EP1472197A1 - Ceramic composite material, method for the production thereof, and pencil-type glow plug containing such a composite material - Google Patents

Ceramic composite material, method for the production thereof, and pencil-type glow plug containing such a composite material

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Publication number
EP1472197A1
EP1472197A1 EP02794999A EP02794999A EP1472197A1 EP 1472197 A1 EP1472197 A1 EP 1472197A1 EP 02794999 A EP02794999 A EP 02794999A EP 02794999 A EP02794999 A EP 02794999A EP 1472197 A1 EP1472197 A1 EP 1472197A1
Authority
EP
European Patent Office
Prior art keywords
boron
composite material
ceramic composite
ceramic
starting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP02794999A
Other languages
German (de)
French (fr)
Inventor
Ralf Riedel
Alexander Klonczynski
Wolfgang Dressler
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Original Assignee
Robert Bosch GmbH
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
Priority claimed from DE10243017A external-priority patent/DE10243017B4/en
Application filed by Robert Bosch GmbH filed Critical Robert Bosch GmbH
Publication of EP1472197A1 publication Critical patent/EP1472197A1/en
Withdrawn legal-status Critical Current

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    • 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
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    • 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
    • C04B35/56—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 carbides or oxycarbides
    • C04B35/5603—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 carbides or oxycarbides with a well-defined oxygen content, e.g. oxycarbides
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    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
    • C04B35/62605—Treating the starting powders individually or as mixtures
    • C04B35/62645—Thermal treatment of powders or mixtures thereof other than sintering
    • C04B35/6267—Pyrolysis, carbonisation or auto-combustion reactions
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Definitions

  • Ceramic composite Process for its manufacture and glow pencil candle with such a composite material
  • the invention relates to a ceramic composite material, a method for its production and a glow pencil candle with such a composite material according to the preamble of the independent claims.
  • ceramic composites in particular amorphous Si-0-C ceramics, are used which, in particular due to the partial pyrolysis of organic elements Precursors are won.
  • Sintering lies in the much lower process temperature and the easy processability and formability of polysiloxane resins. This procedure is described in detail in DE 195 38 695 AI.
  • the production of moldings from these ceramic composites is only possible using additional fillers, otherwise shrinkage cracks and pores will occur during pyrolysis.
  • EP 0412 428 B1 it has already been proposed in EP 0412 428 B1 to precisely set the properties of the ceramic composite material obtained, such as its coefficient of thermal expansion, thermal conductivity or specific electrical resistance, using selected fillers in an initial composite.
  • reactive fillers to achieve a better connection of the fillers to the matrix, but also to use inert fillers.
  • the object of the present invention was to provide a ceramic composite material which can be used in a glow plug, with a particularly increased specific electrical resistance, which should be as independent as possible of fillers additionally used in the composite material, and improved durability.
  • the ceramic composite material should have no or as little aging as possible of the functional properties when used in a glow pencil candle, in particular with regard to the heating-up time and glow temperature.
  • improved glazing in the ceramic composite material is achieved, which is at least partially attributable to the formation of boron-containing glasses or corresponding glass-like areas in the composite material with a lower glass transition temperature, and which increases the durability, in particular glow plugs produced therewith.
  • a dense glass layer is now often formed in and or on the surface of the composite material, and there is no oxidation in the interior of the material used, even after longer aging times, for example 100 h, ie no M0O 3 is formed there , M ⁇ 5 Si 3 or crystalline Si0 2 , which facilitates self-healing processes in the material when cracks form and increases its strength overall.
  • the onset of crystallization of a ceramic matrix based on Si-OC formation with the formation of cristobalite is suppressed by the addition of comparatively small amounts of boron at 1300 ° C for 100 h or at 1350 ° C for 8 h, which the durability and thermal shock resistance of the material are also increased.
  • aging of the specific electrical resistance in the ceramic composite material is suppressed by the boron used and an improvement in its functional properties and thus also in a glow pencil candle produced therewith, especially with regard to the heating-up time and glow temperature, is achieved.
  • the manufacturing composite is used in a glow plug, it is also advantageous that this increases the specific electrical resistance of the insulation layer of the glow plug, suppresses undesired aging of the resistance of the insulation layer and / or the conductive layer of the glow plug, and narrows the resistance distribution in the Control layer is achieved, which among other things leads to a reduced effort in production, quality control and resistance classification.
  • FIG. 1 shows the difference in the percentage pyrolysis shrinkage of a boron-containing ceramic composite compared to a boron-free one as a function of the pyrolysis temperature
  • FIG. 2 shows a Raman spectrum of the boron-containing and the boron-free composite material according to FIG. 1 at a temperature of 1325 ° C.
  • FIG. 3 shows the specific electrical resistance of a boron-containing composite material as a function of the exposure time in air at 1300 ° C exposure temperature
  • FIG. 4 dilatometer measurements to determine the thermal expansion coefficient of a boron-containing composite material compared to a boron-free one as a function of the exposure time in air at 1300 ° C exposure temperature.
  • a ceramic composite material made of precursor ceramic is used in the "Rapitherm" ceramic glow pencil candle developed by Robert Bosch GmbH, as is known from DE 100 20 329 AI and in particular also from DE 195 38 695 AI a particular partial pyrolysis, for example at 600 ° C. to 1400 ° C., in particular 1200 ° C. to 1300 ° C.
  • the starting material is a polysiloxane, ie a polymer made of Si, C, O and H, which is filled with fillers such as MoSi 2 , SiC, A1 2 0 3 , TiC, B 4 C, BN, TiN, mullite or Fe is mixed.
  • the electrical and physical property profile of the ceramic composite material of the glow pencil candle resulting after pyrolysis can be tailored to the respective requirements professional 1.
  • an oxygen-containing polysiloxane precursor as the starting material also enables particularly simple processing in air and thus the production of inexpensive products.
  • a pyrolysis product or ceramic composite made from a filled polysiloxane has very good properties
  • thermolysis process according to DE 195 38 695 AI compared to conventional manufacturing processes for ceramic composite materials such as sintering is that a much larger spectrum of possible fillers is available, since the pyrolysis used compared to conventional sintering Temperatures of typically more than 1600 ° C (especially in the case of Si 3 N 4 ) occur at much lower temperatures. In this respect, liquid or volatile fillers can still be used in the precursor pyrolysis process used even at conventional, comparatively high sintering temperatures, and phase reactions which otherwise occur are avoided even at higher temperatures.
  • polysiloxane resins as meltable thermosetting polymers and precursors that are soluble in organic solvents, allow simple and very homogeneous incorporation of fillers, for example by kneading or dissolving.
