US2993814A - Heating conductor and method of making the same - Google Patents

Heating conductor and method of making the same Download PDF

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US2993814A
US2993814A US814299A US81429959A US2993814A US 2993814 A US2993814 A US 2993814A US 814299 A US814299 A US 814299A US 81429959 A US81429959 A US 81429959A US 2993814 A US2993814 A US 2993814A
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coating
heating
silicon carbide
bars
making
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US814299A
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Epprecht Wilfried
Held Fritz
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Gesellschaft zur Foerderung der Forschung an der Eidgenoessischen Technischen Hochschule
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Gesellschaft zur Foerderung der Forschung an der Eidgenoessischen Technischen Hochschule
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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
    • H01B1/04—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of carbon-silicon compounds, carbon or silicon
    • 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
    • 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
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49002—Electrical device making
    • Y10T29/49082—Resistor making
    • Y10T29/49099—Coating resistive material on a base
    • 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
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2918—Rod, strand, filament or fiber including free carbon or carbide or therewith [not as steel]
    • 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
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2933—Coated or with bond, impregnation or core
    • Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
    • Y10T428/2958—Metal or metal compound in 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
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2913—Rod, strand, filament or fiber
    • Y10T428/2933—Coated or with bond, impregnation or core
    • Y10T428/294—Coated or with bond, impregnation or core including metal or compound thereof [excluding glass, ceramic and asbestos]
    • Y10T428/296—Rubber, cellulosic or silicic material in coating

