US3538231A - Oxidation resistant high temperature structures - Google Patents

Oxidation resistant high temperature structures Download PDF

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US3538231A
US3538231A US810318A US3538231DA US3538231A US 3538231 A US3538231 A US 3538231A US 810318 A US810318 A US 810318A US 3538231D A US3538231D A US 3538231DA US 3538231 A US3538231 A US 3538231A
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coating
tungsten
core member
heating element
alloy
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Terry F Newkirk
Marc S Newkirk
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INTERN MATERIALS
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
    • H01B1/00—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors
    • 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
    • H05B3/02—Details
    • H05B3/06—Heater elements structurally combined with coupling elements or holders
    • 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—Heating elements characterised by the composition or nature of the materials or by the arrangement of the conductor
    • H05B3/12—Heating 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
    • 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
    • H05B3/62—Heating elements specially adapted for furnaces
    • H05B3/64—Heating elements specially adapted for furnaces using ribbon, rod, or wire heater
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/923—Physical dimension
    • Y10S428/924—Composite
    • Y10S428/926—Thickness of individual layer specified
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9335—Product by special process
    • Y10S428/937—Sprayed metal
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S428/00—Stock material or miscellaneous articles
    • Y10S428/922—Static electricity metal bleed-off metallic stock
    • Y10S428/9335—Product by special process
    • Y10S428/939—Molten or fused coating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12229—Intermediate article [e.g., blank, etc.]
    • Y10T428/12271—Intermediate article [e.g., blank, etc.] having discrete fastener, marginal fastening, taper, or end structure
    • Y10T428/12278—Same structure at both ends of plural taper
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12535—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.] with additional, spatially distinct nonmetal component
    • Y10T428/12625—Free carbon containing component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12708—Sn-base component
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/12—All metal or with adjacent metals
    • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
    • Y10T428/12736—Al-base component
    • Y10T428/12743—Next to refractory [Group IVB, VB, or VIB] metal-base component

Definitions

  • a structure such as a crucible or heating element which operates at very high temperatures in air without atmospheric corrosion has a core member made of tungsten, graphite, carbon or molybdenum.
  • a protective coating covers the core member and is composed of aluminum, preferably also tungsten and a low-melting, nonreactive metal from the group consisting of indium, tin, and gallium.
  • the coating remains in a partially liquid state forming a continuous protective film on the core member for an extended period.
  • This invention relates to structures which are capable of operating at very high temperatures without degradation due to oxidation. While we are concerned here specifically with high temperature electrical heating elements, the invention has application also in connection with crucibles, heat shields and linings, furnace components, heated filaments and other such structures which encounter very high temperatures in normal use.
  • heating elements are made of tungsten, carbon, graphite, molybdenum and other such materials which are able to withstand relatively high temperatures.
  • these materials deteriorate very rapidly due to oxidation.
  • the prior elements burn out almost immediately.
  • these elements deteriorate, although at a slower pace, so that their heat outputs vary and they still have a relatively short life.
  • the elements are usually operated in an inert atmosphere.
  • this requires that they be housed in an airtight enclosure which has to be purged of air or charged with an inert gas each time work is placed in the enclosure. This, of course, makes the overall unit relatively large and heavy, as well as expensive.
  • Heating elements made of other materials do exist which can be operated in air for varying periods of time at very high temperatures.
  • they have other disadvantages which limit their application.
  • structures made of some platinum alloys can operate at temperatures on the order of l600l700 C.
  • they are expensive, and their useful lives at these temperatures are quite short.
  • a 0.20 inch diameter platinum rhodium alloy element operated at a furnace temperature of 1650 C. will burn out after only 5 or 6 hours. If the temperature is reduced to 1600 C., its life span is still only a day or two.
  • this type of element must be very small and be operated in a small furnace, i.e. a inch diameter tube, in order to develop these high temperatures without prohibitive cost. Therefore, the amount of work that can be heated by it at any one time is very small.