  • the influence of the matrix on the respective property should initially be as small as possible.
  • the matrix forms a coherent network in ceramic composite materials, such as those used for ceramic glow plugs, for example in the case of an insulating intermediate layer to be produced in a glow plug, the problem often arises from this material that the matrix unites after the layer has been manufactured has too low specific electrical resistance, or that the matrix or the entire composite material due to phase transformations,
  • the modification of the polymer or precursor material by boron for example in the form of boric acid esters and / or the addition of boron, for example as an additive in the form of one or more boron-containing fillers such as elemental boron, B 2 0 3 , BN or B 4 C, initially leads to an improved high-temperature resistance of the material with regard to phase separation and crystallization behavior. Furthermore, the durability of the material obtained is improved and the aging of the specific electrical resistance is reduced.
  • the use of boron has the effect that the resistance of the insulation layer of the glow plug can be stabilized in a range above 10,000 ohm cm, without any significant change in the mass composition of the insulation layer being necessary.
  • such an insulation layer resistance is a prerequisite for the manufacture of a glow pencil with a reduced shaft diameter.
  • Boron-containing ceramic composites are preferably produced, either by adding boron-containing fillers to a polysiloxane or by modifying the corresponding polymeric precursor with boron and subsequent pyrolysis in a gas atmosphere adapted to the application in the temperature range between 600 ° C. and 1400 ° C., in particular 1100 ° C to 1300 ° C have been obtained.
  • insulation materials and conductive compounds for glow plugs known from DE 195 38 695 A1 were incorporated during the preparation of boron-containing additives such as B 2 0 3 , and the pyrolysis was then carried out in the usual manner.
  • Si0 2 / B 2 ⁇ 3 mixture contains 80% by weight Si0 2 and 20% by weight boron or B 2 0 3 .
  • the masses were prepared by grinding in the corresponding starting powders, then sieving with a mesh size of 150 ⁇ m and then crosslinking and shaping using hot pressing. The samples were then pyrolyzed to compact samples at a heating rate of 25 K / h to a final temperature of 1300 ° C.
  • FIG. 1 shows a comparison of the shrinkage profile of the Si0 2 -containing sample and the Si0 2 / B 2 0 3 -containing sample, it being clearly recognizable that the addition of boron leads to a shrinkage which starts at comparatively low temperatures, which by formation of a borosilicate-like glass, which lowers the glass transition temperature, and / or by the action of boron as a sintering aid.
  • boron-containing insulation materials for a ceramic glow pencil candle are produced, the preparation of which, starting from appropriate ceramic starting mixtures, The next step is to use a conventional mixing and kneading process and then shape it using transfer molding.
  • composition of the various ceramic starting mixtures produced is in each case within the ranges 50 to 80 vol polysiloxane (with a
  • the boron-containing samples had a comparatively high length shrinkage ⁇ l / 1 of approx. -9.8%, a mass loss ⁇ m / m of approx. -4.7% and a specific electrical resistance of more than 10 6 ⁇ cm after pyrolysis and aging, while the boron-free reference samples showed only a shrinkage ⁇ l / 1 of approx. - 8.9%, a mass loss ⁇ m / m of approx. -4.5% and a specific electrical resistance of 10 4 ⁇ cm after pyrolysis and Showed outsourcing.
  • FIG. 3 shows the temperature-dependent specific electrical resistance of one of the insulation compositions explained above with an addition or proportion of 3% by weight boron in the form of elemental boron after 8 hours, 20 hours and 100 hours of exposure to air at 1300 ° C.
  • FIG. 4 shows a dilatometric measurement of the coefficient of thermal expansion as a function of the temperature for a sample with boron addition corresponding to FIG. 3, ie with 3% by weight boron, which was previously exposed to air at 1300 ° C., and corresponding measurements on samples without boron -Additive that was previously stored in air at 0 h, 12 h, 50 h or 150 h at 1300 ° C.
  • the measurements according to FIG. 4 were carried out at a heating rate of 5 K / min in an argon atmosphere.

Abstract

Disclosed is a ceramic composite material obtained by at least partially pyrolyzing an initial mixture or an initial body with a polymeric precursor material, the initial mixture or initial body containing 0.1 to 60 percent by mass of boron. Also disclosed is a method for producing such a ceramic composite material, according to which an initial mixture containing boron is subjected to at least partial pyrolysis with a polymeric precursor material. The invention also relates to a pencil-type glow plug containing the inventive ceramic composite material as an insulating and/or conducting layer.

Description

Keramischer Verbundwerkstoff. Verfahren zu dessen Herstellung und Gluhstiftkerze mit einem solchen VerbundwerkstoffCeramic composite. Process for its manufacture and glow pencil candle with such a composite material
Die Erfindung betrifft einen keramischen Verbundwerkstoff, ein Verfahren zu dessen Herstellung sowie eine Gluhstiftkerze mit einem solchen Verbundwerkstoff nach der Gattung der unabhängigen Ansprüche.The invention relates to a ceramic composite material, a method for its production and a glow pencil candle with such a composite material according to the preamble of the independent claims.
Stand der TechnikState of the art
Bei der Herstellung von keramischen Glühstiftkerzen, wie sie aus DE 198 52 785 AI o- der DE 100 20 329 AI bekannt sind, werden Keramik- Verbundwerkstoffe, insbesondere amorphe Si-0-C-Keramiken eingesetzt, die durch die insbesondere partielle Pyrolyse von elementorganischen Precursoren gewonnen werden. Die Vorteile des Precursor-Thermo- lyse- Verfahrens gegenüber konventionellen Herstellungsverfahren für Keramiken, d.h. Sintern, liegt in der wesentlich niedrigeren Prozesstemperatur und der einfachen Verar- beitbarkeit und Formbarkeit von Polysiloxanharzen. Diese Vorgehensweise ist ausführlich in DE 195 38 695 AI beschrieben.In the production of ceramic glow plugs, as are known from DE 198 52 785 AI or DE 100 20 329 AI, ceramic composites, in particular amorphous Si-0-C ceramics, are used which, in particular due to the partial pyrolysis of organic elements Precursors are won. The advantages of the precursor thermolysis process compared to conventional manufacturing processes for ceramics, i.e. Sintering lies in the much lower process temperature and the easy processability and formability of polysiloxane resins. This procedure is described in detail in DE 195 38 695 AI.
