(19)
(11)EP 2 578 556 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
28.06.2017 Bulletin 2017/26

(21)Application number: 12186980.4

(22)Date of filing:  02.10.2012
(51)Int. Cl.: 
C04B 41/89  (2006.01)
C03C 14/00  (2006.01)
C04B 41/00  (2006.01)
C04B 35/628  (2006.01)
C04B 35/80  (2006.01)
F01D 5/28  (2006.01)
C04B 41/52  (2006.01)
C23C 16/04  (2006.01)

(54)

Method and ceramic component

Verfahren und keramische Komponente

Procédé et composant céramique


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

(30)Priority: 03.10.2011 US 201113251696

(43)Date of publication of application:
10.04.2013 Bulletin 2013/15

(73)Proprietor: United Technologies Corporation
Farmington, CT 06032 (US)

(72)Inventors:
  • Schmidt, Wayde R.
    Pomfret Center, CT Connecticut 06259 (US)
  • Jarmon, David C.
    Kensington, CT Connecticut 06037 (US)

(74)Representative: Hull, James Edward 
Dehns St. Bride's House 10 Salisbury Square
London EC4Y 8JD
London EC4Y 8JD (GB)


(56)References cited: : 
EP-A1- 0 481 629
WO-A1-2011/114810
US-A- 4 615 935
EP-A2- 0 866 041
FR-A1- 2 882 356
  
  • John Brennan ET AL: "Processing and properties of coated hpz fiber reinforced glass-ceramic matrix composites", , March 1993 (1993-03), XP055071214, Retrieved from the Internet: URL:http://www.dtic.mil/cgi-bin/GetTRDoc?L ocation=U2&doc=GetTRDoc.pdf&AD=ADA265177 [retrieved on 2013-07-12]
  
Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


Description

BACKGROUND



[0001] This disclosure relates to ceramic materials. Ceramic materials are known and used for components such as coatings, ceramic bodies and ceramic matrices. For example, ceramic materials are fabricated using techniques such as polymer impregnation and pyrolysis, melt infiltration, slurry infiltration, slip casting, tape casting, injection molding, dry pressing, isostatic pressing, hot isostatic pressing and others. The selected processing technique controls the chemistry and microstructure of the ceramic material and thus can also limit the chemistry and microstructure.

[0002] A prior art method of forming a ceramic matrix composite is disclosed in "Processing and properties of coated HPZ fiber reinforced glass-ceramic matrix composites", John Brennan et al., March 1993. Other prior art processes are disclosed in FR-2882356 and EP-0866041.

SUMMARY



[0003] According to the present invention, there is provided a method of fabricating a ceramic component as claimed in claim 1 and a ceramic component as claimed in claim 8.

[0004] The method may include using vapor infiltration to deposit a coating having a first coefficient of thermal conductivity within pores within a porous fibrous structure to form a preform body with residual interconnected porosity. The porous fibrous structure includes fibers that are coated with a protective coating. A heated, liquid glass or glass/ceramic material is then deposited within the residual porosity of the preformed body using transfer molding. The liquid glass or glass/ceramic material is then cooled to form a solid glass or glass/ceramic material that has a second coefficient of thermal conductivity that is lower than the first coefficient of thermal conductivity of the coating.

BRIEF DESCRIPTION OF THE DRAWINGS



[0005] The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows.

Figure 1 illustrates an example method of fabricating a ceramic component.

Figure 2 illustrates various stages through fabrication of a ceramic component.


DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT



[0006] Figure 1 illustrates an example method 20 of fabricating a ceramic component. As will be appreciated, the method 20 permits fabrication of ceramic components having unique compositions and/or microstructures that are not heretofore available. Furthermore, the method 20 can be used to produce compositions and/or microstructures for the enhancement of densification, thermal conductivity or other target property in components such as cooled turbine engine components.

[0007] As illustrated in Figure 1, the method 20 generally includes a vapor infiltration step 22, a transfer molding step 24 and a solidification step 26.

