The Effect of Processing Parameters on Properties of Bi2GeO5 Glass Ceramics
In this research, it is interesting to fabricate glass ceramics containing lead free ferroelectric crystals. The new lead free ferroelectric phase of interest is orthorhombic Bi2GeO5 which are precipitated in the BiO1.5-GeO2-BO1.5 system and studied in the region of 60 mol% BiO1.5:20 mol% GeO2: 20 mol% BO1.5. The glasses were prepared by conventional melt-quenching method. The glasses were melted separately in Pt and Al2O3 crucible in an air atmosphere. It is found that the as-received glasses were easily obtained from Al2O3 crucible while that from Pt crucible devitrification of Bi2GeO5 crystals were observed in some glasses, giving rise to an instability and difficulty in obtaining good based glasses by using this Pt crucible. The glass ceramics prepared from Pt crucible crystallized into two phases of the expected Bi2GeO5 and second phase Bi4Ge3O12 while Bi2GeO5 phase only observed in the glass ceramics prepared from Al2O3 crucible. Crystallinity and phases of the glass ceramics have a significant effect on their dielectric properties.
P. Kantha et al., "The Effect of Processing Parameters on Properties of Bi2GeO5 Glass Ceramics ", Advanced Materials Research, Vols. 55-57, pp. 437-440, 2008