Die Herstellung von Formkörpern aus diesen Keramik- Verbundwerkstoffen ist weiter nur unter Verwendung von zusätzlichen Füllstoffen möglich, da sonst Schwindungsrisse und Poren während der Pyrolyse auftreten. Dazu ist in EP 0412 428 Bl bereits vorgeschlagen worden, über ausgewählte Füllstoffe in einem Ausgangskomposit die Eigenschaften des erhaltenen Keramik-Verbundwerkstoffes wie dessen Wärmeausdehnungskoeffizient, Wärmeleitfähigkeit oder spezifischer elektrischer Widerstand präzise einzustellen. Insbesondere wird dort vorgeschlagen, reaktive Füller einzusetzen, um eine bessere Anbindung der Füllstoffe an die Matrix zu erreichen, aber auch inerte Füllstoffe zu verwenden. Aufgabe der vorliegenden Erfindung war die Bereitstellung eines keramischen Verbundwerkstoffes, der in einer Gluhstiftkerze einsetzbar ist, mit einem insbesondere erhöhten spezifischen elektrischen Widerstand, der möglichst unabhängig von zusätzlich in dem Verbundwerkstoff eingesetzten Füllstoffen sein sollte, sowie einer verbesserten Dauerhaltbarkeit. Daneben soll der keramische Verbundwerkstoff keine oder eine möglichst geringe Alterung der Funktionseigenschaften beim Einsatz in einer Gluhstiftkerze, insbesondere hinsichtlich Aufheizzeit und Glühtemperatur, aufweisen.The production of moldings from these ceramic composites is only possible using additional fillers, otherwise shrinkage cracks and pores will occur during pyrolysis. For this purpose, it has already been proposed in EP 0412 428 B1 to precisely set the properties of the ceramic composite material obtained, such as its coefficient of thermal expansion, thermal conductivity or specific electrical resistance, using selected fillers in an initial composite. In particular, it is proposed to use reactive fillers to achieve a better connection of the fillers to the matrix, but also to use inert fillers. The object of the present invention was to provide a ceramic composite material which can be used in a glow plug, with a particularly increased specific electrical resistance, which should be as independent as possible of fillers additionally used in the composite material, and improved durability. In addition, the ceramic composite material should have no or as little aging as possible of the functional properties when used in a glow pencil candle, in particular with regard to the heating-up time and glow temperature.
Vorteile der ErfindungAdvantages of the invention
Durch den Einbauch von 0,1 Masse% bis 60 Masse% Bor, vorzugsweise 0,5 Masse% bis 10 Masse% Bor, in eine Polymermatrix und/oder durch die Verwendung entsprechender, vorzugsweise geringer Mengen borhaltiger Füllstoffe bei der Herstellung von Keramik- Verbundwerkstoffen, insbesondere amorpher Si-0-C-Keramik- Verbundwerkstoffen, er- reicht man eine Hemmung der Phasenseparation in der Si-O-C-Matrix und damit eineBy incorporating 0.1% by mass to 60% by mass of boron, preferably 0.5% by mass to 10% by mass of boron, in a polymer matrix and / or by using appropriate, preferably small amounts of boron-containing fillers in the production of ceramic composite materials , in particular amorphous Si-0-C ceramic composites, one achieves an inhibition of the phase separation in the Si-OC matrix and thus one
Hemmung der Bildung von freiem Kohlenstoff, was zu einer Erhöhung des spezifischen elektrischen Widerstands des Keramik- Verbundwerkstoffes zunächst unabhängig von zusätzlich verwendeten Füllstoffen führt. Insbesondere wurde bei einer auf diese Weise hergestellten Isolationsschicht für eine Gluhstiftkerze auch nach längerer Auslagerungs- zeit, beispielsweise 100 h, keine relevante Alterung des spezifischen elektrischen Widerstands festgestellt.Inhibition of the formation of free carbon, which initially leads to an increase in the specific electrical resistance of the ceramic composite material, regardless of any additional fillers used. In particular, in the case of an insulation layer for a glow pencil candle produced in this way, no relevant aging of the specific electrical resistance was found even after a long aging period, for example 100 hours.
Weiter wird eine verbesserte Verglasung in dem Keramik- Verbundwerkstoff erreicht, was zumindest teilweise der Bildung borhaltiger Gläser oder entsprechender glasartiger Bereiche in dem Verbundwerkstoff mit erniedrigter Glasübergangstemperatur zuzuschreiben ist, und was die Dauerhaltbarkeit insbesondere damit hergestellter Glühstiftkerzen erhöht.Furthermore, improved glazing in the ceramic composite material is achieved, which is at least partially attributable to the formation of boron-containing glasses or corresponding glass-like areas in the composite material with a lower glass transition temperature, and which increases the durability, in particular glow plugs produced therewith.
Insbesondere bildet sich nunmehr vielfach eine dichte Glasschicht in und oder an der O- berfläche des Verbundwerkstoffes aus, und es unterbleibt auch nach längeren Auslagerungszeiten, beispielsweise 100 h, eine Oxidation im Inneren des eingesetzten Materials, d.h. es bildet sich dort vor allem kein M0O3, Mθ5Si3 oder kristallines Si02, was Selbstausheilungsprozesse in dem Werkstoff bei Rissbildung erleichtert und dessen Festigkeit insgesamt erhöht. Daneben wird bereits durch die Zugabe von vergleichsweise geringen Mengen an Bor bei 1300°C über 100 h oder bei 1350°C über 8 h an Luft eine einsetzende Kristallisation einer keramischen Matrix auf Basis von Si-O-C -Bildung unter Bildung von Cristobalit unterdrückt, was ebenfalls die Dauerhaltbarkeit und Thermowechselbeständigkeit des Materials erhöht.In particular, a dense glass layer is now often formed in and or on the surface of the composite material, and there is no oxidation in the interior of the material used, even after longer aging times, for example 100 h, ie no M0O 3 is formed there , Mθ 5 Si 3 or crystalline Si0 2 , which facilitates self-healing processes in the material when cracks form and increases its strength overall. In addition, the onset of crystallization of a ceramic matrix based on Si-OC formation with the formation of cristobalite is suppressed by the addition of comparatively small amounts of boron at 1300 ° C for 100 h or at 1350 ° C for 8 h, which the durability and thermal shock resistance of the material are also increased.
Zusammenfassend wird durch das eingesetzte Bor eine Alterung des spezifischen elektrischen Widerstands in dem keramischen Verbundwerkstoff unterdrückt und eine Verbesserung von dessen Funktionseigenschaften und damit auch einer mit diesem hergestellten Gluhstiftkerze, vor allem hinsichtlich Aufheizzeit und Glühtemperatur, erreicht.In summary, aging of the specific electrical resistance in the ceramic composite material is suppressed by the boron used and an improvement in its functional properties and thus also in a glow pencil candle produced therewith, especially with regard to the heating-up time and glow temperature, is achieved.