[0008] As shown, in step 22 a ceramic coating is deposited using vapor infiltration within pores of a porous structure to form a preform body with residual interconnected porosity. As an example, the vapor infiltration includes chemical vapor infiltration (CVI) in which one or more volatile ceramic precursors penetrate into the porous structure and react to deposit the ceramic material within the porous structure. The deposited ceramic material is a result of chemical reaction of the ceramic precursor(s) occurring at the internal surfaces of the porous structure. The infiltration of the precursor(s) is driven by diffusion, an imposed external gas pressure, an imposed vacuum or a combination of these. In one non-limiting example based on silicon carbide, the precursor is methyltrichlorosilane mixed in a hydrogen carrier gas. The methyltrichlorosilane decomposes to silicon carbide. In general, the temperature, time, precursor(s), carrier gas(es), pressure and flow rate(s) are selected to control the composition and amount of the resulting ceramic coating that is deposited.

[0009] The vapor infiltration step 22 is controlled such that the resulting residual porosity of the preform body is within a predefined range. The predefined range is 40 - 80 volume percent of the preform body. If the ceramic coating reduces the residual porosity to less than about 40 volume percent, the interconnectivity of residual porosity is reduced such that the liquid glass material is unable to later substantially fully infiltrate the porosity to form a near fully dense component.

[0010] In the transfer molding step 24, a heated, liquid glass or glass/ceramic material is deposited within the residual porosity of the preform body using transfer molding. The liquid glass or glass/ceramic material is then cooled at step 26 to increase viscosity and thereby immobilize the glass or glass/ceramic material as a solid to form a ceramic material that includes the solid glass or glass/ceramic material, the ceramic coating and the porous structure. As an example, the preform body is subjected to a ceramic glass-transfer molding process in which the body is located in a suitable molding tool. Molten glass or glass/ceramic of the selected composition is injected into the tool cavity to infiltrate the residual porosity of the preform body. The body is cooled to solidify the glass or glass/ceramic into a solid glass or glass/ceramic material. Optionally, a thermal heat treatment is conducted after solidification to induce selective crystallization of ceramic phase(s) within the glass or glass/ceramic. An example temperature range for the heat treatment is from about 1000°C to about 1500°C for times ranging from about 10 minutes to about 4 hours.

[0011] As used herein, the term "ceramic" refers to inorganic, non-metallic materials that may be crystalline, partially crystalline or substantially or fully amorphous, and including allotropes of carbon, such as graphite and diamond. Further, the term "glass" as used herein, refers to an amorphous or partially amorphous ceramic material. In one embodiment, the ceramic coating is different from the glass or glass/ceramic material in at least one of composition, microstructure and physical property. In a further embodiment, the ceramic coating is a crystalline ceramic material and the glass or glass/ceramic material is partially or fully amorphous.

[0012] The chemical composition of the ceramic coating, porous structure and glass or glass/ceramic material can be tailored to control the desired properties of the final ceramic component that is formed by method 20. In one example, the method 20 is used to enhance thermal conductivity of the composite material. For instance, the ceramic coating that is deposited into the pores of the porous structure has a first thermal conductivity and the glass or glass/ceramic material has a second thermal conductivity that is lower than the first coefficient of thermal conductivity. Thus, the ceramic coating acts as a thermal transfer network in the ceramic component while the glass or glass/ceramic material enhances other properties, such as thermal resistance, dimensional stability and corrosion resistance.

[0013] In a further embodiment, the ceramic coating is a non-oxide ceramic material. In a further example, the ceramic coating is selected from silicon carbide, aluminum nitride, boron nitride, boron phosphide, silicon nitride, beryllium oxide, diamond or other solid with high thermal conductivity or combinations thereof.

[0014] In a further embodiment, the porous structure is a porous fibrous structure. For example, the porous fibrous structure is a fabric, weave, tape, braid, two-dimensional, or three-dimensional structure that is coated or uncoated with a protective coating. In one example, the porous fibrous structure includes ceramic fibers and/or carbon fibers. The ceramic fibers include oxide or non-oxide ceramic fibers. In a further example, the ceramic fibers are silicon carbide fibers. In other examples, the fibers are silicon oxycarbide, silicon oxycarbide with refractory metal dopants such as Ti, B, Zr, or Hf and/or glass or glass/ceramic fibers. It is to be understood that the porous structure may alternatively be another kind of porous structure that may or may not include fibers.

