DE1080313B - Workpieces containing molybdenum disilicide for high temperatures, especially electrical heating elements - Google Patents
Workpieces containing molybdenum disilicide for high temperatures, especially electrical heating elementsInfo
- Publication number
- DE1080313B DE1080313B DES43358A DES0043358A DE1080313B DE 1080313 B DE1080313 B DE 1080313B DE S43358 A DES43358 A DE S43358A DE S0043358 A DES0043358 A DE S0043358A DE 1080313 B DE1080313 B DE 1080313B
- Authority
- DE
- Germany
- Prior art keywords
- workpiece
- high temperatures
- molybdenum disilicide
- temperatures
- disilicide
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
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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
- H01B1/06—Conductors or conductive bodies characterised by the conductive materials; Selection of materials as conductors mainly consisting of other non-metallic substances
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- 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
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/58—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/58085—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicides
- C04B35/58092—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicides based on refractory metal silicides
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- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5025—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with ceramic materials
- C04B41/5035—Silica
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- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5053—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials non-oxide ceramics
- C04B41/5062—Borides, Nitrides or Silicides
- C04B41/5071—Silicides
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- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/51—Metallising, e.g. infiltration of sintered ceramic preforms with molten metal
- C04B41/5133—Metallising, e.g. infiltration of sintered ceramic preforms with molten metal with a composition mainly composed of one or more of the refractory metals
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- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
- C04B41/87—Ceramics
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- 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
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
- C04B41/88—Metals
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Resistance Heating (AREA)
- Ceramic Products (AREA)
Description
I.VIolybdändisilizid enthaltende Werkstücke für hohe Temperaturen, insbesondere elektrisches Heizelement Die Siliziumverbindungen der Übergangsmetalle der IV. bis VI. Gruppe des Periodensystems und vor allem das Molybdändisilizid sind als Werkstoffe für hohe und höchste Temperaturen in oxydierender Atmosphäre mehrfach vorgeschlagen worden. So kann dieses Disilizid in Verbindung mit Silizium oder anderen Hartstoffen bzw. Oxyden als Sinterwerkstoff verwendet werden oder als Schutzschicht auf Molybdänteilen.I. Workpieces containing polybdenum disilicide for high temperatures, in particular electrical heating element The silicon compounds of the transition metals the IV. to VI. Group of the periodic table and especially the molybdenum disilicide as materials for high and very high temperatures in an oxidizing atmosphere several times has been proposed. So this disilicide can be used in conjunction with silicon or others Hard materials or oxides can be used as sintered material or as a protective layer on molybdenum parts.
Die verblüffende Oxydationsbeständigkeit des Molybdändisilizids bis 1700° C wird auf die Ausbildung einer S' 02 haltigen glasartigen Deckschicht beim Glühen an Luft zurückgeführt. Diese Schutzwirkung soll z. B. auch ermöglichen, daß die nach pulvermetallurgischen Methoden geformten Werkstücke nach einer Vorsinterung in reduzierender Atmosphäre bereits in oxydierender Atmosphäre, beispielsweise durch direkte Widerstandserhitzung stabförmiger Teile, hochgesintert werden können.The amazing resistance of molybdenum disilicide to oxidation 1700 ° C is based on the formation of an S '02 containing glass-like cover layer at Glow returned in air. This protective effect should z. B. also allow that the workpieces formed by powder metallurgy methods after pre-sintering in a reducing atmosphere already in an oxidizing atmosphere, for example by direct resistance heating of rod-shaped parts that can be highly sintered.
Es wurde nun gefunden, daß die Ausbildung einer zunderbeständigen Deckschicht nur dann gewährleistet ist, wenn die Oxydation des Molybdändisilizids oberhalb 700'° C stattfindet. Die Zeit bis zur Ausbildung dieser Deckschicht ist abhängig von der Zundertemperatur. Bei 750° C ist die Deckschicht etwa nach 20 bis 50 Stunden aufgebaut, bei 1000° C bereits nach 5 bis 10 Stunden, bei 1400° C nach wenigen Minuten. Zwischen 300 und 700° C, besonders zwischen 500 und 650° C, kommt es überraschenderweise zur sehr raschen Zerstörung des Molybdändisilizids bei Angriff durch Sauerstoff. So wurden Sinterkörper bei 550° C durch Sauerstoffstrom in wenigen Stunden bis zum vollständigen Zerfall zu graugrünem Pulver zerstört. Die Zerstörung geht anscheinend von den Korngrenzen aus unter Abspaltung von Mo Si, -Metallteilchen, die von Oxyden eingehüllt sind. Die Zerstörung wird durch einen höheren Siliziumgehalt nicht beeinflußt, obwohl diese Maßnahme bekanntlich die Zunderbeständigkeit des Molybdändisilizids bei hohen und höchsten Temperaturen verbessert. Dieser unerwartete Zerfall des Molybdändisilizids in dem bezeichneten Temperaturbereich tritt in gleicher Weise bei in Wasserstoff- oder in Inertgasatmosphäre hochgesinterten Körpern auf. Er hat zur Folge, daß Werkstücke mit unterschiedlichen Arbeitstemperaturen, z. B. Heizleiter, eben in den Zonen von 350 bis 700° C einen sehr schnellen Zerfall erleiden. So konnte z. B. an Heizleitern beobachtet werden, daß sich im Hochtemperaturteil, also zwischen 1400 und 1700° C, nach kurzer Zeit eine glasige schöne Deckschicht ausbildete, während die Temperaturzone zwischen 300 und 700° C nach etwa 20 bis 50 Stunden einem