Definitions

  • Silicon carbide and carbon incandescent bars are known. Further, heating conductors are already known that consist of a carbonaceous core with a coating containing molybdenum and resistant to oxidizing. Finally, also metallic molybdenum heating conductors are known, which have a coating containing molybdenum silicide and resistant to oxidizing.
  • the invention consists principally in the utilizaton of the coating known per se, containing molybdenum and resistant to oxidizing, on silicon carbide bars that are also known. Silicon carbide bars provided with the mentioned oxidizing-resistant coating have essentially the following advantages over the carbon incandescent bars prw vided with a corresponding coating.
  • the silicon carbide bar with coating-containing molybdenum has a lower electric conductivity than the conventional carbon bars with corresponding coating. This means, that when the known carbon heating bars are used as incandescent bodies, much higher strengths of current are needed than for the bar according to the invention; that accordingly the conventional coated carbon incandescent bars require much larger transformers, that the current leads are more expensive, etc. Because of the aforementioned reasons, the bars according to the invention are particularly suitable exactly for industrial furnaces. In addition, many existing furnaces are ar ranged to take silicon carbide bars, so that the bars according to the invention, which correspond electrically to the pure silicon carbide bars, can be built-in directly into existing furnaces, whereas the coated carbon bars necessitate modifications in the construction of the furnaces.
  • the thermal conductivity of the bar according to the present invention is more favorable than in the case of the conventional incandescent carbon bars, since it is lower.
  • no cooled bar holders will be needed, as are required for the incandescent carbon bars.
  • the bar according to the invention has the advantage that the heating bars are protected against oxidation, so that at high temperatures they are many times superior to the unprotected heating conductors as regards service life.
  • the whole protective coating consists of brittle, hard molybdenum silicon double carbide. If this protective coating is only very slightly damaged when being built into a furnace or when in service, the whole carbon body may when in service in the oxidizing furnace atmospherebe very quickly burned through at the slightly damaged place.
  • the bar according to the present invention has a protective coating consisting internally of still free molybdenum silicide, and externally of a molybdenum compound that is ductile at servicetemperatures. If the protective coating is slightly damaged, there exist three advantages in the subsequent service as compared with the conventional bar:
  • the protective coating in; the vicinity of the damage is viscous like glass and capable: of assisting the self-healing action of the fresh protective material mentioned above in (b).
  • the. bar according to the invention remains thoroughly serviceable, even if the protective: coating has become damaged as may happen in every service, whereas the conventional coated carbon bar will very quickly become useless it slightly damaged.
  • the method of making the heating conductor consists principallyin that the powdered molybdenum silicide is brought onto the silicon carbide by dusting or by spraying.
  • the powder may also be applied by painting-on pastes to which adhesive means may be added or not.
  • the oxidation-resisting coating will be finished by sintering and oxidizing the molybdenum silicide onto the silicon carbide bar.
  • this coating is fused onto a core including carbon. This type of application is not possible in the case of the method according to the invention. Should it be desired to fuse molybdenum silicide onto a silicon carbide core, reactions would occur between the molybdenum silicide coating and the silicon carbide core which would render it impossible for the coating layer to combine with or to adhere to the core.
  • the manner of applying the coating according to the invention is also much simpler and more economical than the fusing of the coating layer onto carbon bars according to the conventional methods.
  • the application need not be effected in vacuum or under a protective gas, as in the conventional methods.
  • the bars according to the invention may be finished at an appreciably lower temperature, and even in the air or without using any inert atmosphere; they may therefore be formed in large quantities together in a furnace at a temperature of about 1450" C., whereas the conventional bars must be made singly and with heating up to about 2300" C.
  • FIG. 1 shows the improved heating body in side elevation
  • FIG. 2 is a transverse section on line 2-2 of FIG. 1.
  • the invention it has been found that it is possible to have silicon carbide heating bodies coated with a thin layer of molybdenum silicide, and then to convert this wholly or partly into the glass-like sintered layer in oxidizing atmosphere.
  • This thin, gastight coating is capable of protecting the silicon carbide against oxidation, so that silicon carbide heating conductors treated in this way may be used at higher temperatures and during longer service periods than unprotected heating conductors.
  • the heating conductor according to the invention thus consists for the most part of almost pure silicon carbide with its economically favorable heatconducting properties and of a thin protective coating, made of molybdenum silicide and being especially highly resistant to oxidation.
  • the essence of the invention is based on the novel combination of the good heating conductor qualities of silicon carbide with the high resistance to scaling of the molybdenum silicide and/or of its oxidation-product.
  • more or less pure, powdered molybdenum silicide can be brought onto the silicon carbide heating bodies in any desired way, say, by dusting, spraying, painting in the form of a paste in pure water or in water with adhesive additives, for example, tragacanth or methyl cellulose, dipping in aqueous pastes with or without the said type of adhesive additives.
  • the heated bodies treated in this way i.e. provided with a coating, are at first dried and then rendered incandescent for sometime in air or an oxidizing atmosphere at a high temperature between 1300 and 1500" C.
  • this incandescence be effected from the outside, i.e. in a furnace, whereas in other cases a heating by passing a current through, or both methods, may be adopted.
  • some white fumes of molybdenum trioxide may be given olf at the start; the main portion of the molybdenum silicide, however, passes into the glass-like protective layer which includes molybdenum, silicon, oxygen and partly also carbon, and covers the heating chamber tight, the protective layer being firmly sintered on.
  • the heating bodies may be used at all temperatures up to over 1500" C. without any more molybdenum trioxide being given olf in fumes.
  • Heating conductor composed of a conductor consisting essentially of silicon carbide with a coating of mo lybdenum silicide sintered on the conductor and resistant to oxidizing.
  • the method of making a heating conductor which comprises the steps of applying pulverulent molybdenum silicide in the form of a coating to the surface of a body consisting essentially of silicon carbide, and then sintering said coating on said body by heating to incandescence at a temperature of between 1300" C. and 1500 C.

