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WO1993005520A1 - Composants electriques isoles par un spinelle et procede de fabrication de ceux-ci - Google Patents

Composants electriques isoles par un spinelle et procede de fabrication de ceux-ci Download PDF

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Publication number
WO1993005520A1
WO1993005520A1 PCT/US1992/007456 US9207456W WO9305520A1 WO 1993005520 A1 WO1993005520 A1 WO 1993005520A1 US 9207456 W US9207456 W US 9207456W WO 9305520 A1 WO9305520 A1 WO 9305520A1
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WO
WIPO (PCT)
Prior art keywords
spinel
set forth
paste
insulation
ceramic
Prior art date
Application number
PCT/US1992/007456
Other languages
English (en)
Inventor
William J. Koch
Collins P. Cannon
Original Assignee
American Technology, Inc.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by American Technology, Inc. filed Critical American Technology, Inc.
Publication of WO1993005520A1 publication Critical patent/WO1993005520A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01K—MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR
    • G01K7/00—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements
    • G01K7/02—Measuring temperature based on the use of electric or magnetic elements directly sensitive to heat ; Power supply therefor, e.g. using thermoelectric elements using thermoelectric elements, e.g. thermocouples
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/44—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminates
    • C04B35/443—Magnesium aluminate spinel
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/10—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances metallic oxides
    • H01B3/105—Wires with oxides
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B3/00—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties
    • H01B3/02—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances
    • H01B3/12—Insulators or insulating bodies characterised by the insulating materials; Selection of materials for their insulating or dielectric properties mainly consisting of inorganic substances ceramics
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B7/00—Insulated conductors or cables characterised by their form
    • H01B7/16—Rigid-tube cables