[0015] In a further embodiment, the porous fibrous structure includes a protective coating on the fibers. The protective coating includes an oxide layer, a non-oxide layer or both and can be a monolayer coating or a multilayer coating. For instance, the protective coating includes one or more layers of carbon, boron nitride, boron carbide, silicon nitride, silicon carbide and aluminosilicate including combinations of these, including alternating layers of different compositions.

[0016] In a further embodiment, the ceramic glass is a silicate-based glass or glass/ceramic. For example, the silicate-based glass or glass/ceramic includes boron, barium, magnesium, lithium, aluminum or combinations thereof. In a further example, the silicate-based glass or glass/ceramic additionally includes a nucleating agent that serves to precipitate crystalline phases from the amorphous phase with the application of thermal treatment. In one non-limiting example, the nucleating agent includes zirconium.

[0017] In a further embodiment, the selected glass or glass/ceramic material additionally includes a solid filler to modify the properties of the ceramic component. In one example, the solid filler is a solid ceramic filler, such as silicon carbide. In other examples, the solid filler is a silicon-containing filler, such as oxides, nitrides, borides, carbides and combinations thereof that include silicon.

[0018] In a further embodiment, the chemical compositions of the ceramic coating, porous structure and glass or glass/ceramic material are selected to enhance the transfer molding step 24. For example, the compositions of the ceramic coating and the glass or glass/ceramic material disclosed herein are compatible such that the glass or glass/ceramic material in the liquid state wets the ceramic coating to aid in substantially fully filling the residual interconnected porosity during the transfer molding step 24. The compatibility between the ceramic coating and the glass or glass/ceramic material reduces the molding pressure needed in the transfer molding step 24 and thus enhances filling of the pores and process efficiency and repeatability. Furthermore, the composition, temperature and/or pressure can be adjusted to change the viscosity of the glass or glass/ceramic material to enhance the filling of the pores. The residual porosity in the preform body is 40 - 80 volume percent and the liquid ceramic glass material is molded at a viscosity of about 5 - 15 Pa·s and a molding pressure of about 0.5 - 1.5 ksi (3.4 - 10.3 megapascals) to produce a residual void volume of less than one volume percent in the final ceramic component. In a further example of the compatibility, the chemical composition of the ceramic coating includes, as a constituent element, at least one element in common with the chemical composition of the glass or glass/ceramic material.

[0019] Figure 2 illustrates three different stages (A), (B) and (C) in a fabrication of a final ceramic component 40 according to the method 20. It is to be understood that the method 20 is not limited to fabrication of the exemplary ceramic component 40. As shown in initial stage (A), a porous fibrous structure 42 includes a plurality of fibers 44 that define open pores 46 there between. In this example, each of the fibers 44 includes a protective coating 44a of composition described herein disposed on the outer surfaces of the fibers 44.

[0020] The fibers 44 in this example are transversely oriented to each other such that there is a first layer of parallel fibers and an adjacent second layer of parallel fibers that are orientated at approximately 90 degrees to the fibers of the first layer. Given this description, one of ordinary skill in the art will recognize other fiber orientations and arrangements to meet their particular needs.

[0021] Referring to stage (B), a ceramic coating 48 is deposited into the pores 46 of the porous fibrous structure 42 to form a preform body 50 with residual interconnected porosity 52.

[0022] At stage (C), the liquid glass or glass/ceramic material is transfer-molded into the residual interconnected porosity 52 of the preform body 50. Upon solidification, solid glass or glass/ceramic material 54 substantially fills the residual interconnected porosity 52. The ceramic component 40 is thus formed of the solid glass or glass/ceramic material 54, the ceramic coating 48 and the porous fibrous structure 42.

