Diffusion and Reactivity in Perovskite Materials of the Composition (Pb,La) (Zr,Ti)O₃

Abstract

Problems are encountered in the synthesis of homogeneous and dense (lanthana doped) leadzirconate-titanate ceramics. Keizer et al. (1) and Buckner et al. (2) have mentioned inhomogeneities in the distribution of Zr⁴⁺- and Ti⁴⁺-ions among the available lattice sites. Keizer et al. (1) and Carl et al. (3) have reported the occurrence of a minimum in the ceramic grain size and density after firing at a lanthanum content of 2–4 at%. Haertling (4) and Snow (5) have observed that sinterreactivity is strongly promoted by adding a surplus of PbO to the reacting powder mixture. The dielectric and ferroelectric properties of these ceramics are dependent on micro structural parameters homogeneity, grain size and density. Hence a better understanding of the reactions that lead to different microstructures is important.