Effect of Er2O3 and ErF3 on the structural and elastic properties of sodium oxyfluoroborate glasses

Glasses based on 0.70B2O3–(0.15-x)Na2O–0.15NaF–x(Er2O3 or ErF3), where x = 1, 2 and 3 mol% have been prepared by melt quench technique. Density was measured and molar volume calculated. The density and molar volume increase with the increase in Er2O3 and ErF3 content. The IR spectra were measured to investigate the structure of the glasses. The glass structure is composed from BO3 trigonal and BO4, BO3F, BO2F2 or BOF3 tetrahedral units. Longitudinal and transverse velocities have been measured by using pulse echo technique. The longitudinal, shear, Young’s, bulk moduli, Poisson’s ratio and microhardness were calculated. The velocities and elastic moduli increase with the increasing of Er2O3 while they decrease with the increasing of ErF3. Acoustical impedance and some thermodynamic parameters like latent heat for melting, diffusion constant, Debye and softening temperatures have been calculated in order to see the effect of both Er2O3 and ErF3 on these parameters. The longitudinal and shear strain were calculated and the elastic resistance for glass deformation were also determined.

► The structure of the glasses composed from BO3 trigonal, BO4, BO3F, BO2F2 or BOF3 tetrahedra.
► The ultrasonic velocity and elastic moduli increased in Er2O3 doped glasses while they decreased in ErF3 glasses.
► The acoustic impedance of wave propagation in Er2O3 glass is increased while it decrease in ErF3 glass.