EP0636113A1 - Procede servant a ameliorer la resistance de materiaux en ceramique au moyen d'un revetement de surface en ceramique et produit correspondant - Google Patents

Procede servant a ameliorer la resistance de materiaux en ceramique au moyen d'un revetement de surface en ceramique et produit correspondant

Info

Publication number
EP0636113A1
EP0636113A1 EP93909284A EP93909284A EP0636113A1 EP 0636113 A1 EP0636113 A1 EP 0636113A1 EP 93909284 A EP93909284 A EP 93909284A EP 93909284 A EP93909284 A EP 93909284A EP 0636113 A1 EP0636113 A1 EP 0636113A1
Authority
EP
European Patent Office
Prior art keywords
ceramic material
coating
structural ceramic
preceramic
ceramic
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Withdrawn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
EP93909284A
Other languages
German (de)
English (en)
Inventor
Yigal D. Blum
Gregory A. Mcdermott
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.)
SRI International Inc
Original Assignee
SRI International Inc
Stanford Research Institute
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by SRI International Inc, Stanford Research Institute filed Critical SRI International Inc
Publication of EP0636113A1 publication Critical patent/EP0636113A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • 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
    • C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
    • 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
    • C04B41/4505—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements characterised by the method of application
    • C04B41/455—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements characterised by the method of application the coating or impregnating process including a chemical conversion or reaction
    • 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
    • C04B41/52—Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
    • 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
    • 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
    • C04B41/89—Coating or impregnation for obtaining at least two superposed coatings having different compositions
    • 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
    • C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/72—Repairing or restoring existing buildings or building materials

