Method for making ceramic-metal composites and the resulting composites

Abstract

The invention provides methods to manufacture dense, complex c-axis oriented ceramic oxide layers with thickness greater than 2.5 microns (.mu.m) on a metallic substrate (composites) without the use of an interfacial barrier, buffer, or surface layer using a metalorganic deposition process and thermomechanical reaction treatments is disclosed. A porous amorphous metal oxide ceramic deposit is formed directly on the substrate by spray pyrolyzing a mixed metalorganic precursor solution onto the metallic substrate. The metallic substrate has been previously heated to temperatures greater than the boiling point of the organic solvent and are high enough to initiate in situ decomposition of the metalorganic precursor salts. The process does not apply the precursor solution to the substrate as a liquid coating that is pyrolyzed in subsequent processing steps. The resultant porous amorphous oxide deposit is processed into a dense amorphous ceramic, or a fully crystallized c-axis oriented ceramic through a series of mechanical compression and short reaction treatments that are used to crystallize the amorphous ceramic layer. The inventive method applies to making complex ceramic oxides including superconducting compositions of bismuth cuprate ceramic, piezoelectric or insulating compositions. The composites so produced are useful in devices that include ceramic sputtering targets, heat shields, electrically conducting wires, magnetic solenoids, electromagnetic shielding, and energy storage devices. The invention also provides the ceramic-metal composites so made.