Definitions

  • This invention is generally directed to mineral insulated electrical components, such as cables and sensors, and, more particularly, to spinel insulation used in such cables and sensors, methods for producing the spinel insulation, a spinel preform, and a spinel insulated cable.
  • Mineral insulation is often used in the fabrication of electrical components, such as sensors and cables. Mineral insulation is known to provide good resistance to environmental stresses, such as thermal and nuclear radiation. Heretofore, significant shortcomings have existed in the use of conventional mineral insulation. These shortcomings are evident in the problems associated with mineral insulated cables, but exist in many other types of electrical components, such as sensors.
  • a hard cable typically includes an inner conductive wire surrounded by a mineral insulator, such as a ceramic, and placed within a metallic jacket.
  • the mineral insulator resists the effects of environmental invasive stress, such as radiation, owing to its crystal structure.
  • Mineral insulation for cables has typically been formed from ceramics, such as magnesium oxide (MgO) or aluminum oxide (A1 2 0 3 ) . Both of these ceramics, and especially magnesium oxide, have very good insulation resistance (if pure) at temperatures to 800'C. Above this temperature, magnesium oxide tends to react with the jacket and/or the internal wire and will form white smoke and dissociate in a reducing atmosphere.
  • Aluminum oxide does not typically have resistivity values as high as those of magnesium oxide at elevated temperatures. Further, neither of these materials are effective insulators over time in a fast neutron radiation environment, due to a complete break-down or collapse of their crystal structure.
  • magnesium oxide has a tendency to react with the jacket and internal wire; however, when heated, this problem is exacerbated, as the heat partially reduces the magnesium oxide, and the resulting magnesia is highly reactive with the internal wire and jacket.
  • Some relief has been obtained by venting the jacket of the cable to expose the magnesium oxide to the external atmosphere. This venting has a tendency to keep the magnesium oxide in its oxide form, and thereby reduce reaction with the jacket and internal wire.
  • magnesium oxide has a strong tendency to hydrate or absorb water, which necessarily results in corrosion of the jacket and internal wire.
  • venting the jacket tends to limit reduction of the magnesium oxide, and reduce reaction between the magnesium oxide, jacket, and internal wire, it also induces a different type of reactive influence, corrosion.
  • hydration reduces the effectiveness of the magnesium oxide as an electrical insulator, and may lead to voltage breakdown between the jacket and wire. These areas of voltage breakdown cause failure of the cable.
  • the present invention is directed to overcoming or minimizing one or more of the problems discussed above.
  • ceramic insulation in a mineral insulated electrical component is provided.
  • the insulation is comprised of spinel.
  • a paste suitable for firing into a ceramic for use as insulation in a mineral insulated electrical component is provided.
  • the paste is formed from spinel powder and a binder solution.
  • a method for forming a ceramic to be used as insulation in a mineral insulated electrical component includes the steps of: preparing a binder solution; preparing a spinel powder; combining the spinel powder and binder solution into a paste; and firing the paste.
  • Fig. 1 illustrates a perspective cut-away view of a coaxial mineral insulated cable
  • Fig. 2 illustrates a perspective cut-away view of a triaxial mineral insulated cable
  • Fig. 3 illustrates a cross-sectional view of a coaxial mineral insulated thermocouple.
  • a ceramic insulation 10 a center conductor electrical wire 12, and a metallic sheath 16, which, when assembled, form a mineral insulated or hard cable 18.
  • the metallic sheath 16 is preferably formed from a nickel iron chrome alloy, or a more refractory metal, if required.
  • the electrical wire 12, is formed from any suitable conductive material, however, copper is preferred.
  • the ceramic preform 10 is preferably formed from a ceramic mixture having a ratio of 28.2% magnesium oxide to 71.8% aluminum oxide by weight, and being fired into new compound, spinel (MgAl 2 0 4 ) .
  • the hard cable 18 represents a first embodiment of the instant invention, with other embodiments, such as a sensor, illustrated and discussed subsequently herein.
  • the ceramic insulation 10 can be deposited in the metallic sheath 16 using a variety of processes without departing from the spirit and scope of the instant invention. Two preferred processes are described subsequently herein.
  • the first process involves firing the spinel into ceramic preforms and threading the preforms onto the wire 12.
  • the insulation 10 can also be placed in the sheath 16 in powdered or granulated form, using conventional loading, vibrating, and ramming techniques to ensure that voids are not created.
  • the wire 12 is manually threaded through a series of relatively short preforms 10 (i.e., typically two to four inches each) until a desired length is reached (i.e., typically forty feet) . Thereafter, the wire 12 and preforms 10 are inserted into the sheath 16 to form the hard cable 18.