Description

July 1951 w. EPPRECHT ET AL 2,993,814
HEATING CONDUCTOR AND METHOD OF MAKING THE SAME Filed May 19, 1959 W/[frifli Epprechf Frivfz Held INVENTORS BY v 40 l United States Patent 2,993,814 HEATING CONDUCTOR AND METHOD OF MAKING THE SAME Wilfried Epprecht, Zurich, and Fritz Held, Forch, Zurich, Switzerland, assiguors to Gesellschaft zur Fiirderung der Forschung an der Eidg. Techn. Hochschule, Zurich, Switzerland Filed May 19, 1959, Ser. No. 814,299 Claims priority, application Switzerland May 24, 1958 4 Claims. (Cl. 117-201) This invention relates to a heating conductor and a method of making the same.
Silicon carbide and carbon incandescent bars are known. Further, heating conductors are already known that consist of a carbonaceous core with a coating containing molybdenum and resistant to oxidizing. Finally, also metallic molybdenum heating conductors are known, which have a coating containing molybdenum silicide and resistant to oxidizing. The invention consists principally in the utilizaton of the coating known per se, containing molybdenum and resistant to oxidizing, on silicon carbide bars that are also known. Silicon carbide bars provided with the mentioned oxidizing-resistant coating have essentially the following advantages over the carbon incandescent bars prw vided with a corresponding coating.
The silicon carbide bar with coating-containing molybdenum has a lower electric conductivity than the conventional carbon bars with corresponding coating. This means, that when the known carbon heating bars are used as incandescent bodies, much higher strengths of current are needed than for the bar according to the invention; that accordingly the conventional coated carbon incandescent bars require much larger transformers, that the current leads are more expensive, etc. Because of the aforementioned reasons, the bars according to the invention are particularly suitable exactly for industrial furnaces. In addition, many existing furnaces are ar ranged to take silicon carbide bars, so that the bars according to the invention, which correspond electrically to the pure silicon carbide bars, can be built-in directly into existing furnaces, whereas the coated carbon bars necessitate modifications in the construction of the furnaces.
Also the thermal conductivity of the bar according to the present invention is more favorable than in the case of the conventional incandescent carbon bars, since it is lower. In addition, no cooled bar holders will be needed, as are required for the incandescent carbon bars.
Moreover, in comparison with the usual silicon car- 'bide bars, the bar according to the invention has the advantage that the heating bars are protected against oxidation, so that at high temperatures they are many times superior to the unprotected heating conductors as regards service life. Finally, there is still another important advantage:
In the case of the conventional coated carbon bar, the whole protective coating consists of brittle, hard molybdenum silicon double carbide. If this protective coating is only very slightly damaged when being built into a furnace or when in service, the whole carbon body may when in service in the oxidizing furnace atmospherebe very quickly burned through at the slightly damaged place. On the other hand, the bar according to the present invention has a protective coating consisting internally of still free molybdenum silicide, and externally of a molybdenum compound that is ductile at servicetemperatures. If the protective coating is slightly damaged, there exist three advantages in the subsequent service as compared with the conventional bar:
(a) The exposed silicon carbide does not oxidize like ice carbon with the formation of volatile CO or C0,, until the whole bar has burnt, but solid Si0 will be formed, which also locally produces a certain protection against oxidation.
(b) The still existing free molybdenum silicide of the neighboring protective coating reacts with the oxygen of the furnace atmosphere and forms fresh protectivecoating material which can close the gap caused by damage.
(0) At service temperatures the protective coating in; the vicinity of the damage is viscous like glass and capable: of assisting the self-healing action of the fresh protective material mentioned above in (b).
For these reasons, the. bar according to the invention: remains thoroughly serviceable, even if the protective: coating has become damaged as may happen in every service, whereas the conventional coated carbon bar will very quickly become useless it slightly damaged.
The method of making the heating conductor consists principallyin that the powdered molybdenum silicide is brought onto the silicon carbide by dusting or by spraying. The powder may also be applied by painting-on pastes to which adhesive means may be added or not. Finally, it is also possible to have the powder applied by dipping the core into pastes containing adhesive means or not. Thereupon the oxidation-resisting coating will be finished by sintering and oxidizing the molybdenum silicide onto the silicon carbide bar.
In the conventional method of applying a coating containing molybdenum, this coating is fused onto a core including carbon. This type of application is not possible in the case of the method according to the invention. Should it be desired to fuse molybdenum silicide onto a silicon carbide core, reactions would occur between the molybdenum silicide coating and the silicon carbide core which would render it impossible for the coating layer to combine with or to adhere to the core.
The manner of applying the coating according to the invention is also much simpler and more economical than the fusing of the coating layer onto carbon bars according to the conventional methods. The application need not be effected in vacuum or under a protective gas, as in the conventional methods. The bars according to the invention may be finished at an appreciably lower temperature, and even in the air or without using any inert atmosphere; they may therefore be formed in large quantities together in a furnace at a temperature of about 1450" C., whereas the conventional bars must be made singly and with heating up to about 2300" C.
