Engineered sintering aids for PbO-based electroceramics

Borate- and silicate-based glasses that devitrify on heating to form ferroelectric lead titanate have been developed. Their potential for use as sintering aids in PbO-based electroceramics has been evaluated by studying the densification of PbTiO3 (PT) with increasing wt.% addition of glass powder. When ≥3 wt.% of a borate-based glass was added, ≥94% theoretical density was achieved at 1,100 °C but for a silicate-based glass system 10 wt.% glass addition was required to achieve the same density. As the wt.% glass content increased the maximum and room temperature permittivity decreased and there was also a decrease in T c and the c/a ratio. The decrease in T c is believed to be due to increased clamping from neighbouring grains as the density of the PT increases. The decrease in maximum and room temperature permittivity is related to the presence of secondary phases.