Effect of Excess PbO on the Sintering Characteristics and Dielectric Properties of Pb(Mg _1/3 Nb _2/3 )O ₃ –PbTiO ₃ ‐Based Ceramics

Abstract

Additions of excess PbO to the perovskite Pb[(Mg 1/3 Nb 2/3 ) 0.92 Ti 0.08 ]O 3 solid solution enhanced the formation of a liquid phase at 840°C, which served as a densification aid for the ceramics. The liquid phase allowed elimination of pores and promoted grain growth during sintering. With additions of 1 to 2 wt% excess PbO, densities in excess of 97% of theoretical were obtained at a sintering temperature of 950°C. The peak dielectric constants of the resulting ceramics were over 18 000 at 30°C and dissipation factors less than 1%. Additions of PbO in excess of 2 wt% resulted in inferior dielectric properties due mainly to the dilution of the ferroelectric phase.