Further features of the invention will appear from the following description and claims, and one embodiment of the invention is illustrated in the accompanying drawings wherein FIG. 1 shows the improved heating body in side elevation, and FIG. 2 is a transverse section on line 2-2 of FIG. 1.
According to the invention it has been found that it is possible to have silicon carbide heating bodies coated with a thin layer of molybdenum silicide, and then to convert this wholly or partly into the glass-like sintered layer in oxidizing atmosphere. This thin, gastight coating is capable of protecting the silicon carbide against oxidation, so that silicon carbide heating conductors treated in this way may be used at higher temperatures and during longer service periods than unprotected heating conductors. The heating conductor according to the invention thus consists for the most part of almost pure silicon carbide with its economically favorable heatconducting properties and of a thin protective coating, made of molybdenum silicide and being especially highly resistant to oxidation.
The metallic molybdenum heating conductors already formerly proposed, with coating of oxidation-resisting molybdenum silicide, behave so very differently mechanically with respect to the metal when heated up and cooled down, that no protective layer is obtained of a lasting nature and free fromcracks. Besides that, such protective coatings on metal are very liable to get damaged, and the exposed metal portions quickly oxidize at a high temperature so as to destroy the heating conductor. In contrast thereto, through the present invention, on the non-metallic silicon carbide heating conductor a very good adhesive. and gasti-ght protective coating of molybdenum silicide and/or its oxidation-product will be obtained, which is not extremely sensitive to damage and capable of withstanding severe thermal-shock treatment. The essence of the invention is based on the novel combination of the good heating conductor qualities of silicon carbide with the high resistance to scaling of the molybdenum silicide and/or of its oxidation-product.
For making the heating conductor according to the in vention, more or less pure, powdered molybdenum silicide can be brought onto the silicon carbide heating bodies in any desired way, say, by dusting, spraying, painting in the form of a paste in pure water or in water with adhesive additives, for example, tragacanth or methyl cellulose, dipping in aqueous pastes with or without the said type of adhesive additives. The heated bodies treated in this way, i.e. provided with a coating, are at first dried and then rendered incandescent for sometime in air or an oxidizing atmosphere at a high temperature between 1300 and 1500" C. It has then been foundsuitable for certain shapes of heating conductors that this incandescence be effected from the outside, i.e. in a furnace, whereas in other cases a heating by passing a current through, or both methods, may be adopted. In the case of this incandescence some white fumes of molybdenum trioxide may be given olf at the start; the main portion of the molybdenum silicide, however, passes into the glass-like protective layer which includes molybdenum, silicon, oxygen and partly also carbon, and covers the heating chamber tight, the protective layer being firmly sintered on. When the molybdenum silicide has 4 once been oxidized, the heating bodies may be used at all temperatures up to over 1500" C. without any more molybdenum trioxide being given olf in fumes.
Through the invention it is possible to make silicon carbide heating conductors which at high temperatures are by far superior to the unprotected heating conductors as regards service life, and also possible to carry out the method favorably as regards economy.
What we claim is:
1. Heating conductor composed of a conductor consisting essentially of silicon carbide with a coating of mo lybdenum silicide sintered on the conductor and resistant to oxidizing.
2. The method of making a heating conductor which comprises the steps of applying pulverulent molybdenum silicide in the form of a coating to the surface of a body consisting essentially of silicon carbide, and then sintering said coating on said body by heating to incandescence at a temperature of between 1300" C. and 1500 C.
3. The method of making a heating conductor as defined in claim 2 wherein in said sintering step the body carrying said coating of pulveru-lent molybdenum silicide is heated to incandesecence in an oxidizing gas by passing electri'current through the body of silicon carbide thereby to sinter the molybdenum silicide onto said body and to form an oxidation-resistant protective layer over the latter.
4. The method of making a heating conducting as defined in claim 2 wherein in said sintering step the body carrying said coating of pulverulent molybdenum silicide is heated to incandescence in a furnace in an oxidizing atmosphere thereby to sinter the molybdenum silicide onto said body and to form an oxidation-resistant protective layer over the latter.
References Cited in the file of this patent UNITED STATES PATENTS 1,814,583 Benner et al. July 14, 1931 1,948,382 Johnson Feb. 20, 1934 2,745,932 Glaser May 15, 1956 Notice of Adverse Decision in Interference In Interference No. 92,360
involving Patent N 0. 2,993,814, TV. Epprecht and F. Held, Heatlng conductor and method of making the same, final judgment adverse to the patentees Was rendered Feb. 13, 1964 as to claims 1 and 2. [Ofiicz'al Gazette August 25, 1.964.]
Notice of Adverse Decision in Interference In Interference N 0. 92,360 involving Patent N 0. 2,993,814, V. Epprecht and F. Held, Heating conductor and method of making the same, final judgment adverse to the patentees was rendered Feb 13, 1964, as to claims 1 and 2. [Ofiicz'al Gazette August 25, 1964.]