verstärkten Angriff unterliegt, so daß durch die eintretende Querschnittsverengung und Überhitzung der Heizstab an dieser Stelle abbricht. Die Erfindung betrifft nun Werkstücke für hohe Temperaturen, die aus Molybdändisilizid bestehen bzw. Molybdändisilizid als zunderfeste Komponente an ihrer mit der oxydierenden Atmosphäre in Berührung kommenden Oberfläche enthalten und an gewissen Stellen Arbeitstemperaturen von 30.0 bis 700° C ausgesetzt sind. Bei diesen Temperaturen dürfen die Mo si2 Oberflächen nicht mit gasförmigem Sauerstoff bzw. mit Sauerstoff enthaltender Atmosphäre in Berührung kommen.It has now been found that the formation of a scale resistant Top layer is only guaranteed if the oxidation of the molybdenum disilicide takes place above 700 ° C. The time until this top layer is formed is depending on the scale temperature. At 750 ° C the top layer is about 20 to 50 hours built up, at 1000 ° C already after 5 to 10 hours, at 1400 ° C after few minutes. Between 300 and 700 ° C, especially between 500 and 650 ° C, comes surprisingly, the molybdenum disilicide is destroyed very quickly when attacked by oxygen. Thus, sintered bodies were made in a few at 550 ° C by flowing oxygen Destroyed hours until complete disintegration into gray-green powder. The destruction apparently starts from the grain boundaries with the elimination of Mo Si, metal particles, which are enveloped by oxides. The destruction is caused by a higher silicon content does not affect, although this measure is known to reduce the scaling resistance of the Molybdenum disilicide improved at high and extremely high temperatures. This unexpected one Decomposition of the molybdenum disilicide occurs in the specified temperature range in the same way Point to in the case of highly sintered bodies in a hydrogen or inert gas atmosphere. It has the consequence that workpieces with different working temperatures, eg. B. Heat conductors, in the zones from 350 to 700 ° C, suffer very rapid disintegration. So could z. B. be observed on heating conductors that in the high-temperature part, between 1400 and 1700 ° C, after a short time a beautiful glassy top layer formed while the temperature zone between 300 and 700 ° C after about 20 to 50 hours is subject to an increased attack, so that the cross-sectional constriction that occurs and overheating of the heating element breaks off at this point. The invention now relates to Workpieces for high temperatures, which consist of molybdenum disilicide or molybdenum disilicide as a non-scaling component in contact with the oxidizing atmosphere coming surface and in certain places working temperatures of 30.0 exposed to up to 700 ° C. At these temperatures the Mo si2 surfaces not with gaseous oxygen or with an oxygen-containing atmosphere in Come into contact.
In dem kritischen Temperaturbereich können Mo Si. -Oberflächen nach der Erfindung dadurch geschützt werden, daß diejenigen Werkstückteile, die ständigen Temperaturen zwischen 300 und 700° C ausgesetzt sind, eine vor Verwendung des Werkstücks aufgebrachte gasdichte Schutzschicht, z. B. eine elektrolytisch erzeugte Chromschicht oder eine aufgesinterte T'tandisilizidschicht, besitzen oder aus molybdänsilizidfreiem, zunderbeständigem Werkstoff bestehen, der an dem Glühteil des Werkstücks angeschweißt ist, z. B. aus einer Silber-Silizium-Legierung mit 5°/o Silizium.In the critical temperature range, Mo Si. -Surfaces according to the invention are protected in that those workpiece parts, the permanent Temperatures between 300 and 700 ° C are exposed one before using the workpiece applied gas-tight protective layer, e.g. B. an electrolytically generated chromium layer or a sintered-on T'tandisilizidschicht, or made of molybdenum silicide-free, scale-resistant material that is welded to the glow part of the workpiece is e.g. B. from a silver-silicon alloy with 5% silicon.
Ein sehr einfacher und wirkungsvoller Schutz ist die Ausbildung der glasigen Si 02 haltigen Deckschicht auf Mo Si.-Werkstoffen. Eine solche Deckschicht kann in an sich bekannter Weise durch Glühen der W erkstückteile vor der Verwendung zwischen 350 und 700°C bei Glühtemperaturen oberhalb 1350-'C in Sauerstoff enthaltender Atmosphäre ausgebildet werden.A very simple and effective protection is the formation of the glassy Si 02 -containing cover layer on Mo Si. Materials. Such a cover layer can be formed in a manner known per se by annealing the workpiece parts before use between 350 and 700 ° C. at annealing temperatures above 1350 ° C. in an oxygen-containing atmosphere.
Claims (1)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT1080313X | 1954-09-18 |
Publications (1)
Publication Number | Publication Date |
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DE1080313B true DE1080313B (en) | 1960-04-21 |
Family
ID=3685108
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
DES43358A Pending DE1080313B (en) | 1954-09-18 | 1955-04-01 | Workpieces containing molybdenum disilicide for high temperatures, especially electrical heating elements |
Country Status (1)
Country | Link |
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DE (1) | DE1080313B (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1483298B1 (en) * | 1965-06-11 | 1971-01-28 | Siemens Ag | Electrical contact arrangement between a germanium-silicon semiconductor body and a contact piece and method for producing the same |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE757229C (en) * | 1936-11-20 | 1954-04-22 | Siemens Schuckertwerke A G | Electric heating element, suitable for operation in the open air |
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1955
- 1955-04-01 DE DES43358A patent/DE1080313B/en active Pending
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE757229C (en) * | 1936-11-20 | 1954-04-22 | Siemens Schuckertwerke A G | Electric heating element, suitable for operation in the open air |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE1483298B1 (en) * | 1965-06-11 | 1971-01-28 | Siemens Ag | Electrical contact arrangement between a germanium-silicon semiconductor body and a contact piece and method for producing the same |
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