  • Silicon carbide rods are capable of operating at temperatures as high as 1700-1750 C. Here again, however, their useful lives are quite short. In addition, the silicon carbide material is quite brittle and has a low tensile strength. Therefore, the element as a whole is quite fragile. Another disadvantage of the silicon carbide rods is that, at high temperatures, they have a very low watt density with the result that it takes a relatively long time for the heating elements to reach their operating temperatures.
  • Heating elements constructed of other materials have been proposed. However, invariably they are deficient in one or more of the respects of high cost, fragility and short life.
  • this invention aims to provide a structure which is capable of operating at very high temperatures in air with minimal atmospheric corrosion.
  • Another object of the invention is to provide an improved electrical heating element which can operate at these high temperatures for a relatively long period without failure.
  • a further object of the invention is to provide an improved electrical heating element which can withstand repeated temperature cyclings over a relatively wide temperature range.
  • Another object is to provide a high temperature heating element having selected reproductible heating characteristics.
  • Yet another object of the invention is to provide a high temperature heating element which is supported only at its ends, yet which does not sag in use.
  • Still another object of the invention is to provide an improved high temperature electric furnace using one or more of these heating elements.
  • our improved high temperature structure comprises a core member made of tungsten, graphite, carbon, molybdenum or combinations of these refractory materials.
  • a protective alloy coating covers the core member and is comprised of aluminum, preferably also tungsten, and a low-melting, nonreactive metal from the group consisting of indium, tin, and gallium. The preferred compositions of the alloy coatings will be described in more detail later.
  • the alloy coating forms a solid sheath around the core member.
  • the coating is maintained in a partially liquid state so that it forms a continuous protective film on the core member which isolates the latter from the air and thereby protects it from oxidation and other atmospheric corrosion. Also, for this reason, the coating is able to tolerate the expansion and contraction of the core member during temperature changes.
  • the aluminum component of the coating provides a protective oxide film on the surface of the element.
  • the indium, tin or gallium form a low melting fluid at the operating temperature which is essentially nonreactive with the underlying core material and which enables the aluminum oxide to remain fiowable on the surface of the core member so as to preserve the continuity of the coating.
  • the tungsten is desirable because it lowers the solubility of the coating for the core material and minimizes attack on it. It also increases the viscosity of the alloy so that a coating of optimum thickness can be applied to the core member.
  • Heating elements made in accordance with this invention are able to operate in air at temperatures as high as 1900 C. and more for relatively long periods without failure. This is in sharp contrast to uncoated elements having the same core material which fail substantially immediately (i.e. within 1-3 seconds). Moreover, the elements can be recycled many times between these high temperatures and room temperature without any material adverse affect. Also, the elements are structurally relatively strong and durable and have a minimum tendency to sag. Therefore, they can be supported solely at their ends. Yet, with all of these advantages, the elements are still relatively easy and inexpensive to make compared to those prior conventional ones which are able to withstand these very high temperatures. Consequently, a relatively large volume, high temperature furnace can be constructed using a number of these elements without the cost of the furnace becoming excessively high.
  • FIG. 1 is an isometric view of a high temperature electric heating unit made in accordance with this in- 'vention
  • FIG. 2 is a triangular compositional diagram of the coating utilized in the practice of the present invention.
  • a FIG. 3 is an isometric view of another embodiment of our heating element; and
  • FIG. 4 is a sectional view with parts in side elevation showing another heating element embodiment used in an electric furnace.
  • our heating element comprises a solid core member 12 made of tungsten, graphite, carbon or molybdenum.
  • Member 12 may be a straight rod or wire, as shown, or it may be formed into a loop or coil depending upon the particular application.
  • element 10 is heated by passing an electric current through it.
  • a pair of sleeve-like electrodes 16a and 1612 are engaged over the ends of the element and these are connected by electrical leads 18a and 18b to a standard power supply 20.
  • Electrodes 16a and 16b are made of a highly thermally conductive metal such as brass and they are relatively massive so that they can also function as heat sinks to cool the ends of the heating element in the vicinity of its electrical connections to power supply 20.
  • element 10 can operate in air at precisely controlled very high temperatures, in excess of 1300 C., for a relatively long period without failure. Moreover, it can be recycled between these high temperatures and room temperature many times without appreciably shortening its operating life.