Definitions

  • the invention relates to the strengthening of structural ceramic materials by forming a polymer-derived ceramic coating on the surface of the structural ceramic material.
  • the invention additionally relates to a process for improving the strength of and repairing surface defects in structural ceramic materials by coating them with a polymer-derived preceramic layer and then converting the preceramic layer to a ceramic coating.
  • the invention relates to a process for strengthening structural silicon nitride and alumina materials by coating them with a polymer-derived preceramic layer and then converting the preceramic layer to a ceramic coating.
  • the invention can replace elaborate and costly fine machining of ceramic materials.
  • Wieczorrek et al. U.S. Patent No. 4,409,266, provides a shatterproof coating on glass by applying to the glass surface a silane adhesion promoter and a two-component system which reacts to form a polyurethane binder.
  • U.S. Patent No. 4,656,221 conceals graze marks on a glass bottle by coating the glass with a composition formed from polydiorganosiloxane components and a surfactant. The coating is applied to the glass surface as an emulsion and allowed to air dry.
  • the formation of ceramic coatings on substrates through the pyrolysis of preceramic polymer coatings is known.
  • Gaul in U.S. Patent Nos. 4,395,460 and 4,404,153, forms a silicon carbide coating on a substrate by coating the substrate with a polysilazane polymer and then heating the coated substrate in an inert atmosphere or in a vacuum to an elevated temperature of at least 750°C.
  • Seyferth et al. U.S. Patent Nos.4,482,669; 4,720,532; 4,705,837; and 4,645,807, teach forming an oxidation-resistant coating on otherwise oxidizable materials such as pyrolytic graphite by application of a preceramic polymer coating over the materials followed by pyrolysis of the preceramic coating to form a ceramic coating.
  • the preceramic polymer materials respectively used in the Seyferth et al.
  • patents include: (1) polysilazanes that are synthesized by strong base-catalyzed polymerization of cyclomethylsilazane, which is the ammonolysis product formed by reacting anhydrous ammonia with a mixture of dihalohydridosilanes and trihalosilanes; (2) polymers formed by reacting polysiloxane with a polysilylamide, which is an intermediate potassium salt of the polymer in (1); and (3) polymers formed by reacting an organopolysilane of the formula [(RSiH) ⁇ (RSi) y] ⁇ with alkali metal amides or silylamides. See also Cramer, Ceramic Bulletin. Vol.68, No.2, 1989, pp.415- 419.
  • U.S. Patent No. 4,668,642 discloses coating substrates with R3S1NH- containing silazane polymers to which have been added certain boron compounds, followed by heating the substrate to an elevated temperature of at least 750°C in an inert atmosphere or vacuum to form a ceramic-coated article.
  • Such ceramic materials may generally protect the surface of a substrate against scratching or other abrasive action, as well as imparting some oxidation protection for oxidizable substrates such as the above-described carbonaceous materials, such coatings are not generally known to impart any physical strength to the substrate itself when applied as thin layers, e.g., less than 10 microns in thickness.
  • Structural ceramic materials in addition to needing surface protection such as afforded by the above discussed organic coating materials, need physical strengthening as well.
  • Barbee et al. U.S. Patent No.4,781,970 describes strengthening of ceramics and glass- ceramics such as spumodumene (L ⁇ 2 ⁇ -Al2 ⁇ 3-4Si ⁇ 2) an( ⁇ cordierite (2MgO-2Al2 ⁇ 3 * 5Si ⁇ 2) by chemical vapor deposition or sputtering deposition of Si ⁇ 2- The strengthening of the ceramic substrates by the invention of Barbee et al.
  • 4,952,715 delineate a novel class of silazanes including cyclomeric silazane units within an oligomeric or polymeric structure.
  • Blum et al., U.S. Patent No. 5,055,431 describe the synthesis of silazane and polysilazane compounds which have more than one cyclomeric silazane in their structure, the pyrolysis of these compounds upon fabrication to give ceramic coatings, fibers and articles as well as the use of the compounds as binders.
  • the disclosures of these related patents are hereby incorporated by reference in their entirety.
  • the idea behind this invention is that deposition of ceramic precursor solutions at surface and subsurface defects, followed by pyrolysis, can restore or even improve the original strength of the material and repair damage caused by machining.
  • the invention can replace elaborate and costly fine machining of ceramic materials.
  • a method for improving the strength of a structural ceramic material which comprises: coating the structural ceramic material with a tractable ceramic precursor coating capable of pyrolyzing to form a ceramic coating; and heating the coated structural ceramic material to a temperature sufficiently high to permit conversion of the ceramic precursor for a period of time sufficient to form the ceramic coating on the surface of the structural ceramic material.
  • tracetable as used herein with respect to the preceramic coating material used in the practice of the invention, is intended to define a material which is soluble in organic or inorganic solvents, meltable, or malleable, or which can be processed like an organic polymer to form a desired shape, i.e., in this case, a coating on a ceramic substrate.