Claims (1)

1. HEATING CONDUCTOR COMPOSED OF A CONDUCTOR CONSISTING ESSENTIALLY OF SILICON CARBIDE WITH A COATING OF MOLYBDENUM SILICIDE SINTERED ON THE CONDUCTOR AND RESISTANT TO OXIDIZING.
US814299A 1958-05-24 1959-05-19 Heating conductor and method of making the same Expired - Lifetime US2993814A (en)

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Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3171871A (en) * 1960-07-19 1965-03-02 Norton Co Method of making electrical heater bars
US3390013A (en) * 1964-03-06 1968-06-25 Siemens Planiawerke Ag High-temperature resistant structural body
US3397448A (en) * 1965-03-26 1968-08-20 Dow Corning Semiconductor integrated circuits and method of making same
US3501356A (en) * 1966-05-12 1970-03-17 Westinghouse Electric Corp Process for the epitaxial growth of silicon carbide
US4187344A (en) * 1978-09-27 1980-02-05 Norton Company Protective silicon nitride or silicon oxynitride coating for porous refractories
US4614689A (en) * 1983-04-28 1986-09-30 Kabushiki Kaisha Toshiba Non-oxide-series-sintered ceramic body and method for forming conducting film on the surface of non-oxide-series-sintered ceramic body
DE4331307A1 (en) * 1993-09-15 1995-03-16 Abb Patent Gmbh Manufacture of a composite reinforced with carbon fibers
DE19614676A1 (en) * 1996-04-13 1997-10-16 Choe Kum Chol Process for refining SiC heating elements
US20030183621A1 (en) * 2002-03-20 2003-10-02 Jainagesh Sekhar Treatment for improving the stability of silicon carbide heating elements
US20040207029A1 (en) * 2002-07-16 2004-10-21 Braddock Walter David Junction field effect metal oxide compound semiconductor integrated transistor devices
US20040206979A1 (en) * 2002-06-06 2004-10-21 Braddock Walter David Metal oxide compound semiconductor integrated transistor devices
WO2005061756A1 (en) * 2003-12-09 2005-07-07 Osemi, Inc. High temperature vacuum evaporation apparatus
US20060076630A1 (en) * 2000-05-04 2006-04-13 Braddock Walter D Iv Integrated Transistor devices
US20070138506A1 (en) * 2003-11-17 2007-06-21 Braddock Walter D Nitride metal oxide semiconductor integrated transistor devices

