EP2262346A1 - Use of oxide ceramic materials or metal ceramic compounds for electrical applications likes heaters - Google Patents

Use of oxide ceramic materials or metal ceramic compounds for electrical applications likes heaters Download PDF

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Publication number
EP2262346A1
EP2262346A1 EP09305525A EP09305525A EP2262346A1 EP 2262346 A1 EP2262346 A1 EP 2262346A1 EP 09305525 A EP09305525 A EP 09305525A EP 09305525 A EP09305525 A EP 09305525A EP 2262346 A1 EP2262346 A1 EP 2262346A1
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EP
European Patent Office
Prior art keywords
superconducting
heating element
oxide ceramic
material according
materials
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09305525A
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German (de)
French (fr)
Inventor
Jürgen EHRENBERG
Joachim Bock
Steffen Elschner
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Nexans SA
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Nexans SA
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Filing date
Publication date
Application filed by Nexans SA filed Critical Nexans SA
Priority to EP09305525A priority Critical patent/EP2262346A1/en
Publication of EP2262346A1 publication Critical patent/EP2262346A1/en
Withdrawn legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C1/00—Details
    • H01C1/02—Housing; Enclosing; Embedding; Filling the housing or enclosure
    • H01C1/034—Housing; Enclosing; Embedding; Filling the housing or enclosure the housing or enclosure being formed as coating or mould without outer sheath
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/10—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material
    • H05B3/14—Heater elements characterised by the composition or nature of the materials or by the arrangement of the conductor characterised by the composition or nature of the conductive material the material being non-metallic
    • H05B3/141—Conductive ceramics, e.g. metal oxides, metal carbides, barium titanate, ferrites, zirconia, vitrous compounds

Abstract

The present invention relates to the use of oxide ceramic materials or metal ceramic compounds, which have superconducting properties or can be converted to a superconducting state in non-superconducting electrical applications, for example as a material for resistive heaters.
The material is selected from alkaline earth cuprate, rare earth alkaline cuprate, iron pnictides and magnesium diboride. The shape body can be obtained by a melt casting process. The material could be used for a heating element an ohmic resistor or an electrode suitable in electrical arc discharged.