  • pyrolysis or “pyrolyze” is meant the transformation of the preceramic coating material or precursor, to a ceramic product by a heating process in which a multiple thermal reactivity occurs, or the reaction of such materials with oxygen or nitrogenous gas or other gases present during the pyrolysis to form materials separable from the resulting ceramic coating on the structural ceramic material. It also may be defined as the minimum temperature at which formation of a ceramic coating occurs for any given preceramic coating material, e.g., polymer or precursor, by losing its functional groups or nature coincidentally with the extensive formation of crosslinking.
  • the "ceramic” which is formed by the pyrolysis may be defined as an inorganic material that forms a highly crosslinked network of covalent (sigma) bonds which may contain additional coordination bonds. In most cases, except carbon, the ceramic material contains at least two chemical elements. In some cases both are metals or metalloids, e.g., borides and suicides, or non-metals, e.g., PN, ASS3, or S.1PO4.
  • the ceramic material can be in an amorphous, crystalline, glass-ceramic, or solid solution form and usually is stable at high temperature.
  • structural ceramic material or “ceramic substrate” are used interchangeably herein to define the material or substrate onto the surface of which the polymer-derived ceramic coating is formed by pyrolyzing a preceramic coating material applied to said surface as herein disclosed.
  • ceramic to describe the substrate is as defined above.
  • the structural ceramic materials may include Si3N SiC,
  • ceramic yield of the ceramic precursor coating material, such as a precursor or preceramic polymer, upon pyrolysis, as used herein, is intended to define the ratio of the weight of the ceramic coating after pyrolysis to the weight of the coating before pyrolysis.
  • ceramic precursor as used herein is intended to include inorganic and organometallic compounds, inorganic polymers, and organometallic polymers, while the term “preceramic polymer” is intended to define a tractable compound with any number of monomeric units which is sufficient to be deposited as a coating on substrates and to form ceramic compositions upon pyrolysis or heat treatment. Both terms are intended to be included in the term “ceramic precursor coating material”.
  • the invention provides a process for improving the strength of a structural ceramic material by forming a ceramic coating on the surface of the structural ceramic material. The ceramic coating is formed by applying a preceramic coating material to the surface of the structural ceramic material and then pyrolyzing or heating the preceramic coating material at a temperature sufficiently high to permit the conversion of the precursor coating to a ceramic coating.
  • the strength of the structural ceramic material may be increased, on the average, by 15%. A few examples have shown increases of up to 20% to 30%. While not wishing to be bound by any particular theory as to why such strength increases occur, we have theorized that the ceramic coating material may act to increase the strength of the substrate material by healing surface defects in the substrate material. The present inventors further postulate that chemical or physical interactions between the coating and the substrate play a role in the strengthinging mechanism. Stress-corrosion effect may be another mechanism to improve the strength. Chemical interactions between the substrate and the coating may be advantageous but migration of material from the substrate surface area to the coating should be prevented if it will cause the formation of undercoating holes and pinholes and/or cracks in the coatings.
  • the preceramic coating material e.g., a polymer or precursor, from which the ceramic coating will be formed may comprise any tractable inorganic or organometallic polymer or compound capable of being in a liquid form or in solution and of wetting and adhering to the surface of the structural ceramic material and capable of converting to a ceramic coating on a ceramic substrate by heat treatment.
  • the ceramic coatings which may be formed from such precursors may contain Si3N SiCN, SiC, C,
  • preceramic coating materials such as polymers or precursors from which such ceramic coatings may be formed comprise polysilazanes, such as poly-N-methylsilazane and/or polycyclomethylsilazane, from which ceramic compositions of SiN, SiCN, Si ⁇ 2,
  • SiOC, SiON and SiOCN may be formed; polysiloxazane; polysiloxane, including polymethyl-silsesquioxane and polyhydridomethylsiloxane from which ceramic coating containing Si and O and potentially other elements such as C and N can be formed; polysilanes; polycarbosilanes; polyboranes; polycarboranes; polyaminoboranes; polyaminotitanium; and combinations thereof. Examples may also include precursors to Ti ⁇ 2, A1N, AI2O3, Zr ⁇ 2, meta l phosphates, and others.
  • preceramic coating materials either may be obtained commercially or may be readily synthesized using methods know to those skilled in the art. Reference may also be had to U.S. Patent Nos. 4,612,383, 4,788,309, 4,952,715, 5,008,422 and
  • ceramic precursor coating materials may include compounds and polymers which are totally inorganic and soluble in water.
  • inorganic ceramic precursor coating materials may include Ca ⁇ PO ⁇ and AIO ⁇ PO ⁇ .
  • Precursors made by sol-gel technology may also be used. However, they are expected to be less favorable due to short term stability in solution or on the shelf, and low ceramic yields and high shrinkage are obtained upon their pyrolysis.
  • the ceramic yield of the precursor be at least 50 wt.%. More preferably, it should be above 70 wt.% and most preferably, it should be above 85 wt.%.
