Effects of Lanthanide Substitution on the Sintering Behavior of Bismuth Titanate Ceramics Prepared by the Chemical Coprecipitation Method

Bi4-xLnxTi3O12 (Ln = La, Nd or Gd; x = 0, 0.25, 0.5, 0.75 or 1.0) fine powders were prepared by the chemical coprecipitation method. Suitable calcination temperature for each powder was determined. The effects of Ln-substitution on the sintering behaviors, crystal structures, lattice constants and microstructures of sintered bodies were investigated. The crystallization temperature was significantly influenced by lanthanide elements and their amounts, and thus, a suitable temperature for calcination was determined for each substitution. Each calcined powder was milled and fired at 950, 1000, 1050 or 1100°C for 2 hr. It was found that the Ln-substitution drastically inhibited both sintering and grain growth, although the effect was not consistent with the order of Ln ionic radii.