  • a series of relatively short preforms 10 i.e., typically two to four inches each
  • a desired length i.e., typically forty feet
  • the assembled hard cable 18 is passed through conventional metallic drawing dies.
  • the drawing dies forcibly reduce the diameter of the sheath 16, and thereby lengthen the cable by a small amount.
  • the cable 18 is gradually reduced in diameter and increased in length until a desired diameter and/or length is reached. It is preferable to heat treat (anneal) the cable between successive draws to remove work hardening from the metal sheath 16.
  • the ceramic preforms 10 positioned within the cable 18 are relatively hard, but are crushed during the drawing or swaging operation. This crushing action, however, advantageously allows the ceramic to fill any voids within the cable 18 and thereby improve the cable's electrical properties.
  • Thermocouples and small diameter mineral insulated electric cables are commonly constructed using the above- described ceramic preform technique.
  • Mineral insulated heaters, thermocouples, and many types of electrical cables are, however, commonly constructed using a powder fill method, as described below.
  • the spinel insulation 10 is reduced to or obtained in a powdered or granulated form and then loaded into the sheath 16 using conventional techniques. These conventional techniques are in common usage to produce MgO type insulated cables, and, therefore, need not be discussed in detail herein.
  • the powdered spinel is typically placed in the sheath 16 about the wire 12 by a mechanism such as a funnel loading or screw type auger as the sheath 16 is vibrated. Vibration aids in compacting the powder and prevents formation of voids in the insulation 10. Ordinarily, the powder is also tamped into the sheath during this process.
  • the instant invention finds beneficial application in multi-conductor cables, i.e. cables where the number of electrical conductor wires present within the interior of the ceramic insulation varies from two to upwards of 200. In cable geometries of this type, it is generally preferable to position the wires so that insulation thickness between adjacent wires and between wires and the sheath are equal.
  • Triaxial-type hard cables are substantially similar to that shown in Fig. 1, but include an additional metallic sheath 20 positioned between the wire 12, and the sheath 16 (see Fig. 2). Insulation 22, 24 is provided between the sheaths 16, 20 and also between the additional sheath 20 and the wire 12.
  • the insulation 24 placed between the wire 12 and additional sheath 20 is preferably spinel, whereas the insulation 22 placed between the sheaths can take any of a variety of forms, including, but not limited to, mineral insulators, such as spinel.
  • Fig. 3 illustrates a slightly different use of the spinel insulator 10 from the above-described use in cables. That is, the insulator 10 is useful in not only cables, but also in electrical sensors, which may be attached to the cable 18. Hardened sensors are useful for the same reasons that hardened cables are useful in environmentally stressful conditions. In fact, attaching a non-hardened sensor to a hardened cable may not extend the useful life of the system, since the sensor remains susceptible to early failure.
  • thermocouples While many types of sensors are envisioned as being benefited by the use of spinel insulation, its application to thermocouples is illustrative of the application to sensors in general.
  • Fig. 3 illustrates a cross sectional view of a thermocouple 50 formed from an outer sheath 52, a pair of internal dissimilar wires 54, 56, and a mineral insulator 58.
  • thermocouple 50 The methods useable for constructing the thermocouple 50 are substantially identical to those discussed above in conjunction with the cable 18. Further, the methods described below for constructing the spinel insulation are equally useful in constructing the mineral insulator 58.
  • MgAl 2 0 4 Spinel (MgAl 2 0 4 ) formed from a one to one molar ratio of magnesium oxide (MgO) and aluminum oxide (A1 2 0 3 ) exhibits superior resistance to the effects of fast neutron radiation. It also exhibits superior stability when subjected to temperature extremes, which are a common projection for many accident scenarios, such as might occur in a nuclear reactor. MgAl 2 0 4 overcomes the limitations inherent when MgO and A1 2 0 3 are used alone as the insulation in a hard cable.
  • the elementary cell of spinel contains eight "molecules" of MgAl 2 0 4 , or eight magnesium ions, sixteen aluminum ions, and thirty-two oxygen ions, for a total of fifty-six ions. Since the structure of MgAl 2 0 4 is determined by the space configuration of comparatively large oxygen ions, between which small tri and bivalent cations are inserted, a material exchange and even a certain disorder of the cations is possible due to neutron radiation, without causing a basic change in the lattice.
  • MgAl 2 0 4 because of its stoichiometry and extremely stable crystal structure, provides superior resistance to degradation of its dielectric and physical properties under the separate or combined environmental stresses of elevated temperature and nuclear radiation. MgAl 2 0 4 does not, therefore, react with metals, as do MgO and Al 2 ⁇ 3 .