[0023] The ceramic component 40 fabricated according to method 20 includes a final composition, by volume percentage, of:

20-70 of the fibers 44,

up to 5 of the protective coating 44a on the fibers 44,

5-20 of the ceramic coating 48, and

a remainder of the solid glass or glass/ceramic material 54 and residual void volume, wherein the residual void volume is less than 1 volume percent. It is to be understood that the volume percentages of the constituents in the final composition must total 100%.



[0024] In a further example, the final composition from above includes:

30-60 of the fibers 44,

1-2 of the protective coating 44a on the fibers 44, and

20-40 of the solid glass or glass/ceramic material 54.



[0025] Although a combination of features is shown in the illustrated examples, not all of them need to be combined to realize the benefits of various embodiments of this disclosure. In other words, a system designed according to an embodiment of this disclosure will not necessarily include all of the features shown in any one of the Figures or all of the portions schematically shown in the Figures. Moreover, selected features of one example embodiment may be combined with selected features of other example embodiments.

[0026] The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. The scope of legal protection given to this disclosure can only be determined by studying the following claims.


Claims

1. A method of fabricating a ceramic component (40), the method comprising:

using vapor infiltration to deposit a ceramic coating (48) within pores (46) of a porous structure (42) to form a preform body (50) with residual interconnected porosity (52), wherein the residual porosity is 40-80 volume percent;

using transfer molding to deposit a heated, liquid glass or glass/ceramic material (54) within the residual interconnected porosity (52) of the preform body (50); and

solidifying the liquid glass or glass/ceramic material (54) to form a ceramic component (40) including solid glass or glass/ceramic material (54), the ceramic coating (48) and the porous structure (42), wherein the transfer molding step includes transfer molding the liquid glass or glass/ceramic material (54) at a viscosity of 5 - 15 Pa·s and a molding pressure of 0.5 - 1.5 ksi (3.4 - 10.3 megapascals) to produce a residual void volume of less than one volume percent in the ceramic component (40).


 
2. The method as recited in claim 1, wherein the ceramic coating (48) has a first coefficient of thermal conductivity and the solid glass or glass/ceramic material (54) has a second coefficient of thermal conductivity that is less than the first coefficient of thermal conductivity.
 
3. The method as recited in claim 1 or 2, wherein the ceramic coating (48) is selected from a group consisting of silicon carbide, aluminum nitride, boron nitride, boron phosphide, silicon nitride, beryllium oxide, diamond and combinations thereof and the solid glass or glass/ceramic material (54) comprises a silicate-based glass.
 
4. The method as recited in claim 3, wherein the silicate-based glass comprises an element selected from a group consisting of boron, barium, magnesium, lithium, aluminum and combinations thereof.
 
5. The method as recited in claim 3 or 4, wherein the silicate-based glass includes a nucleating agent.
 
6. The method as recited in any preceding claim, including conducting a heat treatment to produce ceramic phases in the solid glass or glass/ceramic material (54).
 
7. The method of claim 2, wherein the porous structure (42) is a porous fibrous structure (42) that includes, prior to the vapor infiltration, fibers (44) that are coated with a protective coating (44a), the solidifying step comprises cooling the liquid glass or glass/ceramic material (54) and the formed ceramic component (40) includes the solid glass or glass/ceramic material (54), the ceramic coating (48) and the porous fibrous structure (42).
 
8. A ceramic component (40) comprising:

a porous fibrous structure (42) including fibers (44) that are coated with a protective coating (44a);

a ceramic coating (48) on the protective coating (44a) within pores (46) of the porous fibrous structure (42), the ceramic coating (48) and porous fibrous structure (42) defining a residual interconnected porosity (52), wherein the residual porosity is 40-80 volume percent; and

a solid glass or glass/ceramic material (54) within the residual interconnected porosity (52), wherein the component (40) includes a final composition, by volume percentage, of 20-70 of the fibers (44), up to 5 of the protective coating (44a) on the fibers (44), 5-20 of the ceramic coating (48), and a remainder of the solid glass or glass/ceramic material (54) and residual void volume, wherein the residual void volume is less than 1 volume percent.


