No abstract

In this work, we present the opportunity to prepare perovskite materials in powder and in balls by solgel process. BaTiO 3 as spheres of 1-2 mm in diameter, presenting the same physico-chemical properties than powders, have been prepared by an oil-drop process. The shape forming of a dielectric material permits its use in a plasma reactor and promotes the efficiency of the system.

Sol–gel methods were used to synthesize BaTiO3 and LixTiyNi(1–x) materials. Processes using these sols were adjusted to coat spherical alumina pellets. The annealing temperature was studied in detail. This study also focuses on the characterization of the deposits. Data obtained by XRD, scanning electron microscopy, Raman spectroscopy, and gravimetric analyses were compared. Multiple impregnations were necessary to achieve a satisfactory deposit of the dielectric material. For Li0.10Ti0.02Ni0.88O, these sol–gel methods led to an impregnation depth of 50 μm, whereas for BaTiO3 a homogeneous deposit of only 5 μm was obtained. A special treatment with an ammonia solution was required to efficiently disperse BaTiO3. This preparation method achieved a spherical deposit of the dielectric material. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)