  • the method for fabricating the spinel preform begins with obtaining starting materials that are in a usable condition.
  • the need to place the starting material used to fabricate the preform in a "desired" stoichiometric state is of primary concern.
  • a subsequent analysis of the X-ray diffraction pattern is then performed to establish the "as-received" stoichiometric state and to assure that complete reaction of all alumina or magnesia grains has been achieved to form the approximately 1:1 molar Mg0-Al 2 0 3 compound.
  • Another obstacle to the formation of a satisfactory preform is the control of trace contaminants. Contaminants in the spinel powder, or their introduction during the fabrication process to form the crushable spinel preform, can disturb the stoichiometric state achieved in the final preform, and thereby sharply curtail the ability of the final spinel insulated cable to withstand radiation and temperature stresses.
  • the fabrication process described herein illustrates how this is accomplished.
  • a binder solution is combined with a MgAl 2 0 4 homogenous powder to form a paste that is suitable for extruding and will substantially maintain the extruded shape. Accordingly, a first step involves the preparation of the binder solution.
  • the solution When the solution reaches 85"C, it should be removed from the heat, and 567.5 grams of Methocel #A4C should be stirred into the solution slowly. After approximately two minutes of stirring the solution appears milky in color. Thereafter, 1800 grams of triple distilled water are stirred into the milky solution.
  • the triple distilled water Preferably, the triple distilled water should be at approximately room temperature. This entire solution is preferably covered and aged overnight. Shelf life of the solution is estimated to be approximately six to eight weeks if kept cool (i.e., 7 to 10"C) .
  • a homogeneous sample is taken from the powder using a "thief" tube or similar sampling device.
  • the sample is then X-rayed using X-ray diffraction to determine if all of the powder is in an approximately 1:1 molar ratio of A1 2 0 3 to MgO to form the required MgAl 2 0 4 spinel compound.
  • the powder is recalcined by placing it in a magnesium oxide crucible and heating the powder to a minimum of 1200°C in an air atmosphere in an electrically heated type firing furnace.
  • the 1200*C temperature is maintained for a four hour holding period. Thereafter, the furnace is turned off and the recalcined powder is allowed to cool in the furnace.
  • the recalcined powder is then broken up using an alumina mortar and pestle and ball milled using a conventional polypropylene lined ball mill and alumina balls or cylinders in dehydrated methanol.
  • the recalcined powder is ball milled to a particle size of 1 to 10 microns.
  • the powder After air drying at 125°C maximum temperature, the powder is again examined by X-ray diffraction to assure an approximately 1:1 molar ratio of MgO to A1 2 0 3 , and that all of the material has been reacted.
  • the binder solution and pure MgAl 2 0 4 ceramic powder prepared are combined to form an extrusion paste.
  • Approximately 1000 grams of the MgAl 2 0 4 powder and 310 grams of the binder solution are added to a sigma blade type stainless steel mixer, such as is available from Paul O. Abbe, Inc., of Little Falls, New Jersey.
  • the total working chamber, including all moving parts, of the mixer should be coated with titanium nitride.
  • a titanium nitride coated cover plate of the mixer should be locked in place to prevent spillage.
  • the mixer is first operated until the contents appear uniform (approximately three minutes) . At that time, 40 grams of a mixture of a 10% binder solution dissolved in 90% triple distilled water is added to the contents of the mixer.
  • the resulting paste should be sufficiently stiff to have no deformation of the hole or outer diameter of the preform 10 after extrusion or drying.
  • the batch is divided in half, and each half batch is mixed for approximately three to four minutes. Each half batch is then placed in a plastic bag and aged from an approximate minimum time of ten hours at a temperature of 7 to 10°C.
  • the moisture content of the paste should be approximately 27+1 percent.
  • the moisture content can be determined either by using a weight loss method or by using a moisture balance, such as a Mettler LP16-M Moisture Determination System available from
  • the weight loss method of determining moisture content involves accurately weighing the paste before and after drying at about 100°C for about four hours. The difference in weight corresponds to the amount of moisture lost therefrom.
  • the paste should preferably be extruded within one week after preparation.
  • the paste should be kneaded by hand on a clean plexiglass sheet for approximately two minutes to give it uniform plasticity and to form it into a shape for loading into an extruder.
  • the extrusion process begins using r for example, a 40-ton extruder, such as is available from Loomis Products, Co. of Levittown, Pennsylvania.
  • the extruder has an extrusion chamber inner lining and ram plunger end plate of tungsten carbide.
  • the extruder includes a pin used to form the opening in the preform 10 so that the wire 12 may be threaded therethrough.
  • This pin is adjustable and should preferably be properly positioned or centered prior to actually extruding the paste.