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1814583A (en) * 1927-04-05 1931-07-14 Carborundum Co Method of making electrical resistances
US1948382A (en) * 1931-09-02 1934-02-20 Nat Carbon Co Inc Oxidation resisting carbon article
US2745932A (en) * 1953-06-03 1956-05-15 American Electro Metal Corp Electric resistor

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1814583A (en) * 1927-04-05 1931-07-14 Carborundum Co Method of making electrical resistances
US1948382A (en) * 1931-09-02 1934-02-20 Nat Carbon Co Inc Oxidation resisting carbon article
US2745932A (en) * 1953-06-03 1956-05-15 American Electro Metal Corp Electric resistor

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3171871A (en) * 1960-07-19 1965-03-02 Norton Co Method of making electrical heater bars
US3390013A (en) * 1964-03-06 1968-06-25 Siemens Planiawerke Ag High-temperature resistant structural body
US3397448A (en) * 1965-03-26 1968-08-20 Dow Corning Semiconductor integrated circuits and method of making same
US3501356A (en) * 1966-05-12 1970-03-17 Westinghouse Electric Corp Process for the epitaxial growth of silicon carbide
US4187344A (en) * 1978-09-27 1980-02-05 Norton Company Protective silicon nitride or silicon oxynitride coating for porous refractories
DE2937997A1 (en) * 1978-09-27 1980-05-08 Norton Co POROESE FIREPROOF ITEM WITH PROTECTIVE COVER
US4614689A (en) * 1983-04-28 1986-09-30 Kabushiki Kaisha Toshiba Non-oxide-series-sintered ceramic body and method for forming conducting film on the surface of non-oxide-series-sintered ceramic body
DE4331307C2 (en) * 1993-09-15 2001-02-15 Harald Lorson Manufacture of a carbon fiber reinforced composite and its use
DE4331307A1 (en) * 1993-09-15 1995-03-16 Abb Patent Gmbh Manufacture of a composite reinforced with carbon fibers
DE19614676C2 (en) * 1996-04-13 1998-09-03 Choe Kum Chol Process for refining SiC heating rods
DE19614676A1 (en) * 1996-04-13 1997-10-16 Choe Kum Chol Process for refining SiC heating elements
US7190037B2 (en) 2000-05-04 2007-03-13 Osemi, Inc. Integrated transistor devices
US20060076630A1 (en) * 2000-05-04 2006-04-13 Braddock Walter D Iv Integrated Transistor devices
US7067775B2 (en) * 2002-03-20 2006-06-27 Micropyretics Heaters International, Inc. Treatment for improving the stability of silicon carbide heating elements
US20030183621A1 (en) * 2002-03-20 2003-10-02 Jainagesh Sekhar Treatment for improving the stability of silicon carbide heating elements
US20040206979A1 (en) * 2002-06-06 2004-10-21 Braddock Walter David Metal oxide compound semiconductor integrated transistor devices
US7187045B2 (en) 2002-07-16 2007-03-06 Osemi, Inc. Junction field effect metal oxide compound semiconductor integrated transistor devices
US20040207029A1 (en) * 2002-07-16 2004-10-21 Braddock Walter David Junction field effect metal oxide compound semiconductor integrated transistor devices
US20070138506A1 (en) * 2003-11-17 2007-06-21 Braddock Walter D Nitride metal oxide semiconductor integrated transistor devices
WO2005061756A1 (en) * 2003-12-09 2005-07-07 Osemi, Inc. High temperature vacuum evaporation apparatus
US20080282983A1 (en) * 2003-12-09 2008-11-20 Braddock Iv Walter David High Temperature Vacuum Evaporation Apparatus

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