 
9. The method or ceramic component (40) as recited in claim 7 or 8, wherein the protective coating (44a) is selected from a group consisting of carbon, boron nitride, boron carbide, silicon nitride, silicon carbide, aluminosilicate and combinations thereof, and the ceramic coating (48) is selected from a group consisting of silicon carbide, aluminum nitride, boron nitride, boron phosphide, silicon nitride, beryllium oxide, diamond and combinations thereof.
 
10. The method or ceramic component (40) as recited in any of claims 7 to 9, wherein the final composition includes 30-60 of the fibers (44), 1-2 of the protective coating (44a) on the fibers (44), and 20-40 of the solid glass or glass/ceramic material (54).
 
11. The method or ceramic component (40) as recited in any preceding claim, wherein the liquid glass or glass/ceramic material (54) includes a solid ceramic filler.
 
12. The method or ceramic component (40) as recited in claim 11, wherein the solid ceramic filler includes a silicon-containing material.
 


Ansprüche

1. Verfahren zur Herstellung einer keramischen Komponente (40), wobei das Verfahren das Folgende umfasst:

Verwenden von Dampfinfiltration, um eine Keramikbeschichtung (48) in Poren (46) einer porösen Struktur (42) einzubringen, um einen Vorformling (50) mit vernetzter Restporosität (52) zu bilden, wobei die Restporosität 40-80 Volumenprozent beträgt;

Verwenden von Spritzpressen, um ein erhitztes, flüssiges Glas oder Glas-/Keramikmaterial (54) in die vernetzte Restporosität (52) des Vorformlings (50) einzubringen; und

Härtung des flüssigen Glases oder Glas-/Keramikmaterials (54), um eine keramische Komponente (40) zu bilden, die festes Glas oder Glas-/Keramikmaterial (54), die Keramikbeschichtung (48) und die poröse Struktur (42) beinhaltet, wobei der Spritzpressschritt Spritzpressen des flüssigen Glases oder Glas-/Keramikmaterials (54) bei einer Viskosität von 5-15 Pa·s und eine Presskraft von 0,5-1,5 ksi (3,4-10,3 MPa) beinhaltet, um ein Resthohlvolumen von weniger als einem Volumenprozent in der keramischen Komponente (40) herzustellen.


 
2. Verfahren nach Anspruch 1, wobei die Keramikbeschichtung (48) eine erste Wärmeleitzahl aufweist und das feste Glas oder Glas-/Keramikmaterial (54) eine zweite Wärmeleitzahl aufweist, die geringer ist als die erste Wärmeleitzahl.
 
3. Verfahren nach Anspruch 1 oder 2, wobei die Keramikbeschichtung (48) ausgewählt ist aus einer Gruppe, bestehend aus Siliziumkarbid, Aluminiumnitrid, Bornitrid, Borphosphid, Siliziumnitrid, Berylliumoxid, Diamant und Kombinationen davon, und das feste Glas oder Glas-/Keramikmaterial (54) ein silikatisches Glas umfasst.
 
4. Verfahren nach Anspruch 3, wobei das silikatische Glas ein Element umfasst, das ausgewählt wurde aus einer Gruppe, bestehend aus Bor, Barium, Magnesium, Lithium, Aluminium und Kombinationen davon.
 
5. Verfahren nach Anspruch 3 oder 4, wobei das silikatische Glas einen Keimbildner beinhaltet.
 
6. Verfahren nach einem der vorhergehenden Ansprüche, das eine thermische Behandlung zur Erzeugung von Keramikphasen im festen Glas oder Glas-/Keramikmaterial (54) beinhaltet.
 
7. Verfahren nach Anspruch 2, wobei die poröse Struktur (42) eine poröse Faserstruktur (42) ist, welche vor der Dampfinfiltration, Fasern (44) beinhaltet, die mit einer Schutzschicht (44a) beschichtet sind, wobei der Aushärtungsschritt das Abkühlen des flüssigen Glases oder Glas-/Keramikmaterials (54) umfasst und die gebildete keramische Komponente (40) das feste Glas oder Glas-/Keramikmaterial (54), die Keramikbeschichtung (48) und die poröse Faserstruktur (42) beinhaltet.
 