  • Coating 14 is an alloy composed of aluminum and a metal selected from the group consisting of indium, tin and gallium; and a preferred coating also includes tungsten.
  • the coating ingredients are melted and thoroughly mixed. Then the core member is dipped into the molten alloy. Alternatively, the coating may be sprayed or sputtered directly onto the surface of member 12. At room temperature, the alloy coating 14 forms a solid sheath which clads member 12. Over most of the operating range of the heating element, however, coating 14 is partially liquid so that it forms a flowable, oxidation-resistant film on the surface of member 12 which protects the latter from atmospheric corrosion. The fact that the alloy coating is flowable when element 10 is in use insures that the protective film is continuous over the entire surface of core member 12. Thus, no part of that member is exposed to the atmosphere. Also, the alloy coating is able to follow readily the expansions and contractions of core member 12 as that changes temperature so that there is no breach in the alloy coating at any point in the operating cycle.
  • the coating ingredients coact as they do to enable element 10 to withstand such high temperatures in air is not altogether understood. It is believed, however, that the aluminum forms a protective oxide film on the surface of the coating.
  • the indium, tin or gallium provide a low melting fluid medium which is essentially nonreactive and, when used in conjunction with the other coating components, remain in equilibrium with the underlying core material so that the oxide film tends continuously to heal itself.
  • Aluminum, without indium, tin or gallium does not possess this healing capability and does not appreciably improve the operating life of the heating element.
  • coating 14 also includes tungsten.
  • This material increases the viscosity of the coating alloy so that a coating of optimum thickness can be applied (i.e. 8-20 mils).
  • the tungsten component in coating 14 minimizes attack on the core member.
  • member 12 is made of graphite
  • the tungsten in the coating serves to enhance the adherence of the coating to the graphite. For these reasons, tungsten improves the oxidation protection afforded member 12 and thereby raises the operating temperature of element 10 and prolongs its useful life.
  • oxidation protection is maximized if a small amount of the tungsten in the coating is replaced by boron.
  • the boron content of coating 14 can be as high as 10% by weight, the preferred amount of boron is found to be between 0.5% and 2%, with 1% being the optimum. In any event, the tungsten content of the coating should still be at least 5% by weight as shown by area DEFG in FIG. 2.
  • gold, silver or copper may be substituted for a minor part of the indium, tin or gallium.
  • a minor amount of aluminum i.e. up to 30 wt. percent may be replaced by chromium.
  • EXAMPLE 1 A coating was applied to a 0.125 inch diameter, 4 inch long, tungsten rod to a thickness of approximately 8 mils.
  • the coating composition by weight percent was as follows (see point 1 in FIG. 2):
  • the temperature of the heating element was raised immediately to 1820 C. by passing a current through it.
  • the heating element was maintained at this temperature for 23 /2 hours in open air before failure. Failure was indicated, as in all the other tests, by a trail of core material oxide vapor originating from a point on the heating element.
  • Example 1 a heating element made in accordance with Example 1 was cycled in second intervals from room temperature to 1800 C. and down again for 50 cycles without failure or flaking of the coating.
  • EXAMPLE 2 A heating element consisting of a 0.100 diameter tungsten rod core member was coated with the Example 1 coating material. This element was heated to 1900 C. and maintained at that temperature for four hours in open air before failure.
  • a heating element having a 0.175 inch diameter tungsten rod as a core member had a coating of the following composition (see point 4 in FIG. 2)
  • EXAMPLE 5 A heating element having a 0.100 inch diameter tungsten rod as a core member was coated with an alloy of the following composition (see point 5 in FIG. 2):
  • a heating element having a tungsten rod core member had an alloy coating of the following composition (see point 6 in FIG. 2)
  • EXAMPLE 7 A similar tungsten core element had an alloy coating of the following composition (see point 7 in FIG. 2):
  • EXAMPLE 8 I A heating element consisting of 0.100 inch diameter W-shaped tungsten rod was coated with an alloy of the following composition (see point 8 in FIG. 2):
  • heating elements consisting of equivalent uncoated core members burn out in seconds when operated in air at these high temperatures. Failure is immediately apparent by the presence of smoke issuing from a point on the heating element indicating the formation of an oxide of the core material.