Description

  • The present invention relates to the use of specific oxide ceramic materials and metal ceramic compounds for electrical applications.
  • In particular, the present invention relates to the use of oxide ceramic materials and metal ceramic compounds suitable in the production of high temperature superconductors in non-superconducting electrical application.
  • Examples for non-superconducting electrical applications of such materials are the use thereof as heating elements, ohmic resistors or deposition of thin films by means of electrical arc discharge.
  • Resistive heating is a process by which passage of electric current through an element or body made of conductive material releases heat. Heating is caused by the interaction of the current and the material of the element or body, in the following referred to "heating element".
  • The heating capacity depends on the specific resistance of the material, the cross-sectional area and lengths of the heating element and the electrical current.
  • The possible current flow is restricted since care must be taken, that the current flow is not too high in order to avoid excessive heating until the melting point of the material.
  • Conventional heating elements are often in form of coils (heating coil) made of metals and metal alloys such as tungsten (W) and nickel-iron-alloys.
  • However, such conventional heating elements made of metals such as W suffer from oxidation. Furthermore, due to the metallic nature there ability to transform electrical power into heat is strongly dependent on operation temperature. They require often a voltage level of 220 V which, by far, exceeds the admissible contact voltage being uncritical for humans of 50 V (alternating voltage), and 120 V (direct voltage).
  • Further, during the heating process the metallic heating coils show a strong flexibility due to the high thermal expansion coefficient of metals and metal alloys. Therefore the metal windings of the coil have to be separated from each other for avoiding short cuts by using materials which are temperature resistant and insulating, such as aluminium oxide, glass, glass wool, rock woll, magnesium oxide, etc. These materials are often expensive and they are in the majority brittle. In the result, electrical devices using such heating elements become more expensive and/or are very sensitive to mechanical impacts.
  • Ohmic resistors made of metals and metal alloys for power application suffer from the weight and size caused through the metallic windings.
  • It has been known, that some carbides, nitrides and diborides of metals of the groups 4a and 5a have a low specific resistance of between 0.01 - 0.2 mohm*cm (mΩcm) (Münster A et al. "Über einige elektrische Eigenschaften von Titannitrid und Titancarbid" Zeitschrift für Physik, vol. 144, pages 139 to 151 (1956)). For example, the specific resistance of tungsten carbide (WC) is in the range of 0.017 to 0.022 mΩcm. Thus, the specific resistance of these materials equals the specific resistance of metals which is typically in the range of 0.01-0.2 mΩcm.
  • For rendering an electrically insulating ceramic electrically conductive it is known to admix to the insulating ceramic material particles of electrically conductive nitrides, carbides and/or borides ( WO 95/0443 , DE 101 41 660 A1 ).
  • US patent 5,750,958 relates to a ceramic heater to be used as ceramic glow plugs. The heater is composed of an insulating ceramic sintered body made of silicon nitride (Si3N4) and a heating element embedded in the insulating ceramic body. The heating element is made of an anorganic electrically conducting material, in admixture of a minor part of Si3N4.
  • For example, the heating element can be mainly made of a carbide or nitride of elements of groups 4a, 5a and/or 6a of the periodic system, such as WC, TiC or ZrB2. According to a preferred example the heating element comprises 65 to 95 weight% WC and 5 to 45 weight% Si3N4. The heating element is a printed structure of a thickness in the range of 2.3 to 150 µm and can be applied by a screen printing method or the like.
  • WO 97/31878 discloses the use of barium zirconate (BaZrO3) and strontium zirconate (SrZrO3) as a low reactive material for a crucible for melting superalloys. It is indicated, that the material becomes electrically conductive at high temperature, but is electrically insulating at ambient temperature. In view of the electrically conductivity at high temperatures it is suggested using the material as an additional heating element in the melting of the superalloys as soon as the operation temperature is sufficiently high so that the material becomes electrically conductive.
  • In view of the above it was the object of the present invention to provide a material to be used in electrical applications such as a heating element or ohmic resistor which is resistant to oxidation, can be operated even at very low voltage levels, can withstand high temperatures without damage, and allows a wide variation in design and shape.
  • The object of the present invention is solved by using oxide ceramic materials and metal ceramic compounds having superconducting properties or can be converted to superconducting materials in non-superconducting electrical applications.
  • According to the present invention the term "non-superconducting electrical application" is understood to mean normal conducting application above the critical temperature of the respective superconducting material, that is above the temperature at which the material becomes superconducting.
  • In particular, "non-superconducting electrical application" means an application requiring no cooling of the material as necessary in superconducting applications. Further, this term particularly means any electrical application for which conventionally a normal conducting material is used which has no superconducting potential.
  • Examples of non-superconducting electrical applications are the use as heating element, ohmic resistors, electrodes in electrical arc discharge and so on.
  • For the purpose of the present invention the oxide ceramic materials and metal ceramic materials as used in the present invention are also commonly referred to "material(s) of the present invention".
  • Oxide ceramic materials of the present invention are those known in the production of oxide ceramic high temperature superconductors selected from the group consisting of alkaline earth cuprates and rare earth alkaline cuprates. Typical examples comprise oxide ceramic high temperature superconductors based on Bi-Ae-Cu-Oy, (Bi, Pb)-Ae-Cu-Oy and Re-Ae-Cu-Oy.
  • In the above formulas Ae means at least one alkaline earth element, particularly Ba, Ca and/or Sr. Re means at least one rare earth element, particularly Y or a combination of two or more of the elements Y, La, Lu, Sc, Ce, Nd or Yb. In each of the above formulas, y represents the relative oxygen content of the particular oxide ceramic superconductor material or resulting from the specific nominal composition.
  • Examples for suitable oxide ceramic materials are those with a nominal composition of BSCCO-2212, BSCCO-2223, YBCO-123 and YBCO-221 wherein the numerical combinations 2212, 2223, 123 and 221 stand for the stoichiometric ratios of the respective elements and wherein part of Bi can be substituted by Pb.
  • Generally high temperature superconductor materials are understood to be materials with superconducting property at a critical temperature above the temperature of liquid nitrogen (about 77 K).
  • Apart from the high temperature superconductor materials superconductor materials with Tc below 77 K are suitable.
  • A superconducting oxide ceramic material suitable for the present invention are those known as iron pnictides, a new class of oxide ceramic superconductors reported, for example, by H. Hosono et al. in J. Am. Chem. Soc. 130, 3296 (2008). The iron pnictides have a general formular of Re'(O1-xFx)FeAs or (Re'1-yMy)OFeAs with Re' being one or more rare earth element of atomic number 57 to 71, in particular La, Ce, Pr, Nd, Sm and Gd and M being a metal.