Im Fall der Verwendung des herstellenden Verbundwerkstoffes in einer Gluhstiftkerze ist überdies vorteilhaft, dass dadurch eine Erhöhung des spezifischen elektrischen Widerstandes der Isolationsschicht der Gluhstiftkerze, eine Unterdrückung einer unerwünschten Alterung des Widerstands der Isolationsschicht und/oder der Leitschicht der Gluhstiftkerze, und eine engere Widerstandsverteilung in der Leitschicht erreicht wird, was unter anderem zu einem verringerten Aufwand in der Fertigung, bei der Qualitätskontrolle und der Widerstandsklassifϊzierung führt. Zudem wird es nun auch möglich, die Isolationsschicht der Gluhstiftkerze insgesamt dünner zu machen.If the manufacturing composite is used in a glow plug, it is also advantageous that this increases the specific electrical resistance of the insulation layer of the glow plug, suppresses undesired aging of the resistance of the insulation layer and / or the conductive layer of the glow plug, and narrows the resistance distribution in the Control layer is achieved, which among other things leads to a reduced effort in production, quality control and resistance classification. In addition, it is now also possible to make the insulation layer of the glow pencil candle thinner overall.
Vorteilhafte Weiterbildungen der Erfindung ergeben sich aus den in den Unteransprüchen genannten Maßnahmen.Advantageous developments of the invention result from the measures mentioned in the subclaims.
Zeichnungendrawings
Die Erfindung wird anhand der Zeichnungen und der nachfolgenden Beschreibung näher erläutert. Es zeigt Figur 1 den Unterschied in der prozentualen Pyrolyseschwindung eines borhaltigen keramischen Verbundwerkstoffes im Vergleich zu einem borfreien als Funktion der Pyrolysetemperatur, Figur 2 ein Raman-Spektrum des borhaltigen und des borfreien Verbundwerkstoffes gemäß Figur 1 bei einer Temperatur von 1325°C, Figur 3 den spezifischen elektrischen Widerstand eines borhaltigen Verbundwerkstoffes als Funktion der Auslagerungszeit an Luft bei 1300°C Auslagerungstemperatur, und Figur 4 Dilatometermessungen zur Ermittlung des thermischen Ausdehnungskoeffizienten an einem borhaltigen Verbundwerkstoff im Vergleich zu einem borfreien als Funktion der Auslagerungszeit an Luft bei 1300°C Auslagerungstemperatur. AusführungsbeispieleThe invention is explained in more detail with reference to the drawings and the description below. 1 shows the difference in the percentage pyrolysis shrinkage of a boron-containing ceramic composite compared to a boron-free one as a function of the pyrolysis temperature, FIG. 2 shows a Raman spectrum of the boron-containing and the boron-free composite material according to FIG. 1 at a temperature of 1325 ° C., FIG. 3 shows the specific electrical resistance of a boron-containing composite material as a function of the exposure time in air at 1300 ° C exposure temperature, and FIG. 4 dilatometer measurements to determine the thermal expansion coefficient of a boron-containing composite material compared to a boron-free one as a function of the exposure time in air at 1300 ° C exposure temperature. embodiments
Bei der von der Robert Bosch GmbH entwickelten keramischen Gluhstiftkerze „Ra- pitherm", wie sie aus DE 100 20 329 AI und insbesondere auch aus DE 195 38 695 AI bekannt ist, wird ein Keramik- Verbund-Werkstoff aus Precursor-Keramik eingesetzt, der einer insbesondere partiellen Pyrolyse beispielsweise bei 600°C bis 1400°C, insbesondere 1200°C bis 1300°C unterzogen wurde. Das Ausgangsmaterial ist dabei ein Polysiloxan, d.h. ein Polymer aus Si, C, O und H, das mit Füllstoffen wie beispielsweise MoSi2, SiC, A1203, TiC, B4C, BN, TiN, Mullit oder Fe vermischt wird.A ceramic composite material made of precursor ceramic is used in the "Rapitherm" ceramic glow pencil candle developed by Robert Bosch GmbH, as is known from DE 100 20 329 AI and in particular also from DE 195 38 695 AI a particular partial pyrolysis, for example at 600 ° C. to 1400 ° C., in particular 1200 ° C. to 1300 ° C. The starting material is a polysiloxane, ie a polymer made of Si, C, O and H, which is filled with fillers such as MoSi 2 , SiC, A1 2 0 3 , TiC, B 4 C, BN, TiN, mullite or Fe is mixed.
Durch die Wahl der Füllstoffe kann, wie in DE 195 38 695 AI ausführlich beschrieben, das elektrische und physikalische Eigenschaftsprofil des nach der Pyrolyse resultierenden Keramik-Verbund-Werkstoffes der Gluhstiftkerze auf das jeweilige Anforderungsprofi 1 zugeschnitten werden.By choosing the fillers, as described in detail in DE 195 38 695 AI, the electrical and physical property profile of the ceramic composite material of the glow pencil candle resulting after pyrolysis can be tailored to the respective requirements professional 1.
Die Verwendung eines sauerstoffhaltigen Polysiloxan-Precursors als Ausgangsmaterial ermöglicht zudem eine besonders einfache Verarbeitung unter Luft und damit die Herstellung kostengünstiger Produkte. Daneben besitzt ein derartiges Pyrolyse-Produkt bzw. ein derartiger keramischer Verbundwerkstoff aus einem gefüllten Polysiloxan sehr guteThe use of an oxygen-containing polysiloxane precursor as the starting material also enables particularly simple processing in air and thus the production of inexpensive products. In addition, such a pyrolysis product or ceramic composite made from a filled polysiloxane has very good properties
Festigkeitseigenschaften, eine hohe chemische Stabilität gegenüber Oxidation oder Korrosion und ist gesundheitlich unbedenklich.Strength properties, a high chemical stability against oxidation or corrosion and is harmless to health.