  • a heating element of this type is indicated generally at 24 in FIG. 3.
  • the element has a solid core member 26 similar to member 12 in FIG. 1.
  • a pair of larger diameter cylindrical graphite end pieces 28a and 2812 have axial bores 30a and 30b which are arranged to snugly receive the ends of rod 26.
  • an alloy coating 32 having a composition defined by the shaded areas in FIG. 2 is applied to member 26 as well as to the graphite end pieces 28a and 28b.
  • Element 24 is heated by passing an electrical current through it by way of electrodes 34a and 34b which engage over end pieces 28a and 28b. These electrodes also act as heat sinks. The electrodes are normally positioned so that the portions of end pieces 28a and 28b adjacent rod 26 project out from the electrodes about /2 to inch. Actually, only these projecting portions need be coated because the remainders of the end pieces within the electrodes (heat sinks) are kept sufiiciently cool that they suffer no oxidation.
  • these formations are due initially to the differential expansion of the molten alloy coating 32 and tungsten core member 26, together with the restrictive effect on the coating of the graphite end 'pieces 28a and 28b. Further, tests indicate that there may be a chemical as well as a physical effect produced by this construction. That is, these formations 36a and 36b have been found after testing to be black to metallic grey in color and very hard to grind. While their composition is not known exactly, they have the appearance and characterisics of a metallic-bonded, mixed oxide-carbide material.
  • EXAMPLE 9 A heating element consisting of a 0.175 inch diameter tungsten rod and graphite end pieces approximately 1% inch long and A; inch in diameter were coated with the alloy of Example 1. The element was mounted in brass heat sinks with the graphite ends protruding as described above in connection with FIG. 3. Electric current was passed through the element to bring it rapidly to 1820 C. This element remained operating at this temperature in air for 44 hours before failure. An element made of a similarly coated tungsten rod, but without the graphite end pieces failed after 23 /2 hours at this temperature.
  • Example 4 alloy Another heating element having a similar tungsten rod core and graphite end pieces was coated with the Example 4 alloy. This element operated in air at 1820" C. for 47 /2 hours without failure at the time the test was terminated.
  • the electrical contacts to the element may become overheated unless steps are taken to prevent this. This may be done, for example, by cooling electrodes 34a and 34b by circulating water through them.
  • the graphite end pieces 28a and 28b being of relatively large diameter, do not generate appreciable heat during the passage of current through the element as compared with the coated core member 26. Therefore, they are often cool enough to serve as the electrical leads for the element where they etxend through the thermal insulation of a furnace wall.
  • FIG. 4 illustrates another heating element embodiment indicated generally at 40 mounted in a refractory insulating furnace wall 42. Only one side of the furnace wall and one end of the element are shown.
  • Heating element 40 comprises a tungsten rod core member 44 having a larger diameter graphite end piece 46 similar to end piece 28:: in FIG. 3.
  • a coating 47 of the type described above covers core member 44 and end piece 46 as described above in connection with FIG. 3.
  • the graphite end piece 46 is snugly received in a passage 48 in furnace wall 42.
  • the element is positioned in this passage so that the coated core member 44, as well as an inch or so of the coated end piece 46, project out of passage 48 into the furnace cavity 50.
  • End piece 46 thus supports the coated rod 44 and serves as an electrical lead within the intermediate temperature zone inside the furnace wall.
  • the end piece may extend entirely through the wall.
  • a rod 52 of thermally conductive metal such as aluminum can substitute for the this event, the aluminum rod has a reduced diameter threaded end portion 52a which screws into a correspondingly threaded axial bore 46a in end piece 46.
  • the utilization of the aluminum rod 52 is desirable in some cases because the aluminum is less expensive and stronger than the coated graphite.
  • a rather massive thermally conductive electrode-heat sink 54 snugly engages over aluminum rod 52 within wall 42, the passage 48 through the wall being enlarged at 48a to accommodate it.