  • Extrusion pressure should be held at about three to four tons, as registered on the pressure gauge.
  • the resulting extrusions are preferably placed on 1/4" wide V shaped grooves in a plaster board (6" wide x 30" long x 3/4" total thickness) that has been dusted previously with GP-38 graphite powder, available from Union Carbide Coatings Corp. of Danbury, Connecticut.
  • the damp extrusions should preferably be placed in a drying chamber.
  • the extrusions are preferably dried on the graphite dusted plaster boards at approximately 100 * F maximum in a closed chamber for a minimum of approximately 25 hours. This drying is supplemented by overnight drying at 125 to 150 ⁇ C in an air circulating dryer.
  • the extrusions After drying, the extrusions have a wood-like consistency and can be readily cut to a desired length for firing.
  • the extrusions can be cut to a desired firing tile length using a back and top block, straight edge, and a safety-type stainless steel razor blade or Ex-acto * knife.
  • the cut extrusions should be loaded onto a mullite grain bonded hi-alumina type V-grooved setter tray, such as is available from Applied Ceramics, Inc., of Atlanta, Georgia, as part number TAC 218.
  • the V- grooves should be filled to approximately 1/8" over their depth with a plurality of the extrusions stacked therein.
  • the loaded hi-alumina grooved setter trays are stacked four high and two wide into a periodic furnace, such as a 3000 series furnace with Kanthal Super 33 heating elements, available from CM Furnaces, Inc. of Bloomfield, N.J.
  • a periodic furnace such as a 3000 series furnace with Kanthal Super 33 heating elements, available from CM Furnaces, Inc. of Bloomfield, N.J.
  • the spinel rods are fired in an air atmosphere on the mullite bonded alumina refractory "V" trays.
  • the furnace is heated to 400°C over a three hour period and held at that temperature for one hour. Thereafter, the temperature of the furnace is first raised to 1275°C at a rate of 150 ⁇ C per hour, and then at 100°C per hour to a peak temperature of 1400°C. This peak temperature is held for two hours, and then the heating elements of the furnace are turned off and the parts are allowed to cool overnight (minimum) in the closed furnace.
  • the spinel preforms 10 are now ready to be cut to specified length, usually two inches.
  • the preforms 10 are preferably cut to a flat end cut using a back and top block straight edge and a four inch diameter diamond impregnated 1/32" wide cutting wheel.
  • the modulus of rupture (MOR) is measured using a Chatillon model DFGHS- 100 digital compressive force gauge on a model LTCM-4 mechanical test stand.
  • the test stand is preferably equipped with a controlled motorized lifting table and a tungsten carbide base block having its tungsten carbide chisel edge tip positioned on the bottom of the digital force gauge.
  • the MOR of the preforms 10 should be approximately 2000 + 200 PSI.
  • the outer diameter of the preforms 10 should be measured with, for example, a spring loaded electronic digital read-out micrometer.
  • the outer diameter tolerance of the preforms 10 is approximately +1.6% for an outer diameter of about 0.200 inches.
  • the inner diameter of the openings should be measured using, for example, spring steel gauge pins accurate to + 0.0001 inch.
  • the gauge pins are available in intervals of 0.001 inch.
  • camber is measured and preferably should be within the following tolerance:
  • Typical camber 0.005 inch/inch or mm/mm;
  • the specific method described above results in a preform 10 that is spinel (MgAl 2 0 4 ) of a substantially 1:1 molar ratio. In certain applications, however, it is preferable that a slight excess of MgO or A1 2 0 3 be present in the spinel compound.
  • the instant invention also finds beneficial applications in other swageable components or internal heater or thermocouple parts, such as spacers, inserts, mandrels, end seal inserts, and other internal parts used in cable and component design.
  • the ceramic insulator 10 has been described above as being composed exclusively of spinel. However, it is envisioned that the advantages of spinel insulation may be obtained through the use of a mixture that is comprised only partially of spinel. That is, spinel may be combined with other materials to produce a ceramic that exhibits comparable qualities to that of spinel alone.
  • refractory dielectrics are expected to work well in combination with spinel.
  • the term refractory dielectric is generally defined as a high temperature (or heat resistant) electrical insulator, and generally includes mineral compounds such as oxides, nitrides, etc.
  • silica Si0 2
  • kaolin pyrophyllite
  • bentonite talc
  • dielectric insulator material such as Ce ⁇ 2 , Li 2 0, Li 2 0 3 , MgO, A1 2 0 3 , Sm 2 0 3 , Ti0 2 , TiN, Si 2 N 4 , BaTi0 2 , Y 2 0 3 , MgAl 2 0 4 , and the like.
  • the refractory dielectrics have dielectric properties that approximates that of spinel, and, therefore, do not reduce the desirable electrical properties of spinel. That is, a spinel-refractory dielectric cable will retain, or at least approximate, the electrical performance of spinel alone.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Inorganic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Compositions Of Oxide Ceramics (AREA)