Einer der großen Vorteile des Precursor-Thermolyse-Verfahrens gemäß DE 195 38 695 AI gegenüber konventionellen Herstellungsverfahren für Keramik- Verbund-Werkstoffe wie Sintern liegt darin, dass ein wesentlich größeres Spektrum an möglichen Füllstoffen zur Verfügung steht, da die eingesetzte Pyrolyse gegenüber üblichem Sintern bei Temperaturen von typischerweise mehr als 1600°C (insbesondere im Fall von Si3N4) bei wesentlich niedrigeren Temperaturen abläuft. Insofern können auch bei üblichen, ver- gleichsweise hohen Sintertemperaturen flüssige oder flüchtige Füllstoffe bei dem eingesetzten Precursor-Pyrolyse-Prozess noch verwendet werden, und es werden auch bei höheren Temperaturen ansonsten auftretende Phasenreaktionen vermieden. Schließlich erlauben Polysiloxanharze als schmelzbare duroplastische und in organischen Lösungsmitteln lösliche Polymere bzw. Precursoren ein einfaches und sehr homogenes Einarbeiten von Füllstoffen, beispielsweise mittels Kneten oder Lösen. Um die Einstellung einer gewünschten Eigenschaft des erzeugten Werkstoffes über den Füllstoff möglichst einfach und effektiv zu gestalten, sollte der Einfluss der Matrix auf die jeweilige Eigenschaft zunächst generell möglichst gering sein. Da andererseits die Matrix in keramischen Verbundwerkstoffen, wie sie für keramische Glühstiftkerzen eingesetzt werden, ein zusammenhängendes Netzwerk bildet, ergibt sich beispielsweise im Fall einer herzustellenden isolierenden Zwischenschicht in einer Gluhstiftkerze aus diesem Material vielfach das Problem, dass die Matrix nach Abschluss des Herstellungsprozesses der Schicht einen zu niedrigen spezifischen elektrischen Widerstand besitzt, oder dass die Matrix oder der gesamte Verbundwerkstoff aufgrund von Phasenumwandlungen,One of the great advantages of the precursor thermolysis process according to DE 195 38 695 AI compared to conventional manufacturing processes for ceramic composite materials such as sintering is that a much larger spectrum of possible fillers is available, since the pyrolysis used compared to conventional sintering Temperatures of typically more than 1600 ° C (especially in the case of Si 3 N 4 ) occur at much lower temperatures. In this respect, liquid or volatile fillers can still be used in the precursor pyrolysis process used even at conventional, comparatively high sintering temperatures, and phase reactions which otherwise occur are avoided even at higher temperatures. Finally, polysiloxane resins, as meltable thermosetting polymers and precursors that are soluble in organic solvents, allow simple and very homogeneous incorporation of fillers, for example by kneading or dissolving. In order to make the setting of a desired property of the material produced via the filler as simple and effective as possible, the influence of the matrix on the respective property should initially be as small as possible. On the other hand, since the matrix forms a coherent network in ceramic composite materials, such as those used for ceramic glow plugs, for example in the case of an insulating intermediate layer to be produced in a glow plug, the problem often arises from this material that the matrix unites after the layer has been manufactured has too low specific electrical resistance, or that the matrix or the entire composite material due to phase transformations,
Kristallisationseffekten und Oxidationsprozessen über der Herstellung oder nachfolgend im Betrieb insbesondere allmählich an Hochtemperaturfestigkeit und Thermoschockbe- ständigkeit verliert.Crystallization effects and oxidation processes during manufacture or subsequently in operation gradually lose their high-temperature strength and thermal shock resistance.
Wesentlich für die Erfindung ist die Verwendung von Bor in einer Mischung oder einemThe use of boron in a mixture or in an is essential for the invention
Ausgangskörper gemäß DE 195 38 695 AI bzw. der Zusatz von Bor zu einem Polymermaterial oder Precursormaterial wie einem Polysiloxanharz und/oder die Modifizierung des Polymer- oder Precursormaterials durch Bor, wobei daraus dann über ein Precursor- Thermolyse-Verfahren im Rahmen insbesondere einer partiellen Pyrolyse ein Keramik- Verbundwerkstoff, insbesondere eine amorphe Si-O-C-Keramik Matrix mit oder ohneStarting body according to DE 195 38 695 AI or the addition of boron to a polymer material or precursor material such as a polysiloxane resin and / or the modification of the polymer or precursor material by boron, using a precursor thermolysis process in particular partial pyrolysis a ceramic composite material, in particular an amorphous Si-OC ceramic matrix with or without
Füllstoff, hergestellt wird.Filler, is produced.
Die Modifizierung des Polymer- bzw. Precursormaterials durch Bor, beispielsweise in Form von Borsäureestern und/oder der Zusatz von Bor, beispielsweise als Additiv in Form eines oder mehrerer borhaltiger Füllstoffe wie elementares Bor, B203, BN oder B4C führt zunächst zu einer verbesserten Hochtemperaturbeständigkeit des Materials bezüglich Phasenseparation und Kristallisationsverhalten. Weiter wird die Dauerhaltbarkeit des erhaltenen Werkstoffes verbessert und die Alterung des spezifischen elektrischen Widerstands verringert.The modification of the polymer or precursor material by boron, for example in the form of boric acid esters and / or the addition of boron, for example as an additive in the form of one or more boron-containing fillers such as elemental boron, B 2 0 3 , BN or B 4 C, initially leads to an improved high-temperature resistance of the material with regard to phase separation and crystallization behavior. Furthermore, the durability of the material obtained is improved and the aging of the specific electrical resistance is reduced.
Daneben wurde überraschend festgestellt, dass der erläuterte Einsatz von Bor zu einer signifikanten und erwünschten Erhöhung des elektrischen Widerstands eines üblichen, beispielsweise aus DE 195 38 695 AI bekannten keramischen Verbundwerkstoffes führt, wie er in Glühstiftkerzen als Isolierschicht eingesetzt wird. So wurde beobachtet, dass ein Zusatz von Bor bei Raumtemperatur eine Steigerung des spezifischen elektrischen Wi- derstandes der Isolationsschicht einer solchen aus einem Keramik- Verbundwerkstoff über ein Precursor-Thermoylse-Verfahren hergestellten Gluhstiftkerze um einen Faktor 1000 bewirkt.In addition, it was surprisingly found that the use of boron as explained leads to a significant and desired increase in the electrical resistance of a conventional ceramic composite material, for example known from DE 195 38 695 AI, as is used as an insulating layer in glow plugs. It was observed, for example, that adding boron at room temperature increases the specific electrical the effect of the insulation layer of such a glow pencil candle produced from a ceramic composite material by means of a precursor thermo-lysis process by a factor of 1000.
