MICROSTRUCTURE AND PROPERTIES OF CR2O3-DOPED TERNARY LEAD-ZIRCONATE-TITANATE CERAMICS

The effects of Cr2O3 doping (0 to 0.6 wt%) on the microstructure and electrical properties of ternary Pb0.97Sr0.03-[Zr0.458Ti0.452(Mn1/3Nb2/3)0.09]O3 piezoelectric ceramics have been studied. Abnormal grain growth (grain sizes of 2.8 to 28.5 mum) and densification (porosities of 2% to 12%) are found, and the tetragonality c/a nearly keeps constant whereas c and a slightly decrease in the doping range. The results for the temperature dependence of electric conductivity and the dielectric constant show that electric conductivity increases continuously over 0.1 wt% content, activation energies are all close to 0.92 eV in the paraelectric state, and the Curie temperature T(c) decreases with increasing doping content. Minor additives of less-than-or-equal-to 0.1 wt% improve the dielectric and piezoelectric properties, but with more additives of greater-than-or-equal-to 0.4 wt% electrical properties appear to deteriorate. Thus, these phenomena can be ascribed mainly lo anomalous developed microstructure.