Substitution of lead into the bismuth oxide layers of the n = 2- and n = 3-aurtvillius phases

Ceramic materials of the n = 2- and n = 3-Aurivillius phases of type Bi2SrM2O9 and Bi4Ti3O12 were systematically substituted by Pb2+. The simultaneous charge compensated incorporation was performed for n = 2 with the nominal compositions Bi2 − xPbxSr1 − xLaxM2O9 and Bi2 − xPbxSr M2 − xWxO9 as well as for the single lead substituted systems Bi2 − xPbxSrM2O9 − δ with M = Nb, Ta (0 ≤ x ≤ 1). For n = 3 the following groups of materials were synthesized: Bi4−xPbxTi3 − xNbxO12, Bi2 − xPbxLa2Ti3−xNbxO12, Bi2 − xPbx Sr2 − xLaxTiNb2O12 (0 ≤ x ≤ 1) and Bi2Sr2 − yPbyTiNb2O12 (0 ≤ y ≤ 2). The powder X-ray diffraction diagrams were single phased for all materials, thus exhibiting a solid solution behavior over the whole range of substitution but for the single lead substituted n = 2 systems. Structural investigations by X-ray powder diffractometry were carried out with different space groups and ordering schemes in order to verify the incorporation of the isoelectronic Pb2+ for Bi3+ in the bismuth oxide layers. A partially disordered distribution of La, Pb and Bi in Bi2 − xPbxLa2Ti3 − xNbxO12 and ordering effects of Ti/Nb in Bi2 Sr2 − yPbyTiNb2O12 were indicated.