  • The parent compound, LaOFeAs, is not superconducting, but upon replacing some of the oxygen by fluorine, the material becomes superconducting.
  • Apart from replacing minor part of oxygen by fluorine it has been shown that the material becomes superconducting on replacement of minor part of Re' by another metal, for example Sr, Th and so on.
  • The specific value of x and y depends on the particular compound.
  • Particular examples are (Gd,Th)OFeAs (Tc about 65 K), LaO1-xFxFeAs (Tc about 26 K), CeO1-xFxFeAs (Tc about 40 K) PrO1-xFxFeAs and NdO1-xFxFeAs (both Tc above 50 K).
  • A suitable metal ceramic compound is MgB2 which has also superconducting properties at a temperature of about 39 °K.
  • For the present invention it is not necessary that the oxide ceramic material or the metal ceramic compound already has superconducting properties. That is, the present invention also encompasses precursors of the respective superconducting material.
  • For example, for the present invention the precursors of oxide ceramic superconducting material such as mixtures of oxides that have the same nominal composition as the respective oxide ceramic superconducting material can be used, which can be transferred to the superconducting state by suitable treatment, such as heating.
  • It has been found that the materials of the present invention have a specific resistance at ambient temperature (20 °C) in a range of about 1 to 10 mΩcm. Thus, the specific resistance of these materials is significantly higher than that typically found for metals (about 0.01 to 0.2 mΩcm), but is by far less than that of conventional insulating ceramic materials being 108Ωcm and higher.
  • Due to this comparatively high specific resistance the materials of the present invention can be advantageously used in non-superconducting electrical application.
  • For example, due to the specific resistance even at very low voltage level of 40 V or less high temperatures can be obtained which are suitable for a heating element, but without damage of the material.
  • The material of the present invention can be easily obtained by, for example, admixing the respective oxides of the metal constituents or by any other process known in the production of a precursor material for the respective superconducting material.
  • The material of the present invention can be used in form of a thin film, a printed pattern or any massive or hollow shaped body, for example having an essentially quadrangular, polygonal, oval or round cross-section. Examples are plates, disks, rods or tubes.
  • Further, on demand, the materials of the present invention can be used in form of granules.
  • In the production of films and shaped bodies made from these materials and suitable in the electrical applications any process known for processing the respective materials can be used.
  • Pattern or thin films can be obtained, for example, by any printing method such as a screen printing method.
  • Shaped bodies can be obtained by these materials by using well established ceramic production processes. For examples, heating elements in form of tubes or plates can be obtained by simple casting or spin casting of these materials. A centrifugal melt casting process suitable for the present invention is disclosed in EP 0 462 409 B1 , which is incorporated herein by reference.
  • A heating element obtained by a melt cast process is advantageous over a heating element obtained by conventional sintering process in that the obtained body has a by far less porosity.
  • There is no particular restriction as to the shape or design to which the ceramic material used in the present invention can be processed. Thus the use of the ceramic material of the present invention offer a broad variability in electrical applications.
  • Due to its easy processability the material of the present invention can be suitably used in the production of heaters of large area.
  • The electrical resistance of the materials of the present invention can be easily adjusted to the specific requirements of a desired electrical application by varying the phase composition of the material by variation of processing parameters like temperature of atmosphere and/or by doping the oxide ceramic material or metal ceramic compounds with other chemical elements.
  • Suitable doping materials are those which can be homogenously mixed with respective superconducting material, for example with the respective melt of the superconducting material in case of melt casting, and which does not cause any mechanical defect in the superconducting layer or body subsequent to cooling. Preferred examples of such doping materials are metal oxides, or salts which are not readily soluble, e.g. strontium sulfate (SrSO4).
  • In particular, the material can be easily transformed by doping from a so called PTC resistor (positive temperature coefficient) as typically designed from metals, to a so called NTC resistor (negative temperature coefficient) as typically designed from semi-conductors. This allows easy design and modification in weight and size of a body or element made from the material of the present invention, for example an ohmic resistor for power applications.
  • Electrodes made of the material of the present invention can be advantageously used in deposition of thin layers by vaporization of the material by means of electric arc discharge.
  • To this, the electrodes formed from the material of the present invention are momentarily held in contact to each other and applying voltage to the electrodes. Then, the electrodes are separated thereby forming a stable electric arc.
  • Since both electrodes are made from the same material, contamination of the layer to be deposited by impurities is completely or at least almost completely avoided.
  • In particular, by electric arc discharge using electrodes made of the material of the present invention thin layers made of (high temperature) superconducting material can be deposited onto a suitably textured substrate, for example in the production of coated conductors. Generally, coated conductors are well known in the art. Typically, they are wires or tapes with superconductor properties composed at least of a substrate, optionally one or more buffer layers deposited onto the substrate and a thin layer of superconducting material deposited onto the buffer layer.
    • Example 1: heating system based on YBCO 123
  • An experimental device was assembled from a plate of polycrystalline YBCO 123 of about 40 cm2 and a thickness of 1.5 cm.
  • A current of about 44 A was conducted at a voltage of about 9 V. A homogeneous temperature of above 800 °C was reached for several hours without degradation of the material.
  • Production method of the shaped body made of YBCO 123:
    1. a) preparing powder of the oxides of the metal constituents, Y, Ba and Cu
    2. b) pressing powder to shaped body
    3. c) sintering green body at about 900 °C
    4. d) crystallizing sintered plate of YBCO 123 at about 1050 °C
    5. e) adjusting oxygen content by heating at about 600 °C in an oxygen atmosphere.
  • The obtained superconducting shaped body was provided with electrical contacts for supplying current.
    • Example 2: tube shaped heating element
  • A tube shaped heating element was manufactured from BSCCO 2212 material by a centrifugal melt casting process. The element worked without problems up to an operation temperature in air of above 500 °C.
  • Production method of shaped body made of BSCCO 2212:
    1. a) preparing powder of the oxides of the respective metal constituents Bi, Sr, Ca and Cu,
    2. b) melting powder at about 1100 °C and casting into a tube shape
    3. c) adjusting oxygen content at about 830 °C at air atmosphere.
  • The resulting superconducting shaped body was provided with electrical contacts for supplying current.