Insbesondere bewirkt der Einsatz von Bor, dass sich der Widerstand der Isolationsschicht der Gluhstiftkerze in einem Bereich oberhalb von 10000 Ohm cm stabilisieren lässt, ohne dass eine nennenswerte Änderung der Massenzusammensetzung der Isolationsschicht erforderlich wäre. Andererseits ist ein derartiger Isolationsschichtwiderstand Voraussetzung für die Herstellung einer Gluhstiftkerze mit verringertem Schaftdurchmesser.In particular, the use of boron has the effect that the resistance of the insulation layer of the glow plug can be stabilized in a range above 10,000 ohm cm, without any significant change in the mass composition of the insulation layer being necessary. On the other hand, such an insulation layer resistance is a prerequisite for the manufacture of a glow pencil with a reduced shaft diameter.
Bevorzugt werden borhaltige Keramik- Verbundwerkstoffe erzeugt, die entweder durch Zusatz borhaltiger Füllstoffe zu einem Polysiloxan oder durch Modifizierung der entsprechenden polymeren Vorstufe mit Bor und ein anschließendes Pyrolysieren in einer auf den Anwendungsfall angepassten Gasatmosphäre im Temperaturbereich zwischen 600°C und 1400°C, insbesondere 1100°C bis 1300°C erhalten worden sind. Insbesondere wurden in beispielsweise aus DE 195 38 695 AI bekannte Isolationsmassen und Leitmassen für Glühstiftkerzen während der Aufbereitung borhaltige Zusätze wie B203 eingearbeitet, und danach die Pyrolyse in der üblichen Weise durchgeführt.Boron-containing ceramic composites are preferably produced, either by adding boron-containing fillers to a polysiloxane or by modifying the corresponding polymeric precursor with boron and subsequent pyrolysis in a gas atmosphere adapted to the application in the temperature range between 600 ° C. and 1400 ° C., in particular 1100 ° C to 1300 ° C have been obtained. In particular, insulation materials and conductive compounds for glow plugs known from DE 195 38 695 A1 were incorporated during the preparation of boron-containing additives such as B 2 0 3 , and the pyrolysis was then carried out in the usual manner.
Beispiel 1:Example 1:
Es werden zwei Massen beispielsweise gemäß DE 195 38 695 AI mit gleichem Volumenanteil an Füllstoffen hergestellt, die einerseits 75 Vol% Polymer (Polysiloxanharz) und 25 Vol% Si02 und andererseits 75 Vol% Polymer (Polysiloxanharz) und 35 Vol% eines Si02/B2θ3-Gemisches enthalten. Das Si02/B2θ3-Gemisch enthält 80 Gew% Si02 und 20 Gew% Bor bzw. B203.There are two masses, for example according to DE 195 38 695 AI with the same volume fraction of fillers, which on the one hand 75 vol% polymer (polysiloxane resin) and 25 vol% Si0 2 and on the other hand 75 vol% polymer (polysiloxane resin) and 35 vol% of a Si0 2 / B 2 θ 3 mixture included. The Si0 2 / B 2 θ 3 mixture contains 80% by weight Si0 2 and 20% by weight boron or B 2 0 3 .
Die Aufbereitung der Massen erfolgte jeweils über ein Einmahlen der entsprechenden Ausgangspulver, anschließendes Sieben mit einer Maschenweite von 150 μm und nach- folgendes Vernetzen und Formgeben über ein Warmpressen. Danach wurden die Proben mit einer Aufheizrate von 25 K/h auf eine Endtemperatur von 1300°C zu kompakten Proben pyrolysiert.The masses were prepared by grinding in the corresponding starting powders, then sieving with a mesh size of 150 μm and then crosslinking and shaping using hot pressing. The samples were then pyrolyzed to compact samples at a heating rate of 25 K / h to a final temperature of 1300 ° C.
Bei der Pyrolyse auf eine Endtemperatur von 1300°C zeigte diejenige Probe, die kein Bor enthielt, eine Längenschwindung Δl/1 von -16,5 %, einen Massenverlust Δm/m von -On pyrolysis to a final temperature of 1300 ° C, the sample that did not contain boron showed a lengthwise shrinkage Δl / 1 of -16.5%, a mass loss Δm / m of -
17,0 % und einen spezifischen elektrischen Widerstand von ca. 105 Ωcm, während sich % und einen spezifischen elektrischen Widerstand von ca. 105 Ωcm, während sich bei der borhaltigen Probe eine Längenschwindung Δl/1 von -15,3 %, ein Massenverlust Δm m von -18,0 % und ein spezifischer elektrischer Widerstand von mehr als 106 Ωcm ergab.17.0% and a specific electrical resistance of approximately 10 5 Ωcm, while % and a specific electrical resistance of approx. 10 5 Ωcm, while in the boron-containing sample there is a longitudinal shrinkage Δl / 1 of -15.3%, a mass loss Δm m of -18.0% and a specific electrical resistance of more than 10 6 Ωcm resulted.
Um die unterschiedlichen Stadien der Keramisierung des Materials zu untersuchen, wurde die Pyrolyse im Rahmen einer Versuchsreihe bei verschiedenen Temperaturen abgebrochen.In order to investigate the different stages of the ceramization of the material, the pyrolysis was stopped in the course of a series of tests at different temperatures.
Die Figur 1 zeigt dazu einen Vergleich des Schwindungsverlaufes der Si02-haltigen Probe und der Si02/B203-haltigen Probe, wobei deutlich erkennbar ist, dass die Zugabe von Bor zu einer bereits bei vergleichsweise geringen Temperaturen einsetzenden Schwindung führt, was durch Bildung eines borosilikatartigen Glases, welches die Glasübergangstemperatur herabsetzt, und/oder durch die Wirkung von Bor als Sinterhilfsmittel hervorgerufen sein könnte.FIG. 1 shows a comparison of the shrinkage profile of the Si0 2 -containing sample and the Si0 2 / B 2 0 3 -containing sample, it being clearly recognizable that the addition of boron leads to a shrinkage which starts at comparatively low temperatures, which by formation of a borosilicate-like glass, which lowers the glass transition temperature, and / or by the action of boron as a sintering aid.
Durch in Figur 2 exemplarisch an Proben, die bei 1325°C pyrolysiert wurden, dargestellte Raman-Untersuchungen der Kohlenstoff-Banden konnte weiter nachgewiesen werden, dass die Phasenseparation bei der borhaltigen Probe gegenüber der borfreien zunächst gehemmt ist und erst bei wesentlich höheren Temperaturen auftritt.By way of example of Raman investigations of the carbon bands shown in FIG. 2 on samples pyrolyzed at 1325 ° C., it was further possible to demonstrate that the phase separation in the boron-containing sample is initially inhibited compared to the boron-free sample and only occurs at significantly higher temperatures.