  • the structural ceramic material which may be strengthened by formation of the ceramic coating thereon, in accordance with the invention may comprise any particular shape, including flat sheets, and shaped objects, such as bars, rods, fibers or the like.
  • the structural ceramic material which may be strengthened by formation of the ceramic coating thereon, in accordance with the invention may include, by way of example and not of limitation, silicon nitride and AI2O3.
  • pretreat the structural ceramic material may sometimes be preferred or necessary to pretreat the structural ceramic material with HF or other acids or tetrachlorosilane in order to hydroxylate the surface and thereby to optimize the coating of the ceramic substrate with the preceramic coating material. Whether or not it is necessary to pretreat the structural ceramic material and the methods whereby such pretreatment is to be effected may be determined using routine experimental techniques. The choice of the preceramic coating material and the pyrolysis schedule may vary depending on the substrate material. It is not necessary that a type of polymer that performed well for one kind of material will strengthen another type of material. The chemical interactions at the interface between the coating and the substrate is assumed to play a role in the strengthening mechanism.
  • the preceramic coating material may be applied to the ceramic substrate by any convenient method such as by dipping in a selected coating solution or by spraying, painting, spinning, or the like, with such coating solution, the solution having a predetermined concentration preferably between 0.1 and 100 wt.%, more preferably between about 5 and 30 wt.% for most applications.
  • the preceramic coating material is applied to the ceramic substrate in an amount sufficient to provide, upon subsequent pyrolysis, a ceramic coating of from about 0.01 to about 20 microns and preferably from about 0.05 to about 4 microns.
  • the desired ceramic coating thickness is achieved in a single coating layer, i.e., without the use of several built-up layers. However, if necessary, the coating process may be repeated to build up the desired thickness without the formation of a substantial level of cracks in the developed ceramic coating. Li addition, cracked coatings can be healed by additional coating procedure.
  • Achieving the desired thickness of the eventual ceramic coating layer on the structural ceramic material is related to both the initial coating thickness of the preceramic coating material and the ceramic yield of the preceramic coating material, e.g., polymer or precursor.
  • the coating thickness of the preceramic coating material is, in turn, related to the viscosity of the coating material solution and the amount of solvent added to it to permit it to be applied to the surface of the ceramic substrate.
  • the ceramic yield is related to: (1) the molecular structure with reference to whether the coating material comprises a branched, crosslinked, or ring-type polymer; (2) the molecular weight of the coating material with higher molecular weight polymers favored because of the higher ceramic yield of such materials; (3) the latent reactivity of the coating material that allows thermosetting properties and further crosslinking as desired in (2); and (4) small amounts of extraneous organic groups if needed to provide tractability and shelf stability.
  • the preceramic coating material should have a sufficient molecular weight, e.g., be sufficiently polymerized, to provide a minimum viscosity, after removal of solvent, of at least 1-3 poise so that the coating will remain in a uniform thickness on the structural ceramic material as the coating is heated to the pyrolysis temperature.
  • the precursor can be a monomeric compound capable of condensation or cross- linking at the substrate surface prior to evaporation.
  • the preceramic coating material although sufficiently polymerized to achieve the desired ceramic yield, will have a viscosity sufficiently low to permit it to be applied to the structural ceramic material as a uniform and homogeneous coating without the necessity of diluting the coating material in a solvent, i.e., the "tractable" coating material, such as a polymer, will be liquid or, by application of heat, meltable.
  • the preceramic coating material will need to be diluted to lower the viscosity sufficiently to facilitate application of the preceramic coating material as a coating on the surface of the ceramic substrate and to control the thickness of the coating.
  • the preceramic coating material must be capable of being dissolved in a solvent which may later be removed from the coating without negative impact on the desired formation of the ceramic coating layer, i.e., the "tractable" coating material must be soluble.
  • the preceramic coating material such as a polymer or precursor, must not only be of sufficiently high molecular weight or non-volatile, or cross-linkable, to achieve the desired minimum ceramic yield, but it must be "tractable” as well, as previously defined.
  • the preceramic coating material may be applied to the structural ceramic material at ambient temperature, i.e., about 20-25°C, or either the coating material or the structural ceramic material may be at an elevated temperature.
  • the preceramic polymer is sensitive to moisture and/or oxygen
  • a polymer that is not air sensitive or only slightly air sensitive as this will not require special costly equipment and more expensive operation.
  • polymers sensitive to air may be preferably coated in air or exposed to air immediately after the coating procedure and prior to heat treatment to allow curing at low temperature.
