IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0492791
(2002-10-16)
|
등록번호 |
US-7337527
(2008-03-04)
|
우선권정보 |
IT-TO2001A0994(2001-10-19) |
국제출원번호 |
PCT/EP02/011567
(2002-10-16)
|
§371/§102 date |
20040416
(20040416)
|
국제공개번호 |
WO03/035575
(2003-05-01)
|
발명자
/ 주소 |
- Grasso,Giovanni
- Malagoli,Andrea
|
출원인 / 주소 |
- INFM Istituto Nazionale per la Fisica Della Materia
|
대리인 / 주소 |
|
인용정보 |
피인용 횟수 :
4 인용 특허 :
2 |
초록
▼
A method of manufacturing superconducting wires based on MgB2 is described and includes the steps of: production of a cylindrical wire comprising an MgB2 core surrounded by a metal covering, in which the core has a lattice structure formed by grains of the compound MgB2; rolling of the wire to produ
A method of manufacturing superconducting wires based on MgB2 is described and includes the steps of: production of a cylindrical wire comprising an MgB2 core surrounded by a metal covering, in which the core has a lattice structure formed by grains of the compound MgB2; rolling of the wire to produce a conductor in tape form; and subsequent heat treatment by heating to a temperature of between 800�� C. to 870�� C. This last step helps to increase the connection between the MgB2 grains whilst retaining the structural defects produced in the rolling step, thus producing a superconducting wire with greater current-transport capacity.
대표청구항
▼
What is claimed is: 1. A method of manufacturing superconducting wires (10) based on MgB2, including the steps of: production of a cylindrical wire (20) of predefined transverse dimensions, comprising an MgB2 core (11) surrounded by a metal covering (12), in which the core (11) has substantially a
What is claimed is: 1. A method of manufacturing superconducting wires (10) based on MgB2, including the steps of: production of a cylindrical wire (20) of predefined transverse dimensions, comprising an MgB2 core (11) surrounded by a metal covering (12), in which the core (11) has substantially a lattice structure formed by grains of the compound MgB2, the wire (20) being obtainable by drawing of a metal tube (14) into which are introduced beforehand the compound MgB2 or its elemental precursors, subsequently subjected to reaction, and rolling of the wire (20) to produce a conductor (10) in tape form, at the same time producing structural defects in the lattice of MgB2 grains, characterized in that it comprises a step of heat treatment of the conductor (10) in tape form by heating to a temperature of between 800�� C. and 870�� C. so as to increase the connection between the MgB2 grains whilst substantially maintaining the structural defects produced in the rolling step, wherein a further step of heat treatment of the cylindrical wire (20) by heating to a temperature of between 800�� C. and 870�� C. precedes said rolling step; and wherein the heat treatment step is performed in several stages in the course of the rolling step. 2. A method according to claim 1 in which the cylindrical wire (20) is produced by drawing of a metal tube (14) into which powders of the superconducting compound MgB2 are introduced beforehand. 3. A method according to claim 1 in which the cylindrical wire (20) is produced by drawing of a metal tube (14) into which a mixture of magnesium and boron powders in a stoichiometric ratio of 1:2 is introduced beforehand, the mixture being subjected to reaction to synthesize the compound MgB2 after the drawing operation. 4. A method according to claim 2, characterized in that the heat treatment is achieved by heating in an oven for a period of about 1 hour in an atmosphere of argon and oxygen. 5. A method according to claim 2, characterized in that the heat treatment is achieved by heating, by the Joule effect, of successive portions of conductor (10), kept in a partial vacuum, for a period of about 1 minute for each portion of conductor (10). 6. A method according to claim 5 in which, in the course of the heat treatment step, the conductor (10) is moved between a pair of metal pulleys in which an electrical current flows, which current is of an intensity such as to produce a region of heating of the conductor (10) in the vicinity of the pulleys. 7. A method according to claim 2, characterized in that the drawing step is performed with successive steps of approximately 10% reduction of the cross-sectional area of the conducting wire (20), to reach a wire diameter value of between about 0.5 mm and 3 mm. 8. A method according to claim 1, characterized in that the metal tube (14) has an outside diameter of between about 6 mm and 30 mm, and in that the thickness of the wall of the tube (14) is selected, in dependence on its outside diameter, in a manner such that the central hole represents from about 20% to 50% of the total volume of the tube (14). 9. A method according to claim 2, characterized in that the metal tube (14) is made of iron, nickel, copper, or alloys thereof. 10. A method according to claim 3, characterized in that the metal tube (14) is made of iron. 11. A method according to claim 1, characterized in that the step of introducing powders of the compound MgB2 or of its elemental precursors into the metal tube (14) is followed by a step of compaction of the powders by the application of a pressure of about 100 MPa. 12. A method according to claim 11, characterized in that the powder compaction step is carried out in a controlled atmosphere. 13. A method according to claim 11, characterized in that, after the powder compaction step, the ends of the tube (14) are sealed with deformable plugs made of tin or lead. 14. A method of manufacturing superconducting wires (10) based on MgB2, including the steps of: production of a cylindrical wire (20) of predefined transverse dimensions, comprising an MgB2 core (11) surrounded by a metal covering (12), in which the core (11) has substantially a lattice structure formed by grains of the compound MgB2, the wire (20) being obtainable by drawing of a metal tube (14) into which are introduced beforehand the compound MgB2 or its elemental precursors, subsequently subjected to reaction, and rolling of the wire (20) to produce a conductor (10) in tape form, at the same time producing structural defects in the lattice of MgB2 grains, characterized in that it comprises a step of heat treatment of the conductor (10) in tape form by heating to a temperature of between 800�� C. and 870�� C. so as to increase the connection between the MgB2 grains whilst substantially maintaining the structural defects produced in the rolling step, wherein the rolling step is performed with successive steps of approximately 10% reduction in the thickness of the conductor wire (20), to reach a value of the thickness of the flattened conducting wire (10) of the order of about 0.3 mm. 15. A method of manufacturing superconducting wires (10) based on MgB2, including the steps of: production of a cylindrical wire (20) of predefined transverse dimensions, comprising an MgB2 core (11) surrounded by a metal covering (12), in which the core (11) has substantially a lattice structure formed by grains of the compound MgB2, the wire (20) being obtainable by drawing of a metal tube (14) into which are introduced beforehand the compound MgB2 or its elemental precursors, subsequently subjected to reaction, rolling of the wire (20) to produce a conductor (10) in tape form, at the same time producing structural defects in the lattice of MgB2 grains, heat treating the conductor (10) in tape form by heating to a temperature of between 800�� C. and 870�� C. so as to increase the connection between the MgB2 grains whilst substantially maintaining the structural defects produced in the rolling step, wherein the cylindrical wire (20) is produced by drawing of a metal tube (14) into which powders of the superconducting compound MgB2 are introduced beforehand and wherein the rolling step is preceded by a series of consecutive steps, comprising: the grouping in a bundle of a plurality of cylindrical conductor wires (20) produced by a drawing operation, the arrangement of the bundle thus formed in a second metal tube (24), and a second drawing step, so as to produce a multi-filament conductor.
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