Qi T Li

6370762, Apr 16, 2002

May 21, 1996

08/651688

Qi Li - Waltham MA
Theodore S. Greene - Seekonk MA
William J. Michels - Brookline MA
William L. Carter - Chelmsford MA

American Superconductor Corp. - Westborough MA

H01L 3924

29599, 505100, 505231

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.

6537689, Mar 25, 2003

Nov 26, 2001

09/995420

Suresh Annavarapu - Brookline MA
Martin W. Rupich - Framingham MA
Xiaoping Li - Westborough MA
Wei Zhang - Shrewsbury MA
Edward J. Siegal - Malden MA
Qi Li - Marlborough MA

American Superconductor Corporation - Westborough MA

C09K 1900

428701, 428930, 505237, 505238

The invention relates to multi-layer articles and methods of making such articles. The multi-layer superconductors can have one or more layers with an oriented termination plane. The methods include first conditioning the termination plane of an underlying layer, such as a buffer layer or a superconductor layer, then disposing a layer of material on the conditioned termination plane. The conditioned termination plane can be a high quality termination plane. Superconductor articles formed by these methods can exhibit relatively high critical current densities.

20020019316, Feb 14, 2002

Feb 12, 2001

09/781371

Qi Li - Waltham MA, US
William Michels - Brookline MA, US
Ronald Parrella - Natick MA, US
Gilbert Riley - Marlborough MA, US
Mark Teplitsky - Westborough MA, US
Steven Fleshler - Brookline MA, US

H01B012/00

505/230000, 505/231000, 505/431000, 505/501000

The present invention provides a (Bi,Pb)SCCO-2223 oxide superconductor composite which exhibits improved critical current density and critical current density retention in the presence of magnetic fields. Retention of critical current density in 0.1 T fields (77 K, ⊥ ab plane) of greater than 35% is disclosed. Significant improvements in oxide superconductor wire current carrying capacity in a magnetic field are obtained by subjecting the oxide superconductor composite to a post-processing heat treatment which reduces the amount of lead in the (Bi,Pb)SCCO-2223 phase and forms a lead-rich non-superconducting phase. The heat treatment is carried out under conditions which localize the lead-rich phase at high energy sites in the composite.

20020193255, Dec 19, 2002

Apr 16, 2002

10/123540

Qi Li - Waltham MA, US
Theodore Greene - Seekonk MA, US
Gilbert Riley - Marlborough MA, US
William Michels - Brookline MA, US
William Carter - Chelmsford MA, US

C01F001/00
H01F001/00

505/510000, 505/809000

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 Jmay 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.

63113864, Nov 6, 2001

Jul 21, 1999

9/358245

Qi Li - Waltham MA
Eric R. Podtburg - Natick MA
Patrick John Walsh - Newton MA
William L. Carter - Chelmsford MA
Gilbert N. Riley - Marlborough MA
Martin W. Rupich - Framingham MA
Elliott Thompson - Coventry RI
Alexander Otto - Chelmsford MA

American Superconductor Corporation - Westborough MA

H01L 3929

29599

A novel process of the production and processing of high quality, high T. sub. c (Bi,Pb)SCCO superconductors starts with fabrication of a precursor article including selected intermediate phases with desired chemical and structural properties. The precursor fabrication includes introducing the reacted mixture having a dominant amount of the tetragonal BSCCO phase into a metal sheath, and sealing the reacted mixture within said sheath, heating the mixture at a second selected processing temperature in an inert atmosphere with a second selected oxygen partial pressure for a second selected time period, the second processing temperature and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture. The sealed sheath is deformed to form an elongated precursor article of a desired texture; and thereafter heated at a third selected processing temperature in an inert atmosphere with a third selected oxygen partial pressure for a third selected time period. The third processing temperature and third oxygen partial pressure are cooperatively selected to convert at least a portion of the orthorhombic BSCCO phase to the final superconducting BSCCO material.

62472240, Jun 19, 2001

Jun 6, 1995

8/468089

Qi Li - Waltham MA
Eric R. Podtburg - Natick MA
Patrick John Walsh - Newton MA
William L. Carter - Chelmsford MA
Gilbert N. Riley - Marlborough MA
Martin W. Rupich - Framingham MA
Elliott Thompson - Coventry RI
Alexander Otto - Chelmsford MA

American Superconductor Corporation - Westborough MA

H01L 3924

29599

A method is described to prepare a highly textured oxide superconductor article in a single deformation-sinter process. A precursor article including a plurality of filaments comprising a precursor oxide having a dominant amount of a tetragonal BSCCO 2212 phase and a constraining member substantially surrounding each of the filaments is provided. Each of the filaments extends along the length of the article. The oxide article is subjected to a heat treatment at an oxygen partial pressure and temperature selected to convert a tetragonal BSCCO 2212 oxide into an orthorhombic BSCCO 2212 oxide and, thereafter, roll worked in a high reduction draft in a range of about 40% to 95% in thickness so that the filaments have a constraining dimension is substantially equivalent to a longest dimension of the oxide superconductor grains. The rolled article is sintered to obtain a BSCCO 2223 oxide superconductor.

57983186, Aug 25, 1998

May 21, 1996

8/651169

Qi Li - Waltham MA
William J. Michels - Brookline MA
Ronald D. Parrella - Natick MA
Gilbert N. Riley - Marlborough MA
Mark D. Teplitsky - Westborough MA
Steven Fleshler - Brookline MA

American Superconductor Corp. - Westborough MA

H01B 1202
H01L 3924

505501

The present invention provides a (Bi,Pb)SCCO-2223 oxide superconductor composite which exhibits improved critical current density and critical current density retention in the presence of magnetic fields. Retention of critical current density in 0. 1 T fields (77 K,. perp. ab plane) of greater than 35% is disclosed. Significant improvements in oxide superconductor wire current carrying capacity in a magnetic field are obtained by subjecting the oxide superconductor composite to a post-processing heat treatment which reduces the amount of lead in the (Bi,Pb)SCCO-2223 phase and forms a lead-rich non-superconducting phase. The heat treatment is carried out under conditions which localize the lead-rich phase at high energy sites in the composite.

59424664, Aug 24, 1999

Jun 6, 1995

8/467033

Qi Li - Waltham MA
Eric R. Podtburg - Natick MA
Patrick John Walsh - Newton MA
William L. Carter - Chelmsford MA
Gilbert N. Riley - Marlborough MA
Martin W. Rupich - Framingham MA
Elliott Thompson - Coventry RI
Alexander Otto - Chelmsford MA

American Superconductor Corporation - Westborough MA

H01L 3924

505431

A novel process of the production and processing of high quality, high T. sub. c (Bi,Pb)SCCO superconductors starts with fabrication of a precursor article including selected intermediate phases with desired chemical and structural properties. The precursor fabrication includes introducing the reacted mixture having a dominant amount of the tetragonal BSCCO phase into a metal sheath, and sealing the reacted mixture within said sheath, heating the mixture at a second selected processing temperature in an inert atmosphere with a second selected oxygen partial pressure for a second selected time period, the second processing temperature and the second oxygen partial pressure being cooperatively selected to form a dominant amount of an orthorhombic BSCCO phase in the reacted mixture. The sealed sheath is deformed to form an elongated precursor article of a desired texture; and thereafter heated at a third selected processing temperature in an inert atmosphere with a third selected oxygen partial pressure for a third selected time period. The third processing temperature and third oxygen partial pressure are cooperatively selected to convert at least a portion of the orthorhombic BSCCO phase to the final superconducting BSCCO material.