Inorganic thin films prepared from soluble powders and their applications

Sol-gel processing has proved to be a useful method for the preparation of a wide range of inorganic thin films. However, gelation or precipitation of coating solutions and thus limited shelf-life have been drawbacks for the industrial application of this technology. Soluble powders of various compositions can be prepared from modified metal alkoxides commonly employed in sol-gel processing. Even though these powde rs contain a considerable amount of organic moieties they can be stored ind efinitely under ambient conditions, thus diminishing shelf life problems. R edissolution in polar organic solvents, solvent mixtures or even water yiel ds ready-to-use coating solutions. Coating solutions for the preparation of titania (TiO2), zirconia (ZrO2) and lead zirconate titanate (PbTixZr1-xO3, PZT) films have been synthesized by this method. Thickness, microstructure and properties of the resulting films can be varied by modification of the solvent, the coating procedure and thermal treatment. Inorganic thin films for various applications have been prepared.