Claims (13)

  1. Use of an oxide ceramic material or of a metal ceramic compound which has superconducting properties or can be converted to a superconducting state in non-superconducting normal electrical applications.
  2. Use of a material according to claim 1,
    wherein the material has a specific resistance in a range of 1 to 10 mΩcm at 20 °C.
  3. Use of the material according to claim 1 or 2,
    wherein the material is selected from alkaline earth cuprates, rare earth alkaline cuprates, iron pnictides and magnesium diboride.
  4. Use of the material according to any of claims 1 to 3 in low voltage applications at a voltage of 40 V or less.
  5. Use of the material according to any of the claims 1 to 4 as a heating element, ohmic resistor or electrode suitable in electrical arc discharge.
  6. Use of the material according to any of the claims 1 to 5,
    wherein the material is in form of a thin film, solid shaped body or granulate.
  7. Use of the material according to claim 6,
    wherein the solid shaped body is a massive or hollow article having a quadrangular, polygonal, oval or round cross section.
  8. Use of the material according to claims 6 or 7,
    wherein the shaped body is obtained by a melt casting process.
  9. Heating element made of an oxide ceramic material or of a metal ceramic compound which has superconducting properties or can be converted to a superconducting state.
  10. Ohmic resistor made of an oxide ceramic material or of a metal ceramic compound which has superconducting properties or can be converted to a superconducting state.
  11. Heating element or ohmic resistor according to claims 9 or 10,
    wherein the material is selected from alkaline earth cuprates, rare earth alkaline cuprates, iron pnictides and magnisum diboride.
  12. Heating element or ohmic resistor according to any of the claims 9 to 11,
    wherein the material has a specific resistance in a range of 1 to 10 mΩcm at ambient temperature.
  13. Electrode suitable in electrical arc discharge made of a material referred to in any of claims 1 to 3.
EP09305525A 2009-06-10 2009-06-10 Use of oxide ceramic materials or metal ceramic compounds for electrical applications likes heaters Withdrawn EP2262346A1 (en)

Priority Applications (1)

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EP09305525A EP2262346A1 (en) 2009-06-10 2009-06-10 Use of oxide ceramic materials or metal ceramic compounds for electrical applications likes heaters

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EP2262346A1 true EP2262346A1 (en) 2010-12-15

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2544833C1 (en) * 2014-03-14 2015-03-20 Открытое акционерное общество "Восточный научно-исследовательский углехимический институт" (ОАО "ВУХИН") Method of producing carbon-containing electroconductive material
CN114937537A (en) * 2022-06-21 2022-08-23 西安西电高压电瓷有限责任公司 Carbon ceramic closing resistor and preparation process thereof

Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1282023A (en) * 1969-11-03 1972-07-19 Standard Telephones Cables Ltd Electrical resistor material
US5073537A (en) * 1990-02-06 1991-12-17 Eastman Kodak Company Electrically conductive article
EP0494128A1 (en) * 1991-01-03 1992-07-08 Pechiney Electrometallurgie Oxynitride based product for covering screened electrical resistors and for refractory application and method of making same
EP0462409B1 (en) 1990-06-18 1994-07-13 Hoechst Aktiengesellschaft Process for the production of tube shaped mouldings out of high temperature superconductor material and plant for carrying out this process
WO1995000443A1 (en) 1993-06-22 1995-01-05 Devoe Irving W Process for the desalinization of sea water and for obtaining the raw materials contained in sea water
WO1997031878A1 (en) 1996-02-28 1997-09-04 Universite De Geneve Ceramic member, method for producing such a member and use of such a member
US5750958A (en) 1993-09-20 1998-05-12 Kyocera Corporation Ceramic glow plug
US6291402B1 (en) * 1987-05-05 2001-09-18 Lucent Technologies Inc. Method of making a superconductive oxide body
DE10141660A1 (en) 2001-08-24 2003-03-06 Sintered Parts And Services Gm Ceramic composite body used in the production of bearing bushings, bearing shafts, nozzles, sliding bearings or sliding ring seals comprises an outer casing ceramic and a sintered material having electrical and/or mechanical properties
WO2005006455A1 (en) * 2003-07-04 2005-01-20 Rolls-Royce Plc A fault current limiter
US20050231202A1 (en) * 2002-05-07 2005-10-20 Hiroshi Morita Probe for NMR apparatus using magnesium diboride
EP1688514A1 (en) * 2003-11-20 2006-08-09 Denki Kagaku Kogyo Kabushiki Kaisha Metal vaporizing heating element and metal vaporizing method
US20070194870A1 (en) * 2006-02-20 2007-08-23 Hitachi, Ltd. Permanent current switch

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1282023A (en) * 1969-11-03 1972-07-19 Standard Telephones Cables Ltd Electrical resistor material
US6291402B1 (en) * 1987-05-05 2001-09-18 Lucent Technologies Inc. Method of making a superconductive oxide body
US5073537A (en) * 1990-02-06 1991-12-17 Eastman Kodak Company Electrically conductive article
EP0462409B1 (en) 1990-06-18 1994-07-13 Hoechst Aktiengesellschaft Process for the production of tube shaped mouldings out of high temperature superconductor material and plant for carrying out this process
EP0494128A1 (en) * 1991-01-03 1992-07-08 Pechiney Electrometallurgie Oxynitride based product for covering screened electrical resistors and for refractory application and method of making same
WO1995000443A1 (en) 1993-06-22 1995-01-05 Devoe Irving W Process for the desalinization of sea water and for obtaining the raw materials contained in sea water
US5750958A (en) 1993-09-20 1998-05-12 Kyocera Corporation Ceramic glow plug
WO1997031878A1 (en) 1996-02-28 1997-09-04 Universite De Geneve Ceramic member, method for producing such a member and use of such a member
DE10141660A1 (en) 2001-08-24 2003-03-06 Sintered Parts And Services Gm Ceramic composite body used in the production of bearing bushings, bearing shafts, nozzles, sliding bearings or sliding ring seals comprises an outer casing ceramic and a sintered material having electrical and/or mechanical properties
US20050231202A1 (en) * 2002-05-07 2005-10-20 Hiroshi Morita Probe for NMR apparatus using magnesium diboride
WO2005006455A1 (en) * 2003-07-04 2005-01-20 Rolls-Royce Plc A fault current limiter
EP1688514A1 (en) * 2003-11-20 2006-08-09 Denki Kagaku Kogyo Kabushiki Kaisha Metal vaporizing heating element and metal vaporizing method
US20070194870A1 (en) * 2006-02-20 2007-08-23 Hitachi, Ltd. Permanent current switch

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
H. HOSONO ET AL., J. AM. CHEM. SOC., vol. 130, 2008, pages 3296
MÜNSTER A ET AL.: "Uber einige elektrische Eigenschaften von Titannitrid und Titancarbid", ZEITSCHRIFT FUR PHYSI, vol. 144, 1956, pages 139 - 151

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2544833C1 (en) * 2014-03-14 2015-03-20 Открытое акционерное общество "Восточный научно-исследовательский углехимический институт" (ОАО "ВУХИН") Method of producing carbon-containing electroconductive material
CN114937537A (en) * 2022-06-21 2022-08-23 西安西电高压电瓷有限责任公司 Carbon ceramic closing resistor and preparation process thereof
CN114937537B (en) * 2022-06-21 2023-12-19 西安西电高压电瓷有限责任公司 Carbon ceramic closing resistor and preparation process

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