Patent Number: 6,310,297

Title: Strongly-linked oxide superconductor and a method of its manufacture

Abstract: A strongly-linked polycrystalline oxide superconductor article includes an oxide superconductor selected from the group consisting 124-type and 247-type oxide superconductors having fine, highly aligned oxide superconductor grains less than .mu.m long a longest dimension. The oxide superconductor article has at least a 25% retention of critical current density in a 0.1 Tesla field. A method for preparing a strongly-linked oxide superconductor includes shaping a finely divided metallic precursor of an oxide superconductor; oxidizing the finely divided metallic precursor to produce a finely divided sub-oxide species while avoiding conversion of an appreciable amount of the sub-oxide species into the oxide superconductor, annealing and deforming the article, in either order, the annealing carried out at a temperature and for a time sufficient to convert some of the sub-oxide species into fine grains of the oxide superconductor thereby forming a mixture of sub-oxide species and oxide superconductor and the deformation carried out such that the fine grains of oxide superconductor are rotated into alignment parallel to an intended current carrying direction of the article without fracturing or pulverization of the oxide superconductor grains; alternating annealing and deformation of the article until no further improvement in alignment is observed; and subjecting the aligned grains to a final anneal in order to react any remaining sub-oxide species and maximize the growth and sintering of existing aligned grains.

Inventors: Masur; Lawrence J. (Needham, MA), Podtburg; Eric R. (Newton, MA)

Assignee: American Superconductor Corp.

International Classification: C04B 35/45 (20060101); C04B 35/65 (20060101); C04B 35/01 (20060101); H01L 39/24 (20060101); H01B 012/00 ()

Expiration Date: 10/30/2018