  • the minimum temperature to which the coated structural ceramic material must be heated will be determined by the particular preceramic coating material used and the minimum temperature at which a ceramic material may be formed from such a preceramic coating material.
  • the minimum pyrolysis temperature must be at least at, and preferably above, the temperature at which the preceramic coating material converts to a ceramic material. This determination of the conversion of the preceramic coating material to a ceramic material may be TGA, IR, XRD, NMR, and elemental analysis.
  • the minimum temperature must be high enough to permit organic groups, if contained in the preceramic coating material, e.g., polymer or organometallic compound, to be pyrolyzed, leaving only an inorganic ceramic network.
  • the minimum temperature needed to remove extraneous methyl groups from the coating and to form the ceramic material is about 300°C to 550°C.
  • higher temperatures may be needed to allow desired chemical or physical interactions between the coating and the substrate or to densify or crystalize the ceramic coating materials.
  • the preceramic coating material may be pyrolyzed to convert it into a ceramic coating using a variety of heating schedules, including different heating rates, dwell times at intermediate and maximum temperatures, and cooling rates, depending upon the specific material used.
  • the coated ceramic substrate is held at the pyrolysis temperature for a period of time sufficient to permit formation of the ceramic coating and to develop the desired strength. It will be understood that if less than the optimal dwell time is used for the particular preceramic coating and structural ceramic material, a ceramic coating may be formed over the ceramic substrate in accordance with the invention, but the coated ceramic substrate may not have as much strength or hardness as is possible if the dwell time is extended. There will then be a trade-off between desired strength and process economics.
  • the holding or dwell time of the coated ceramic substrate at the pyrolysis temperature may, therefore, vary from a minimum of 0 minutes, preferably at least about 5 minutes, and most preferably at least about 90 minutes, up to a maximum time of about 2 hours. Longer time periods may be used, but are usually unnecessary and, therefore, not economically justifiable. In some instances shorter dwell times of, for example, 30-60 minutes may be used, even though maximum strength has not been developed, if the economics of the process justifies the trade-off of reduced dwell time with reduced strength.
  • the entire pyrolysis period is carried out in a period of about 2 hours.
  • the entire pyrolysis period is meant from the time the coated ceramic substrate is placed in the furnace at room temperature until the temperature during cooling again reaches 200"C.
  • the coated-structural ceramic material during both the temperature ramp-up period and the dwell period, may be maintained in an inert atmosphere such as argon, a nitrogen- containing atmosphere such as N2 or ammonia, a hydrogen atmosphere, or mixtures of the aforementioned atmospheres, and a dry- or wet-air atmosphere, depending upon the chemical constituents of the preceramic polymer and the desired ceramic-coating composition.
  • an inert atmosphere such as argon
  • a nitrogen- containing atmosphere such as N2 or ammonia
  • hydrogen atmosphere or mixtures of the aforementioned atmospheres
  • a dry- or wet-air atmosphere depending upon the chemical constituents of the preceramic polymer and the desired ceramic-coating composition.
  • the choice of the pyrolysis environment in conjunction with the preceramic polymer structure will determine the final ceramic composition. Any precursor that is pyrolyzed in air will provide a final composition consisting mainly of oxide material. If the pyrolysis is conducted in an inert atmosphere such as nitrogen or argon, the final composition will contain substantial amounts of carbon if the precursor contained organic pendant groups or carbon was an element in the polymer skeleton (e.g., polycarbosilane). If nitride coating is desired then the polymers should be preferably pyrolyzed in ammonia. Oxynitride and oxycarbide coatings can also be formed if oxygen is incorporated in the skeleton of the original polymer or during the pyrolysis period.
  • the choice of the final coating material might vary based on the application and the physical and/or chemical conditions at which the product is going to perform. However, for economic reasons, it is preferable to conduct the pyrolysis in air.
  • the following examples will serve to further illustrate the invention, including some of the parameters of the process.
  • Example 1 Five ground, highly polished beveled silicon nitride bars, the dimensions of which were approximately 50 mm x 4 mm x 3 mm, were ultrasonically cleaned and then dehydrated by heating at 500"C under nitrogen for 1 hour. Bars were then dipped into a 10 wt.% polymer solution in tetrahydrofuran (unless otherwise indicated) under a selected atmosphere and pyrolyzed as described below.
  • k Heat treated 3 times to 900°C at a rate of 10 ⁇ C per min with a dwell period of 2 hours each time.
  • c Polycarbosilane in tetrahydrofuran solution. The polycarbosilane was treated with 50 ppm Ru3(CO)2 as a crosslinking catalyst found to effectively increase the ceramic yields.
  • Example 2 The procedures of Example 1 can be followed using as-ground silicon nitride bars and thereby achieve essentially identical results (see Table 2).
  • Example 1 The procedures of Example 1 can be followed using Al 2 O3 bars and thereby achieve essentially identical results (see Table 3).