  • the graphite and' aluminum members 46 and 52 serve as conductors for the element 40* in the cooler regions of the furnace, connecting the element both electrically and thermally to the heat sink 54.
  • our heating elements are all self-supporting and, unlike some conventional units which operate at much lower temperatures, they do not sag appreciably even at their maximum service temperature, i.e. 1900 C.
  • our elements can be suspended within a furnace chamber solely by their end leads. This is highly desirable because any contact with the hot midportion of the element can result in contamination and have a deleterious effect on the elements performance.
  • this can be accomplished using a high purity alumina ceramic (e.g. 99% A1 0 provided that there is no appreciable abrasion of the coated surface when the element is in use.
  • the elements described herein are advantaged also in that they are rugged, nonbrittle, durable and have no tendency to buckle or sag in use. Moreover, they can withstand repeated temperature cyclings over their operating ranges without seriously shortening their operating lives.
  • a structure capable of withstanding very high temperatures in air comprising (A) a core member made of at least one refractory material selected from the group consisting of tungsten, graphite, carbon and molybdenum, and
  • alloy coating also contains a minor amount of at least one metal selected from the group consisting of gold, silver and copper.
  • An improved oxidation-resistant electrical heating element comprising (A) an electrically conducting core member composed of at least one material selected from the group consisting of tungsten, graphite, carbon and molybdenum, and
  • An improved heating element as defined in claim 15 wherein up to 10% by weight of said tungsten is substituted for by boron.
  • heating element defined in claim 9 wherein up to 30% by weight of said aluminum is substituted for by chromium.
  • said alloy coating also contains a minor amount of at least one metal selected from the group consisting of gold, silver and copper.
  • said coating contains at least 5% by weight of tungsten.
  • An improved high temperature electric furnace comprising (A) thermally insulated container,
  • each said element comprising (1) a refractory core member, and

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  • Resistance Heating (AREA)
  • Furnace Details (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)
  • Crucibles And Fluidized-Bed Furnaces (AREA)
US810318A 1969-03-25 1969-03-25 Oxidation resistant high temperature structures Expired - Lifetime US3538231A (en)

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DE (1) DE2014480A1 (de)
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GB (1) GB1301265A (de)

Cited By (48)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4010352A (en) * 1975-05-21 1977-03-01 Bert Phillips ZrO2 -base heating elements
US4187344A (en) * 1978-09-27 1980-02-05 Norton Company Protective silicon nitride or silicon oxynitride coating for porous refractories
US4205045A (en) * 1977-03-22 1980-05-27 Chemische Werke Buls A.G. Radial-flow reactor with heatable catalyst filling
US4206492A (en) * 1976-02-17 1980-06-03 Gte Laboratories Incorporated Electric gas ignitor utilizing a fiber ignition element
US4241292A (en) * 1978-10-20 1980-12-23 Sanders Associates, Inc. Resistive heater
US4806508A (en) * 1986-09-17 1989-02-21 Lanxide Technology Company, Lp Modified ceramic structures and methods of making the same
US4808558A (en) * 1987-08-26 1989-02-28 Lanxide Technology Company, Lp Ceramic foams
US4818454A (en) * 1986-09-16 1989-04-04 Lanxide Technology Company, Lp Method of making ceramic composite articles by inverse shape replication of an expendable pattern
US4820461A (en) * 1986-09-16 1989-04-11 Lanxide Technology Company, Lp Production of ceramic articles incorporating porous filler material