Da die Separation von Kohlenstoff in den Proben bzw. hergestellten keramischen Verbundwerkstoffe als Hauptgrund für deren insbesondere allmähliche Verringerung des spezifischen elektrischen Widerstands angesehen wird, lässt sich durch die Messung des spezifischen elektrischen Widerstands eine Korrelation zu den Raman-Untersuchungen gemäß Figur 2 herstellen. So konnte gezeigt werden, dass diejenigen Proben, die im Ra- man-Spektrum ausgeprägte Phasenseparationen zeigten, vergleichsweise niedrigere spezifische elektrische Widerstände aufweisen.Since the separation of carbon in the samples or ceramic composites produced is regarded as the main reason for their gradual reduction in the specific electrical resistance in particular, the measurement of the specific electrical resistance enables a correlation to be established with the Raman investigations according to FIG. 2. It could be shown that those samples that showed pronounced phase separations in the Raman spectrum have comparatively lower specific electrical resistances.
Beispiel 2:Example 2:
Es werden, erneut ausgehend von der Lehre von DE 195 38 695 AI oder auch DE 100 20 329 AI, borhaltige Isolationsmassen für eine keramische Gluhstiftkerze hergestellt, deren Aufbereitung, ausgehend von entsprechenden keramischen Ausgangsmischungen, zu- nächst über einen üblichen Misch- und Knetprozess und deren Formgebung danach mittels Transfermolding erfolgt.Again based on the teaching of DE 195 38 695 AI or also DE 100 20 329 AI, boron-containing insulation materials for a ceramic glow pencil candle are produced, the preparation of which, starting from appropriate ceramic starting mixtures, The next step is to use a conventional mixing and kneading process and then shape it using transfer molding.
Die Zusammensetzung der hergestellten verschiedenen keramischen Ausgangsmischun- gen liegt dabei jeweils innerhalb der Bereiche 50 bis 80 Vol Polysiloxan (mit einemThe composition of the various ceramic starting mixtures produced is in each case within the ranges 50 to 80 vol polysiloxane (with a
Zusatz von jeweils 1 Masse% Zirkonacetylacetonat, das als Katalysator zur Vernetzung des Polysiloxans z.B. bei einem Warmpressen dient), 0 bis 10 Vol% SiC als Füllstoff, 0 bis 20 Vol% A1203 als Füllstoff, 0 bis 20 Mol% MoSi2 als Füllstoff und jeweils 3 Gew.% Bor, das in Form von B203 eingesetzt wurde. Daneben wurde zu jeder der Proben mit unterschiedlicher Zusammensetzung innerhalb dieser Bereiche eine entsprechende borfreie Referenzprobe hergestellt.Addition of 1% by mass of zirconium acetylacetonate, which serves as a catalyst for crosslinking the polysiloxane, e.g. in hot pressing), 0 to 10% by volume SiC as filler, 0 to 20% by volume A1 2 0 3 as filler, 0 to 20 mol% MoSi 2 as filler and in each case 3% by weight of boron, which was used in the form of B 2 0 3 . In addition, a corresponding boron-free reference sample was produced for each of the samples with different compositions within these ranges.
Die Pyrolyse nach der Formgebung erfolgte jeweils bei Temperaturen von 1300°C unter Argondurchfluss in einem Astro Graphit-Ofen. Der Füllgrad des Ofens bezogen auf das Retortenvolumen lag jeweils bei 18%. Abschließend wurden die hergestellten Proben bzw. keramischen Verbundwerkstoffe in einem Nabertherm Ofen über 13 h bei 1300°C an Luft ausgelagert.The pyrolysis after the shaping was carried out in each case at temperatures of 1300 ° C. under argon flow in an astro graphite furnace. The degree of filling of the furnace based on the retort volume was 18% in each case. Finally, the samples or ceramic composites produced were stored in air in a Nabertherm oven for 13 h at 1300 ° C.
Insgesamt ergab sich dabei, dass die borhaltigen Proben eine vergleichsweise hohe Län- genschwindung Δl/1 von ca -9,8 %, einen Massenverlust Δm/m von ca, -4,7 % und einen spezifischen elektrischen Widerstand von mehr als 106 Ωcm nach Pyrolyse und Auslagerung zeigten, während die borfreien Referenzproben nur eine Schwindung Δl/1 von ca. - 8,9 %, ein Massenverlust Δm/m von ca. -4,5 % und einen spezifischen elektrischen Widerstand von 104 Ωcm nach Pyrolyse und Auslagerung zeigten.Overall, it was found that the boron-containing samples had a comparatively high length shrinkage Δl / 1 of approx. -9.8%, a mass loss Δm / m of approx. -4.7% and a specific electrical resistance of more than 10 6 Ωcm after pyrolysis and aging, while the boron-free reference samples showed only a shrinkage Δl / 1 of approx. - 8.9%, a mass loss Δm / m of approx. -4.5% and a specific electrical resistance of 10 4 Ωcm after pyrolysis and Showed outsourcing.
Um die Verbesserung der Widerstandsalterung der Isolationsschicht durch Zugabe von Bor als Additiv nachzuweisen, wurden weiter temperaturabhängige Messungen des spezifischen elektrischen Widerstands nach verschiedenen Auslagerungszeiten durchgeführt, die exemplarisch in Figur 3 dargestellt sind. Im Einzelnen zeigt Figur 3 den temperatur- abhängigen spezifischen elektrischen Widerstand einer der vorstehend erläuterten Isolationsmassen mit einem Zusatz bzw. Anteil von 3 Gew% Bor in Form von elementarem Bor nach 8 h, 20 h und 100 h Auslagerungszeit bei 1300°C an Luft.In order to demonstrate the improvement in the resistance aging of the insulation layer by adding boron as an additive, further temperature-dependent measurements of the specific electrical resistance were carried out after various aging times, which are shown by way of example in FIG. 3. In detail, FIG. 3 shows the temperature-dependent specific electrical resistance of one of the insulation compositions explained above with an addition or proportion of 3% by weight boron in the form of elemental boron after 8 hours, 20 hours and 100 hours of exposure to air at 1300 ° C.
