Metalorganic deposition process for preparing superconducting oxide films
AssigneeEastman Kodak Company
InventorsJose M. Mir, John A. Agostinelli, David L. Peterson, Gustavo R. Paz-Pujalt, Brian J. Higberg, Gopalan Rajeswaran
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Abstract
A metalorganic deposition method is disclosed for manufacturing a superconducting oxide film on a substrate, in which a mixed metalorganic precursor is coated and heated to its thermal decomposition temperature to create an amorphous mixed metal oxide layer. The amorphous layer is then converted to a crystalline coating by further heating followed by cooling in the presence of O.sub.2 atmosphere.
Claims46
A process of forming a uniform electrically conductive metal oxide coating on a substrate comprising
- applying to the substrate a coating of a solution consisting essentially of a volatilizable film forming solvent, an organic film promoting agent chosen from the class consisting of 2-ethylhexanoic acid, rosin, ethyl lactate, 2-ethoxyethyl acetate, and a terpene containing from 10 to 30 carbon atoms, metal-ligand compounds of each of rare earth and alkaline earth containing at least one thermally volatilizable organic ligand, and at least one copper-ligand compound containing a thermally volatilizable carboxylate ligand,
- removing the solvent, organic film promoting agent, and ligands from the substrate by heating in the presence of oxygen to form an amorphous rare earth alkaline earth copper oxide coating of less than 1 .mu.m in thickness on the substrate and
- forming a crystalline conductive metal oxide coating on the substrate.
A process of preparing an article comprised of a substrate and a crystalline electrically conductive rare earth alkaline earth copper oxide coating on the substrate exhibiting a T.sub.c in excess of 30.degree. K. comprising
- choosing the substrate from the class consisting of strontium titanate, magnesia, and alumina,
- applying to the substrate a coating of a solution consisting essentially of a volatilizable film forming solvent, metal-ligand compounds of each of rare earth and alkaline earth containing at least one thermally volatilizable organic ligand, and at least one copper-ligand compound containing a thermally volatilizable carboxylate ligand,
- removing the solvent and organic ligands from the substrate by heating in the presence of oxygen to form a coating of less than 1 .mu.m in thickness, and
- forming a crystalline conductive metal oxide coating on the substrate by heating to a temperature in the range of from 900.degree. to 1100.degree. C. followed by contact with air or an oxygen enriched atmosphere during cooling.
A process of preparing an article comprised of a substrate and a coating on the substrate exhibiting a T.sub.c in excess of 30.degree. K. containing greater than 45 percent by volume a tetragonal K.sub.2 NiF.sub.4 crystalline phase satisfying the metal ratio:
- L.sub.2-x :M.sub.x :Cu
- where
- L is lanthanum,
- M is alkaline earth metal which is at least one of barium and strontium, and
- x is 0.05 to 0.30,
- said process comprising
- coating onto the substrate a solution consisting essentially of a volatilizable film forming solvent and metal-ligand compounds of each of the lanthanum, alkaline earth, and copper containing at least one thermally volatilizable ligand,
- removing the solvent and ligands from the, substrate, this step including heating in the presence of oxygen to form an amorphous lanthanum alkaline earth copper oxide coating on the substrate,
- heating the amorphous coating to a temperature in the range of from 925.degree. to 975.degree. C. to form the crystalline phase,
- effecting crystal growth by heating in the temperature range of from 975.degree. to 1050.degree. C., and
- cooling the coating in the presence of oxygen at a rate of less than 25.degree. C. per minute until it reaches a temperature of from 550.degree. to 450.degree. C.
A process of preparing an article comprised of a substrate and a coating on the substrate exhibiting a T.sub.c in excess of 30.degree. K. containing at least 45 percent by volume of an orthorhombic crystalline phase satisfying the metal ratio:
- Y:M.sub.2 :Cu.sub.3
- where
- M is barium, optionally in combination with at least one of strontium and calcium,
- said process comprising,
- coating onto the substrate a solution consisting essentially of a volatilizable film forming solvent and metal-ligand compounds of each of the metals Y, M, and Cu containing at least one thermally volatilizable ligand, said metal-ligand compound of copper being a copper carboxylate,
- removing the solvent and ligands from the substrate, this step including heating in the presence of oxygen to form an amorphous rare earth alkaline earth copper oxide coating on the substrate,
- heating the amorphous coating to a temperature in the range of from 900.degree. to 950.degree. C. to form the crystalline phase, and
- cooling the coating in the presence of oxygen at a rate of less than 25.degree. C. per minute until it reaches a temperature of from 750.degree. to 400.degree. C.
Dependencies are inferred from the claim text.