Abstract

On décrit un composant électrique isolé par un minéral, tel qu'un câble (18) ou capteur, possédant un conducteur central (12), une gaine métallique (16), et une isolation céramique, placée entre ces deux éléments, formée à partir du spinelle (MgAl2O4). Le composant isolé par le spinelle possède une haute résistance aux contraintes dues à l'environnement, telles que température élevée, pression, rayonnement neutronique dur à long terme, et milieux chimiques corrosifs.
PCT/US1992/007456 1991-09-09 1992-09-01 Composants electriques isoles par un spinelle et procede de fabrication de ceux-ci WO1993005520A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US75661091A 1991-09-09 1991-09-09
US756,610 1991-09-09
US91116492A 1992-07-09 1992-07-09
US911,164 1992-07-09

Publications (1)

Publication Number Publication Date
WO1993005520A1 true WO1993005520A1 (fr) 1993-03-18

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AU (1) AU2582292A (fr)
WO (1) WO1993005520A1 (fr)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001037288A1 (fr) * 1999-11-16 2001-05-25 Abb Research Ltd. Dispositif d'isolation electrique d'un element haute tension
US6759592B1 (en) * 2001-02-06 2004-07-06 Tyco Thermal Control Uk Limited Kaolin additive in mineral insulated metal sheathed cables
EP2030958A1 (fr) * 2007-08-27 2009-03-04 Rohm and Haas Electronic Materials LLC Spinelles d'aluminate de magnésium monolithiques et polycristallins
US20130029245A1 (en) * 2011-07-25 2013-01-31 Bloom Energy Corporation Measurement device for measuring voltages along a linear array of voltage sources
CN106898413A (zh) * 2015-12-18 2017-06-27 核工业西南物理研究院 基于镁铝尖晶石绝缘的抗辐照复合电缆
WO2017185345A1 (fr) * 2016-04-29 2017-11-02 深圳顺络电子股份有限公司 Fil composite et son procédé de préparation, et procédé de préparation de bobine d'induction d'alimentation
CN109734424A (zh) * 2019-02-26 2019-05-10 湖北宝上电缆有限公司 一种用于防火电缆的柔性保湿耐火材料及其制备方法
EP3764372A1 (fr) * 2019-07-12 2021-01-13 Nexans Câble comprenant une couche résistante au feu
EP3764373A1 (fr) * 2019-07-12 2021-01-13 Nexans Câble comprenant une couche céramique résistante au feu

