Sc, Y and La group. Density changes were found to result from the atomic weight of the corresponding RE rather than from network tightening due to the dependence on RE ionic size. In contrast, nitrogen causes only small density increase but significant tightening of glass network and more effective changes of the studied properties than RE additives. The mechanisms in which non-lanthanide additives affect glass properties may be different from that of lanthanide modifiers.