Pitfalls in the synthesis of nanoscaled perovskite type compounds.: Part I:: Influence of different sol-gel preparation methods and characterization of nanoscaled BaTiO3

Different sol-gel routes are compared for the synthesis of nanoscaled BaTiO3 with respect to the reaction paths and the quality of the products. The various precursor systems differ largely in their behaviour during decomposition imposing quite different procedures for their thermal treatment. It is shown that the compositional homogeneity during the process of synthesis, which is the target of sol-gel methods, may well be destroyed by the formation of intermediate compounds. It will only be restored after prolonged heating at higher temperatures where the crystallite sizes will in general have left the nanoregime. Due to such pitfalls the desired properties of the products with narrow size distributions will not always be ensured when working according to such recipes and the products obtained will behave quire differently in fabrication procedures like shaping and sintering of workpieces, (C) 2001 Elsevier Science Ltd. All rights reserved.