Schließlich wurde an diesen Proben die Kristallisation bezüglich der Cristobalitent- wicklung als Funktion der Auslagerungszeigt bei 1300°C an Luft untersucht. Dazu ist in Figur 4 eine dilatometrische Messung des thermischen Ausdehnungskoeffizienten als Funktion der Temperatur für eine Probe mit Bor-Zusatz entsprechend Figur 3, d.h. mit 3 Gew% Bor, wiedergeben, die zuvor bei 1300°C an Luft ausgelagert wurde, sowie entsprechende Messungen an Proben ohne Bor-Zusatz, die zuvor bei 0 h, 12 h, 50 h oder 150 h bei 1300°C an Luft ausgelagert wurden. Die Messungen gemäß Figur 4 erfolgten mit einer Aufheizrate von 5 K/min in Argon-Atmosphäre.Finally, the crystallization with respect to the cristobalite development as a function of the exposure at 1300 ° C in air was investigated on these samples. This is in FIG. 4 shows a dilatometric measurement of the coefficient of thermal expansion as a function of the temperature for a sample with boron addition corresponding to FIG. 3, ie with 3% by weight boron, which was previously exposed to air at 1300 ° C., and corresponding measurements on samples without boron -Additive that was previously stored in air at 0 h, 12 h, 50 h or 150 h at 1300 ° C. The measurements according to FIG. 4 were carried out at a heating rate of 5 K / min in an argon atmosphere.
Man erkennt deutlich, dass die Auslagerung bei der borhaltigen Probe keinen Einfluss auf das thermische Ausdehnungsverhalten hat, während bei der borfreien Probe bereits nach 12 h und vor allem nach 50 h Auslagerungszeit im Temperaturbereich von ca. 220°C gravierende Veränderungen auftreten, was einer einsetzenden Kristallisation unter Bildung von Cristobalit zugeschrieben wird. It can clearly be seen that the aging in the boron-containing sample has no influence on the thermal expansion behavior, while in the boron-free sample, serious changes occur after just 12 hours and especially after 50 hours of aging in the temperature range of approx. 220 ° C, which is an onset Crystallization with formation of cristobalite is attributed.

Claims

Patentansprüche claims
1. Keramischer Verbundwerkstoff, der durch zumindest partielle Pyrolyse einer Ausgangsmischung oder eines Ausgangskörpers mit polymeren Precursormaterials erhältlich ist, dadurch gekennzeichnet, dass in der Ausgangsmischung oder dem Ausgangskörper Bor in einem Anteil von 0,1 bis 60 Masse% enthalten ist.1. Ceramic composite material which is obtainable by at least partial pyrolysis of a starting mixture or a starting body with polymeric precursor material, characterized in that boron is contained in a proportion of 0.1 to 60% by mass in the starting mixture or the starting body.
2. Keramischer Verbundwerkstoff nach Anspruch 1, dadurch gekennzeichnet, dass er eine Matrix aufweist, die zumindest weitgehend aus einer insbesondere amorphen Si-O- C-Keramik besteht.2. Ceramic composite material according to claim 1, characterized in that it has a matrix which consists at least largely of a particularly amorphous Si-O-C ceramic.
3. Keramischer Verbundwerkstoff nach Anspruch 1, dadurch gekennzeichnet, dass mindestens ein Füllstoff, insbesondere Al2θ3, Si02, Ti02, Zr02, SiC oder MoSi2, zugesetzt ist.3. Ceramic composite material according to claim 1, characterized in that at least one filler, in particular Al 2 θ 3 , Si0 2 , Ti0 2 , Zr0 2 , SiC or MoSi 2 , is added.
4. Keramischer Verbundwerkstoff nach Anspruch 1, dadurch gekennzeichnet, dass in die Ausgangsmischung oder den Ausgangskörper ein Polysiloxan-Precursor eingesetzt ist.4. Ceramic composite material according to claim 1, characterized in that a polysiloxane precursor is used in the starting mixture or the starting body.
5. Keramischer Verbundwerkstoff nach Anspruch 1, dadurch gekennzeichnet, dass in der Ausgangsmischung oder dem Ausgangskörper Bor in einem Anteil von 0,5 bis 10 Masse% enthalten ist.5. Ceramic composite material according to claim 1, characterized in that boron is contained in a proportion of 0.5 to 10% by mass in the starting mixture or the starting body.
6. Keramischer Verbundwerkstoff nach Anspruch 1, dadurch gekennzeichnet, dass ein durch Bor modifiziertes Polymer- bzw. Precursormaterial, insbesondere Polysiloxan und/oder ein Borzusatz in Form eines borhaltigen Füllstoffes wie B203, elementares Bor, B4C oder BN in die Ausgangsmischung eingesetzt oder dem Ausgangskörper zugesetzt ist. 6. Ceramic composite according to claim 1, characterized in that a boron-modified polymer or precursor material, in particular polysiloxane and / or a boron additive in the form of a boron-containing filler such as B 2 0 3 , elemental boron, B 4 C or BN in the Starting mixture is used or added to the starting body.
7. Gluhstiftkerze mit einem keramischen Verbundwerkstoff nach einem der vorangehenden Ansprüche als Isolierschicht und/oder Leitschicht.7. glow pencil candle with a ceramic composite material according to one of the preceding claims as an insulating layer and / or conductive layer.
8. Verfahren zur Herstellung eines keramischen Verbundwerkstoffes nach einem der Ansprüche 1 bis 6, wobei eine borhaltige Ausgangsmischung mit einem polymeren Precursormaterial einer zumindest partiellen Pyrolyse unterzogen wird. 8. A method for producing a ceramic composite material according to one of claims 1 to 6, wherein a boron-containing starting mixture with a polymeric precursor material is subjected to an at least partial pyrolysis.
EP02794999A 2002-01-30 2002-12-16 Ceramic composite material, method for the production thereof, and pencil-type glow plug containing such a composite material Withdrawn EP1472197A1 (en)

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DE10243017A DE10243017B4 (en) 2002-01-30 2002-09-17 Ceramic composite and glow plug with such a composite material
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DE102004045814A1 (en) * 2004-09-22 2006-03-23 Robert Bosch Gmbh Process for the preparation of a precursor ceramic
US20090184101A1 (en) * 2007-12-17 2009-07-23 John Hoffman Sheathed glow plug
CN109824364A (en) * 2019-03-26 2019-05-31 华南理工大学 A kind of synthetic method of SiAlZrOC ceramics
CN112441824B (en) * 2020-12-11 2021-06-29 湖南兴诚电瓷电器有限公司 Low-temperature-resistant high-voltage power transmission porcelain insulator and preparation method thereof

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US4033776A (en) * 1975-08-18 1977-07-05 Saxonburg Ceramics, Inc. Composition of ceramic material
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US5527872A (en) * 1990-09-14 1996-06-18 At&T Global Information Solutions Company Electronic device with a spin-on glass dielectric layer
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DE10020328A1 (en) * 1999-08-27 2001-03-01 Bosch Gmbh Robert Ceramic glow plug

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