EFFECT OF SrO CONTENT ON THE STRUCTURE AND ELASTIC BEHAVIOR OF xSrO-(90-x)B2O3-2CeO2-8Al2O3 GLASS

Abstract

Strontium cerium aluminium borate glass samples with composition xSrO-(90-x)B2O3 2CeO2-8Al2O3 (x=25, 30, 35, 40, 45 and 50 mol%) were prepared by melt-quenching method to investigate the elastic behavior and phase formation. XRD data showed amorphous and mixed crystalline/amorphous phases for the samples with SrO concentration x ≤ 35 mol% and x > 35 mol%, respectively. FESEM image and EDX analysis revealed that the samples contained Ce-rich crystalline phase and Ce depleted glass phase. FTIR analysis showed that the glass consisted of BO4 and BO3 structural units. Addition of SrO has resulted in increased ultrasonic velocities, longitudinal modulus (CL), shear modulus (µ), bulk Modulus (K), Young’s modulus (Y) and hardness (H) at x ≤ 35 mol%. The increase in the elastic moduli indicates increase of network rigidity of the glass system, related to the borate anomaly where the coordination number increased with the addition of SrO. Decrease in elastic moduli related to formation of NBO and formation of grain / phase boundaries due to mixed crystalline / amorphous phases at higher SrO addition. Quantitative analysis of ultrasonic data using the bulk compression and ring deformation models showed reduction in the ratio of calculated bulk modulus to the experimental bulk modulus, Kbc/Ke indicating decreased ring deformation in borate anomaly region.