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE839664C (de) * 1948-10-02 1952-05-23 Siemens Ag Verfahren zur Herstellung elektrischer Leitungen mit mineralischer Isolierung
US4200077A (en) * 1977-10-15 1980-04-29 Robert Bosch Gmbh Glow plug structure
JPS60214295A (ja) * 1984-04-11 1985-10-26 株式会社東芝 原子炉用計測装置
WO1990014671A1 (fr) * 1989-05-17 1990-11-29 Metal Manufactures Limited Fabrication de cables a gaine metallique et a isolation en matiere minerale

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE839664C (de) * 1948-10-02 1952-05-23 Siemens Ag Verfahren zur Herstellung elektrischer Leitungen mit mineralischer Isolierung
US4200077A (en) * 1977-10-15 1980-04-29 Robert Bosch Gmbh Glow plug structure
JPS60214295A (ja) * 1984-04-11 1985-10-26 株式会社東芝 原子炉用計測装置
WO1990014671A1 (fr) * 1989-05-17 1990-11-29 Metal Manufactures Limited Fabrication de cables a gaine metallique et a isolation en matiere minerale

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2001037288A1 (fr) * 1999-11-16 2001-05-25 Abb Research Ltd. Dispositif d'isolation electrique d'un element haute tension
US6759592B1 (en) * 2001-02-06 2004-07-06 Tyco Thermal Control Uk Limited Kaolin additive in mineral insulated metal sheathed cables
US9200366B2 (en) 2007-08-27 2015-12-01 Rohm And Haas Electronic Materials Llc Method of making polycrystalline monolithic magnesium aluminate spinels
JP2009107917A (ja) * 2007-08-27 2009-05-21 Rohm & Haas Electronic Materials Llc 多結晶性モノリシックアルミン酸マグネシウムスピネル
US8142913B2 (en) 2007-08-27 2012-03-27 Rohm And Haas Electronic Materials Korea Ltd. Polycrystalline monolithic magnesium aluminate spinels
EP2030958A1 (fr) * 2007-08-27 2009-03-04 Rohm and Haas Electronic Materials LLC Spinelles d'aluminate de magnésium monolithiques et polycristallins
US20130029245A1 (en) * 2011-07-25 2013-01-31 Bloom Energy Corporation Measurement device for measuring voltages along a linear array of voltage sources
US8993191B2 (en) * 2011-07-25 2015-03-31 Bloom Energy Corporation Measurement device for measuring voltages along a linear array of voltage sources
US20150162631A1 (en) * 2011-07-25 2015-06-11 Bloom Energy Corporation Measurement device for measuring voltages along a linear array of voltage sources
US9647283B2 (en) * 2011-07-25 2017-05-09 Bloom Energy Corporation Measurement device for measuring voltages along a linear array of voltage sources
CN106898413A (zh) * 2015-12-18 2017-06-27 核工业西南物理研究院 基于镁铝尖晶石绝缘的抗辐照复合电缆
WO2017185345A1 (fr) * 2016-04-29 2017-11-02 深圳顺络电子股份有限公司 Fil composite et son procédé de préparation, et procédé de préparation de bobine d'induction d'alimentation
US10867748B2 (en) 2016-04-29 2020-12-15 Shenzhen Sunlord Electronics Co., Ltd. Method for preparing a composite wire and a power inductor
CN109734424A (zh) * 2019-02-26 2019-05-10 湖北宝上电缆有限公司 一种用于防火电缆的柔性保湿耐火材料及其制备方法
EP3764372A1 (fr) * 2019-07-12 2021-01-13 Nexans Câble comprenant une couche résistante au feu
EP3764373A1 (fr) * 2019-07-12 2021-01-13 Nexans Câble comprenant une couche céramique résistante au feu
FR3098635A1 (fr) * 2019-07-12 2021-01-15 Nexans câble comprenant une couche céramique résistante au feu
FR3098636A1 (fr) * 2019-07-12 2021-01-15 Nexans Câble comprenant une couche résistante au feu
US11810695B2 (en) 2019-07-12 2023-11-07 Nexans Cable comprising a fire-resistant ceramic layer

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