8. Keramische Komponente (40), das Folgende umfassend:

eine poröse Faserstruktur (42), die Fasern (44) beinhaltet, die mit einer Schutzschicht (44a) beschichtet sind;

eine Keramikbeschichtung (48) auf der Schutzschicht (44a) in Poren (46) der porösen Faserstruktur (42), wobei die Keramikbeschichtung (48) und die poröse Faserstruktur (42) eine vernetzte Restporosität (52) festlegen, wobei die Restporosität 40-80 Volumenprozent beträgt; und

ein festes Glas oder Glas-/Keramikmaterial (54) innerhalb der vernetzten Restporosität (52), wobei die Komponente (40) eine Endzusammensetzung in Volumenprozent von 20-70 der Fasern (44), bis zu 5 der Schutzschicht (44a) auf den Fasern (44), 5-20 der Keramikbeschichtung (48) und einen Rest des festen Glases oder Glas-/Keramikmaterials (54) und Resthohlvolumen beinhaltet, wobei das Resthohlvolumen weniger als 1 Volumenprozent beträgt.


 
9. Verfahren oder keramische Komponente (40) nach Anspruch 7 oder 8, wobei die Schutzschicht (44a) ausgewählt ist aus einer Gruppe, bestehend aus Kohlenstoff, Bornitrid, Borcarbid, Siliziumnitrid, Siliziumcarbid, Alumosilikat und Kombinationen davon, und die Keramikbeschichtung (48) ausgewählt ist aus einer Gruppe, bestehend aus Siliziumcarbid, Aluminiumnitrid, Bornitrid, Borphosphid, Siliziumnitrid, Berylliumoxid, Diamant und Kombinationen davon.
 
10. Verfahren oder keramische Komponente (40) nach den Ansprüchen 7 bis 9, wobei die Endzusammensetzung 30-60 der Fasern (44), 1-2 der Schutzschicht (44a) auf den Fasern (44) und 20-40 des festen Glases oder Glas-/Keramikmaterials (54) beinhaltet.
 
11. Verfahren oder keramische Komponente (40) nach einem der vorhergehenden Ansprüche, wobei das flüssige Glas oder Glas-/Keramikmaterial (54) einen festen keramischen Füllstoff beinhaltet.
 
12. Verfahren oder keramische Komponente (40) nach Anspruch 11, wobei der feste keramische Füllstoff ein siliziumhaltiges Material beinhaltet.
 


Revendications

1. Procédé de fabrication d'un composant céramique (40), le procédé comprenant :

l'utilisation d'une infiltration de vapeur pour déposer un revêtement céramique (48) à l'intérieur des pores (46) d'une structure poreuse (42) pour former un corps de préforme (50) ayant une porosité interconnectée résiduelle (52), dans laquelle la porosité résiduelle est de 40 à 80 pour cent en volume ;

l'utilisation d'un moulage par transfert pour déposer un matériau de verre ou de verre/céramique (54) liquide chauffé à l'intérieur de la porosité interconnectée résiduelle (52) du corps de préforme (50) ; et

la solidification du matériau de verre ou de verre/céramique (54) liquide pour former un composant céramique (40) comprenant un matériau de verre ou de verre/céramique (54) solide, le revêtement céramique (48) et la structure poreuse (42), dans lequel l'étape de moulage par transfert comprend le moulage par transfert du matériau de verre ou de verre/céramique (54) liquide à une viscosité de 5 à 15 Pa.s et à une pression de moulage de 0,5 à 1,5 ksi (3,4 à 10,3 mégapascals) pour produire un volume vide résiduel de moins d'un pour cent en volume dans le composant céramique (40).


 
2. Procédé selon la revendication 1, dans lequel le revêtement céramique (48) présente un premier coefficient de conductivité thermique et le matériau de verre ou de verre/céramique (54) solide présente un second coefficient de conductivité thermique qui est inférieur au premier coefficient de conductivité thermique.
 
