Synthesis and characterization of 50BaO-(5-x) Al2O3 - xR2O3-30B2O3 -15SiO2 (R = Nd, Gd) glass-ceramics

Glass-ceramics of composition 50BaO-(5-x) Al2O3-xR(2)O(3)-30B(2)O(3)-15SiO(2) (x = 0, 1, 2, 3,4,5 and R = Nd, Gd) have been synthesized by conventional melt quenching method followed by controlled heat treatment. The glass transition temperature (T-g) and crystallization temperature (T-c) have been observed from the Differential Thermal Analysis (DTA). The density of glasses and glass-ceramics has been measured. X-ray diffraction (XRD) technique has been used to confirm the amorphous nature of the glasses and to identify the crystalline phases formed in glass-ceramics. The structural changes due to heat-treatment have been investigated using Fourier Transform Infrared (FT-IR). The coefficient of thermal expansion (CTE) of glasses lie within the range (11.40 - 11.81) x 10(-6)/degrees C, and increased to (12.32 - 12.81) x 10(-6)/degrees C for glass-ceramics. Microhardness values lie in the range 9.34 - 9.48 GPa. Owing to the suitable thermal properties these glass-ceramics can be considered as suitable materials as sealants for Solid Oxide Fuel Cells (SOFC).