The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 16, 2002
Filed:
May. 21, 1996
Qi Li, Waltham, MA (US);
Theodore S. Greene, Seekonk, MA (US);
Gilbert N. Riley, Jr., Marlborough, MA (US);
William J. Michels, Brookline, MA (US);
William L. Carter, Chelmsford, MA (US);
American Superconductor Corp., Westborough, MA (US);
Abstract
A reduced coefficient of friction, preferably created by ideal lubrication conditions, may advantageously be employed in the breakdown deformation of a precursor to a multifilamentary superconducting composite, particularly in combination with one or more high reduction breakdown drafts, to improve composite homogeneity and significantly increase the range of deformation conditions over which dimensional tolerances and J may be optimized. Precursor composites made by this method exhibit reduced microhardness variability and fewer and less serious transverse filament defects than composites made by prior art methods. The method comprises the steps of: first, providing a precursor article comprising a metal matrix surrounding a plurality of filaments extending along the length of the article and comprising precursors to a desired superconducting ceramic; next, roll working the precursor article during a breakdown stage at a predetermined pressure and a coefficient of friction less than about 0.2, preferably less than 0.01, and preferably less than about 0.001 during each roll working draft, and, then, sintering the rolled article to obtain the desired superconducting ceramic. The coefficient of friction is preferably obtained by interposing a lubricant between the precursor article and one or more rolls, most preferably under conditions which create ideal lubrication conditions.