Electrical and thermal properties of lead titanate glass ceramics

Glass samples with composition of (50−X)PbO-(25+X)TiO₂-25B₂O₃ (where X=0, 5, 10 and 12.5 mol%) were prepared using conventional quenching technique. The glass transition temperature, T_g and crystallization temperature T_c were determined from the DTA. These glass samples were converted to glass ceramics by following two stage heat treatment schedule. The glass ceramic samples were characterized by XRD, SEM and dielectric constant measurements. The XRD results revealed the formation of ferroelectric lead titanate (PT) as a major crystalline phase in the glass ceramics. The density increases and the CTE decreases for all glass ceramics with increase in X (mol%). This may be attributed to increase in PT phase. The SEM results which show rounded crystallites of lead titanate, also supports other results. Hysteresis loops observed at room temperature confirms the ferroelectric nature of glass ceramics. The optimized glass ceramic sample exhibits high dielectric constant which is of technical importance.