3. Procédé selon la revendication 1 ou 2, dans lequel le revêtement céramique (48) est sélectionné dans un groupe constitué du carbure de silicium, du nitrure d'aluminium, du nitrure de bore, du phosphure de bore, du nitrure de silicium, de l'oxyde de béryllium, du diamant et de leurs combinaisons et le matériau de verre ou de verre/céramique (54) solide comprend un verre à base de silicate.
 
4. Procédé selon la revendication 3, dans lequel le verre à base de silicate comprend un élément sélectionné dans un groupe constitué du bore, du baryum, du magnésium, du lithium, de l'aluminium et de leurs combinaisons.
 
5. Procédé selon la revendication 3 ou 4, dans lequel le verre à base de silicate comprend un agent de nucléation.
 
6. Procédé selon une quelconque revendication précédente, comprenant la mise en oeuvre d'un traitement thermique pour produire des phases céramiques dans le matériau de verre ou de verre/céramique (54) solide.
 
7. Procédé selon la revendication 2, dans lequel la structure poreuse (42) est une structure fibreuse poreuse (42) qui comprend, avant l'infiltration de vapeur, des fibres (44) qui sont revêtues avec un revêtement protecteur (44a), l'étape de solidification comprend le refroidissement du matériau de verre ou de verre/céramique (54) liquide et le composant céramique (40) formé comprend le matériau de verre ou de verre/céramique (54) solide, le revêtement céramique (48) et la structure fibreuse poreuse (42).
 
8. Composant céramique (40) comprenant :

une structure fibreuse poreuse (42) comprenant des fibres (44) qui sont revêtues avec un revêtement protecteur (44a) ;

un revêtement céramique (48) sur le revêtement protecteur (44a) à l'intérieur des pores (46) de la structure fibreuse poreuse (42), le revêtement céramique (48) et la structure fibreuse poreuse (42) définissant une porosité interconnectée résiduelle (52), dans laquelle la porosité résiduelle est de 40 à 80 pour cent en volume ; et

un matériau de verre ou de verre/céramique (54) solide à l'intérieur de la porosité interconnectée résiduelle (52), dans lequel le composant (40) comprend une composition finale, en pourcentage en volume, de 20 à 70 des fibres (44), jusqu'à 5 du revêtement protecteur (44a) sur les fibres (44), 5 à 20 du revêtement céramique (48), et le reste étant le matériau de verre ou de verre/céramique (54) solide et le volume vide résiduel, dans lequel le volume vide résiduel est inférieur à 1 pour cent en volume.


 
9. Procédé ou composant céramique (40) selon la revendication 7 ou 8, dans lequel le revêtement protecteur (44a) est sélectionné dans un groupe constitué du carbone, du nitrure de bore, du carbure de bore, du nitrure de silicium, du carbure de silicium, d'un aluminosilicate et de leurs combinaisons, et le revêtement céramique (48) est sélectionné dans un groupe constitué du carbure de silicium, du nitrure d'aluminium, du nitrure de bore, du phosphure de bore, du nitrure de silicium, de l'oxyde de béryllium, du diamant et de leurs combinaisons.
 
10. Procédé ou composant céramique (40) selon l'une quelconque des revendications 7 à 9, dans lequel la composition finale comprend 30 à 60 des fibres (44), 1 à 2 du revêtement protecteur (44a) sur les fibres (44), et 20 à 40 du matériau de verre ou de verre/céramique (54) solide.
 
11. Procédé ou composant céramique (40) selon une quelconque revendication précédente, dans lequel le matériau de verre ou de verre/céramique (54) liquide comprend un agent céramique solide de remplissage.
 
12. Procédé ou composant céramique (40) selon la revendication 11, dans lequel l'agent céramique solide de remplissage comprend un matériau contenant de la silice.
 




Drawing






REFERENCES CITED IN THE DESCRIPTION



This list of references cited by the applicant is for the reader's convenience only. It does not form part of the European patent document. Even though great care has been taken in compiling the references, errors or omissions cannot be excluded and the EPO disclaims all liability in this regard.

Patent documents cited in the description