US4822759A (en) * 1986-09-16 1989-04-18 Lanxide Technology Company, Lp Ceramic composite structures having intrinsically fitted encasement members thereon & methods of making the same
US4824622A (en) * 1986-12-22 1989-04-25 Lanxide Technology Company, Lp Method of making shaped ceramic composites
US4828785A (en) * 1986-01-27 1989-05-09 Lanxide Technology Company, Lp Inverse shape replication method of making ceramic composite articles
US4830799A (en) * 1987-01-07 1989-05-16 Lanxide Technology Company, Lp Method of making shaped ceramic articles by shape replication of an expendable pattern
US4833110A (en) * 1986-09-16 1989-05-23 Lanxide Technology Company, Lp Method for producing composite ceramic structures
US4834925A (en) * 1987-01-07 1989-05-30 Lanxide Technology Company, Lp Method for producing mold-shaped ceramic bodies
US4837232A (en) * 1986-09-16 1989-06-06 Lanxide Technology Company, Lp Dense skin ceramic structure and method of making the same
US4847220A (en) * 1986-09-17 1989-07-11 Lanxide Technology Company, Lp Method of making ceramic composites
US4847025A (en) * 1986-09-16 1989-07-11 Lanxide Technology Company, Lp Method of making ceramic articles having channels therein and articles made thereby
US4859640A (en) * 1986-08-13 1989-08-22 Lanxide Technology Company, Lp Method of making ceramic composite articles with shape replicated surfaces
US4867758A (en) * 1986-08-07 1989-09-19 Lanxide Technology Company, Lp Method for producing ceramic abrasive materials
US4882306A (en) * 1986-09-16 1989-11-21 Lanxide Technology Company, Lp Method for producing self-supporting ceramic bodies with graded properties
US4886766A (en) * 1987-08-10 1989-12-12 Lanxide Technology Company, Lp Method of making ceramic composite articles and articles made thereby
US4891345A (en) * 1986-09-16 1990-01-02 Lanxide Technology Company, Lp Method for producing composite ceramic structures using dross
US4900699A (en) * 1986-09-16 1990-02-13 Lanxide Technology Company, Lp Reservoir feed method of making ceramic composite structures and structures made thereby
US4921818A (en) * 1986-09-17 1990-05-01 Lanxide Technology Company, Lp Method of making ceramic composites
US4923832A (en) * 1986-05-08 1990-05-08 Lanxide Technology Company, Lp Method of making shaped ceramic composites with the use of a barrier
US4948764A (en) * 1986-09-16 1990-08-14 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles with surface coatings
US4956338A (en) * 1987-07-06 1990-09-11 Lanxide Technology Company, Lp Methods for forming complex oxidation reaction products including superconducting articles
US4981632A (en) * 1986-09-16 1991-01-01 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles incorporating filler materials
US5017526A (en) * 1986-05-08 1991-05-21 Lanxide Technology Company, Lp Methods of making shaped ceramic composites
US5024794A (en) * 1986-09-16 1991-06-18 Lanxide Technology Company, Lp Self-supporting ceramic structures and methods of making the same
US5064788A (en) * 1986-09-16 1991-11-12 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles with surface coatings
US5073527A (en) * 1984-07-20 1991-12-17 Lanxide Technology Company, Lp Self-supporting ceramic materials
US5102864A (en) * 1987-07-06 1992-04-07 Lanxide Technology Company, Lp Methods for forming complex oxidation reaction products including superconducting articles
US5106789A (en) * 1986-09-17 1992-04-21 Lanxide Technology Company, Lp Method of making ceramic composites
US5118647A (en) * 1984-03-16 1992-06-02 Lanxide Technology Company, Lp Ceramic materials
US5134102A (en) * 1986-09-16 1992-07-28 Lanxide Technology Company, Lp Method for producing composite ceramic structures using dross
US5162273A (en) * 1986-05-08 1992-11-10 Lanxide Technology Company, Lp Shaped ceramic composites and methods of making the same
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US5246895A (en) * 1986-09-17 1993-09-21 Lanxide Technology Company, Lp Method of making ceramic composites
US5248476A (en) * 1992-04-30 1993-09-28 The Indium Corporation Of America Fusible alloy containing bismuth, indium, lead, tin and gallium
