Contact Strength of the RE-Oxynitride Glasses

Effects of the rare-earth additives (RE = Sc, Y, La, Nd, Gd, Sm, Yb and Lu) and nitrogen on contact strength of the oxide and oxynitride glasses were investigated at room temperature. The advantage of this relatively new technique is its experimental simplicity and using of miniature samples, however, a relatively complex stress distribution around the contact points reduces Weibull parameter in comparison with the conventional bending strength. Contact strength of the tested glasses is also strongly influenced by surface finish. The differences in the effects of REmodifiers in oxide and oxynitride glasses suggest that the contributions from RE and nitrogen may not be simply additive, as observed earlier for various thermo-mechanical properties. However, additional study is necessary to eliminate the effects of surface defects to support this assumption.