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Ceramic Products (AREA)
  • Silicon Polymers (AREA)
  • Application Of Or Painting With Fluid Materials (AREA)

Abstract

L'invention décrit un procédé servant à améliorer la résistance d'un matériau en céramique, ainsi qu'à en réparer les défauts superficiels, comprenant le revêtement dudit matériau par un matériau de revêtement en pré-céramique ductile présentant une caractéristique de pyrolyse, de façon à constituer un revêtement en céramique, ainsi que le réchauffement du matériau en céramique revêtu jusqu'à une température suffisamment élevée pour permettre la pyrolyse du polymère en pré-céramique pendant une durée suffisante pour former un revêtement en céramique sur la surface dudit matériau.
EP93909284A 1992-04-14 1993-04-08 Procede servant a ameliorer la resistance de materiaux en ceramique au moyen d'un revetement de surface en ceramique et produit correspondant Withdrawn EP0636113A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US86860892A 1992-04-14 1992-04-14
US868608 1992-04-14
PCT/US1993/003290 WO1993021131A1 (fr) 1992-04-14 1993-04-08 Procede servant a ameliorer la resistance de materiaux en ceramique au moyen d'un revetement de surface en ceramique et produit correspondant

Publications (1)

Publication Number Publication Date
EP0636113A1 true EP0636113A1 (fr) 1995-02-01

Family

ID=25352001

Family Applications (1)

Application Number Title Priority Date Filing Date
EP93909284A Withdrawn EP0636113A1 (fr) 1992-04-14 1993-04-08 Procede servant a ameliorer la resistance de materiaux en ceramique au moyen d'un revetement de surface en ceramique et produit correspondant

Country Status (4)

Country Link
EP (1) EP0636113A1 (fr)
JP (1) JPH07505855A (fr)
CA (1) CA2131016A1 (fr)
WO (1) WO1993021131A1 (fr)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE19500832C2 (de) * 1995-01-13 1998-09-17 Fraunhofer Ges Forschung Dichter Siliziumnitrid-Kompositwerkstoff und Verfahren zu seiner Herstellung
US6413578B1 (en) * 2000-10-12 2002-07-02 General Electric Company Method for repairing a thermal barrier coating and repaired coating formed thereby
JP5500671B2 (ja) * 2009-09-01 2014-05-21 一般財団法人ファインセラミックスセンター 成形材料及びその製造方法並びにこれを備える高温過熱蒸気生成システム

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5128494A (en) * 1985-04-26 1992-07-07 Sri International Hydridosiloxanes as precursors to ceramic products
US4617232A (en) * 1982-04-15 1986-10-14 Kennecott Corporation Corrosion and wear resistant graphite material
JP3059453B2 (ja) * 1988-08-01 2000-07-04 エス・アール・アイ・インターナシヨナル 表面にセラミツク被膜を形成させることによりガラスの強度を増大させる方法並びにそれによって作られた製品
DE3904118A1 (de) * 1989-02-11 1990-08-16 Hoechst Ag Hochfeste verbundkeramik, verfahren zu ihrer herstellung sowie ihre verwendung

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9321131A1 *

Also Published As

Publication number Publication date
JPH07505855A (ja) 1995-06-29
CA2131016A1 (fr) 1993-10-28
WO1993021131A1 (fr) 1993-10-28

Similar Documents

Publication Publication Date Title
US5162136A (en) Process for increasing strength of glass by forming ceramic coating on glass surface
US5358739A (en) Coating electronic substrates with silica derived from silazane polymers
US5635240A (en) Electronic coating materials using mixed polymers
Bauer et al. Preparation of moisture curable polysilazane coatings: Part I. Elucidation of low temperature curing kinetics by FT-IR spectroscopy
KR880008439A (ko) 실리케이트 에스테르로부터의 다중층 세라믹
US5789325A (en) Coating electronic substrates with silica derived from polycarbosilane
EP0266860A2 (fr) Polymères précurseurs de céramiques infusibles par traitement de plasma
Motz et al. Special modified silazanes for coatings, fibers and CMC's
EP0636113A1 (fr) Procede servant a ameliorer la resistance de materiaux en ceramique au moyen d'un revetement de surface en ceramique et produit correspondant
EP0883165A2 (fr) Méthode de fabrication d'une couche sans cracks à base de résine silséquioxane hydrogenée
CA1284749C (fr) Enduits a teneur de si-n pour dispositifs electroniques
Blum et al. Glass Strengthening by Polymer‐Derived Ceramic Coatings
US5912047A (en) Borosilicate electronic coatings
EP0397808B1 (fr) Procede d'augmentation de la resistance du verre par formation d'un revetement ceramique sur la surface, et produit ainsi forme
SK157795A3 (en) Abrasion-proof protective layer against oxidation of silicon(iv) carbide bodies
JP3422515B2 (ja) 炭素質基材の耐酸化性被膜形成法
KR101204013B1 (ko) 저온 실리콘카바이드 코팅층 형성 방법
JP2812019B2 (ja) 炭素繊維／炭素複合材
RU2276661C2 (ru) Способ обработки изделий из керамических материалов на основе карбида кремния и/или углерода
JPH11292645A (ja) 耐酸化性ｃ／ｃ複合材及びその製造方法
EP0749155A2 (fr) Revêtements composites pour l'électronique
KR100287964B1 (ko) 금속 기지상의 실리카 코팅막 제조방법
Loh et al. Coating with amorphous silicon carbide using polymeric precursors
JPH0859377A (ja) 炭素繊維強化炭素複合材の耐酸化処理法
Johnson et al. Interfaces of polymeric precursors with ceramics/metals

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19941107

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17Q First examination report despatched

Effective date: 19950411

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 19950822