US5254511A (en) * 1986-09-16 1993-10-19 Lanxide Technology Company, Lp Method for producing composite ceramic structures using dross
US5306677A (en) * 1984-03-16 1994-04-26 Lanxide Technology Company, Lp Ceramic materials
US5306676A (en) * 1993-03-09 1994-04-26 Lanxide Technology Company, Lp Silicon carbide bodies and methods of making the same
US5334562A (en) * 1985-02-04 1994-08-02 Lanxide Technology Company, Lp Composite ceramic articles
US5340655A (en) * 1986-05-08 1994-08-23 Lanxide Technology Company, Lp Method of making shaped ceramic composites with the use of a barrier and articles produced thereby
US5516595A (en) * 1986-09-16 1996-05-14 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles with surface coatings
US5523270A (en) * 1987-07-06 1996-06-04 Lanxide Technology Company, Lp Complex perovskite oxidation reaction products

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DE202009018409U1 (de) 2009-12-22 2011-11-29 Htm Reetz Gmbh Elektrisches Heizelement für Hochtemperaturöfen
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US4010352A (en) * 1975-05-21 1977-03-01 Bert Phillips ZrO2 -base heating elements
US4206492A (en) * 1976-02-17 1980-06-03 Gte Laboratories Incorporated Electric gas ignitor utilizing a fiber ignition element
US4205045A (en) * 1977-03-22 1980-05-27 Chemische Werke Buls A.G. Radial-flow reactor with heatable catalyst filling
US4187344A (en) * 1978-09-27 1980-02-05 Norton Company Protective silicon nitride or silicon oxynitride coating for porous refractories
US4241292A (en) * 1978-10-20 1980-12-23 Sanders Associates, Inc. Resistive heater
US5118647A (en) * 1984-03-16 1992-06-02 Lanxide Technology Company, Lp Ceramic materials
US5306677A (en) * 1984-03-16 1994-04-26 Lanxide Technology Company, Lp Ceramic materials
US5073527A (en) * 1984-07-20 1991-12-17 Lanxide Technology Company, Lp Self-supporting ceramic materials
US5334562A (en) * 1985-02-04 1994-08-02 Lanxide Technology Company, Lp Composite ceramic articles
US4828785A (en) * 1986-01-27 1989-05-09 Lanxide Technology Company, Lp Inverse shape replication method of making ceramic composite articles
US5358914A (en) * 1986-05-08 1994-10-25 Lanxide Technology Company, Lp Methods of making shaped ceramic composites
US5162273A (en) * 1986-05-08 1992-11-10 Lanxide Technology Company, Lp Shaped ceramic composites and methods of making the same
US5017526A (en) * 1986-05-08 1991-05-21 Lanxide Technology Company, Lp Methods of making shaped ceramic composites
US5356720A (en) * 1986-05-08 1994-10-18 Lanxide Technology Company, Lp Shaped self-supporting ceramic composite bodies comprising silicon nitrides
US4923832A (en) * 1986-05-08 1990-05-08 Lanxide Technology Company, Lp Method of making shaped ceramic composites with the use of a barrier
US5340655A (en) * 1986-05-08 1994-08-23 Lanxide Technology Company, Lp Method of making shaped ceramic composites with the use of a barrier and articles produced thereby
US4867758A (en) * 1986-08-07 1989-09-19 Lanxide Technology Company, Lp Method for producing ceramic abrasive materials
US4859640A (en) * 1986-08-13 1989-08-22 Lanxide Technology Company, Lp Method of making ceramic composite articles with shape replicated surfaces
US4948764A (en) * 1986-09-16 1990-08-14 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles with surface coatings
US4882306A (en) * 1986-09-16 1989-11-21 Lanxide Technology Company, Lp Method for producing self-supporting ceramic bodies with graded properties
US5344690A (en) * 1986-09-16 1994-09-06 Lanxide Technology Company, Lp Ceramic articles having channels for regulating the passage of fluids
US4981632A (en) * 1986-09-16 1991-01-01 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles incorporating filler materials
US4891345A (en) * 1986-09-16 1990-01-02 Lanxide Technology Company, Lp Method for producing composite ceramic structures using dross
US4900699A (en) * 1986-09-16 1990-02-13 Lanxide Technology Company, Lp Reservoir feed method of making ceramic composite structures and structures made thereby
US5254511A (en) * 1986-09-16 1993-10-19 Lanxide Technology Company, Lp Method for producing composite ceramic structures using dross
US4833110A (en) * 1986-09-16 1989-05-23 Lanxide Technology Company, Lp Method for producing composite ceramic structures
US5516595A (en) * 1986-09-16 1996-05-14 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles with surface coatings
US4847025A (en) * 1986-09-16 1989-07-11 Lanxide Technology Company, Lp Method of making ceramic articles having channels therein and articles made thereby
US4837232A (en) * 1986-09-16 1989-06-06 Lanxide Technology Company, Lp Dense skin ceramic structure and method of making the same
US4822759A (en) * 1986-09-16 1989-04-18 Lanxide Technology Company, Lp Ceramic composite structures having intrinsically fitted encasement members thereon & methods of making the same
US5024794A (en) * 1986-09-16 1991-06-18 Lanxide Technology Company, Lp Self-supporting ceramic structures and methods of making the same
US5064788A (en) * 1986-09-16 1991-11-12 Lanxide Technology Company, Lp Production of ceramic and ceramic-metal composite articles with surface coatings
US4820461A (en) * 1986-09-16 1989-04-11 Lanxide Technology Company, Lp Production of ceramic articles incorporating porous filler material
US5196271A (en) * 1986-09-16 1993-03-23 Lanxide Technology Company, Lp Method of making ceramic articles having channels therein and articles made thereby
US4818454A (en) * 1986-09-16 1989-04-04 Lanxide Technology Company, Lp Method of making ceramic composite articles by inverse shape replication of an expendable pattern
US5134102A (en) * 1986-09-16 1992-07-28 Lanxide Technology Company, Lp Method for producing composite ceramic structures using dross
US5246895A (en) * 1986-09-17 1993-09-21 Lanxide Technology Company, Lp Method of making ceramic composites
US4806508A (en) * 1986-09-17 1989-02-21 Lanxide Technology Company, Lp Modified ceramic structures and methods of making the same
US5106789A (en) * 1986-09-17 1992-04-21 Lanxide Technology Company, Lp Method of making ceramic composites
US4921818A (en) * 1986-09-17 1990-05-01 Lanxide Technology Company, Lp Method of making ceramic composites
US4847220A (en) * 1986-09-17 1989-07-11 Lanxide Technology Company, Lp Method of making ceramic composites
US4824622A (en) * 1986-12-22 1989-04-25 Lanxide Technology Company, Lp Method of making shaped ceramic composites
US4834925A (en) * 1987-01-07 1989-05-30 Lanxide Technology Company, Lp Method for producing mold-shaped ceramic bodies
US4830799A (en) * 1987-01-07 1989-05-16 Lanxide Technology Company, Lp Method of making shaped ceramic articles by shape replication of an expendable pattern
US5102864A (en) * 1987-07-06 1992-04-07 Lanxide Technology Company, Lp Methods for forming complex oxidation reaction products including superconducting articles
US4956338A (en) * 1987-07-06 1990-09-11 Lanxide Technology Company, Lp Methods for forming complex oxidation reaction products including superconducting articles
US5523270A (en) * 1987-07-06 1996-06-04 Lanxide Technology Company, Lp Complex perovskite oxidation reaction products
US4886766A (en) * 1987-08-10 1989-12-12 Lanxide Technology Company, Lp Method of making ceramic composite articles and articles made thereby
US4808558A (en) * 1987-08-26 1989-02-28 Lanxide Technology Company, Lp Ceramic foams
US5248476A (en) * 1992-04-30 1993-09-28 The Indium Corporation Of America Fusible alloy containing bismuth, indium, lead, tin and gallium
US5436208A (en) * 1993-03-09 1995-07-25 Lanxide Technology Company, Lp Silicon carbide bodies and methods of making the same
US5306676A (en) * 1993-03-09 1994-04-26 Lanxide Technology Company, Lp Silicon carbide bodies and methods of making the same

Also Published As

Publication number Publication date
FR2046158A5 (de) 1971-03-05
DE2014480A1 (de) 1970-12-17
GB1301265A (de) 1972-12-29

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