IE903908A1 - Ceramic coatings, process for the manufacture of the said¹coatings and substrates thus coated - Google Patents
Ceramic coatings, process for the manufacture of the said¹coatings and substrates thus coatedInfo
- Publication number
- IE903908A1 IE903908A1 IE390890A IE390890A IE903908A1 IE 903908 A1 IE903908 A1 IE 903908A1 IE 390890 A IE390890 A IE 390890A IE 390890 A IE390890 A IE 390890A IE 903908 A1 IE903908 A1 IE 903908A1
- Authority
- IE
- Ireland
- Prior art keywords
- ceramic
- precursor
- process according
- coatings
- coating
- Prior art date
Links
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 11
- 238000005524 ceramic coating Methods 0.000 title claims abstract description 6
- 239000000758 substrate Substances 0.000 title claims description 24
- 238000000034 method Methods 0.000 title claims description 17
- 238000000576 coating method Methods 0.000 claims abstract description 37
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 26
- 239000000919 ceramic Substances 0.000 claims abstract description 24
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000002243 precursor Substances 0.000 claims description 26
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 21
- 229910052757 nitrogen Inorganic materials 0.000 claims description 15
- 239000011248 coating agent Substances 0.000 claims description 14
- 229910052751 metal Inorganic materials 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims description 8
- 239000000203 mixture Substances 0.000 claims description 8
- 239000012700 ceramic precursor Substances 0.000 claims description 7
- 238000000197 pyrolysis Methods 0.000 claims description 7
- 229910052710 silicon Inorganic materials 0.000 claims description 7
- 150000002739 metals Chemical class 0.000 claims description 6
- 239000010703 silicon Substances 0.000 claims description 6
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 5
- 229910052760 oxygen Inorganic materials 0.000 claims description 5
- 239000001301 oxygen Substances 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 4
- 229910052719 titanium Inorganic materials 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 3
- 229910052796 boron Inorganic materials 0.000 claims description 3
- 238000000151 deposition Methods 0.000 claims description 3
- 229910052735 hafnium Inorganic materials 0.000 claims description 3
- 239000007788 liquid Substances 0.000 claims description 3
- 229910052750 molybdenum Inorganic materials 0.000 claims description 3
- -1 polysiloxazanes Polymers 0.000 claims description 3
- 239000011819 refractory material Substances 0.000 claims description 3
- 229910052715 tantalum Inorganic materials 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 229910052720 vanadium Inorganic materials 0.000 claims description 3
- 229910052776 Thorium Inorganic materials 0.000 claims description 2
- 239000006185 dispersion Substances 0.000 claims description 2
- 229910052747 lanthanoid Inorganic materials 0.000 claims description 2
- 150000002602 lanthanoids Chemical class 0.000 claims description 2
- 229910052746 lanthanum Inorganic materials 0.000 claims description 2
- 229920000548 poly(silane) polymer Polymers 0.000 claims description 2
- 229920003257 polycarbosilane Polymers 0.000 claims description 2
- 229920001709 polysilazane Polymers 0.000 claims description 2
- 229910052727 yttrium Inorganic materials 0.000 claims description 2
- 229910004298 SiO 2 Inorganic materials 0.000 claims 1
- 230000008021 deposition Effects 0.000 claims 1
- 238000010438 heat treatment Methods 0.000 abstract description 8
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 8
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 6
- OAKJQQAXSVQMHS-UHFFFAOYSA-N Hydrazine Chemical compound NN OAKJQQAXSVQMHS-UHFFFAOYSA-N 0.000 description 4
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 229910052681 coesite Inorganic materials 0.000 description 4
- 229910052906 cristobalite Inorganic materials 0.000 description 4
- 229910003465 moissanite Inorganic materials 0.000 description 4
- 229910010271 silicon carbide Inorganic materials 0.000 description 4
- 239000000377 silicon dioxide Substances 0.000 description 4
- 235000012239 silicon dioxide Nutrition 0.000 description 4
- 229910052682 stishovite Inorganic materials 0.000 description 4
- 229910052905 tridymite Inorganic materials 0.000 description 4
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 239000011651 chromium Substances 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 125000004430 oxygen atom Chemical group O* 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 229910052581 Si3N4 Inorganic materials 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- 239000012298 atmosphere Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 229910052748 manganese Inorganic materials 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000012299 nitrogen atmosphere Substances 0.000 description 2
- 238000011017 operating method Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000002904 solvent Substances 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- VZSRBBMJRBPUNF-UHFFFAOYSA-N 2-(2,3-dihydro-1H-inden-2-ylamino)-N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]pyrimidine-5-carboxamide Chemical compound C1C(CC2=CC=CC=C12)NC1=NC=C(C=N1)C(=O)NCCC(N1CC2=C(CC1)NN=N2)=O VZSRBBMJRBPUNF-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 239000005046 Chlorosilane Substances 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 239000012300 argon atmosphere Substances 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- KOPOQZFJUQMUML-UHFFFAOYSA-N chlorosilane Chemical compound Cl[SiH3] KOPOQZFJUQMUML-UHFFFAOYSA-N 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 229910052593 corundum Inorganic materials 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 125000004435 hydrogen atom Chemical class [H]* 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 1
- 239000012705 liquid precursor Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 150000003141 primary amines Chemical class 0.000 description 1
- 238000010926 purge Methods 0.000 description 1
- 229920002050 silicone resin Polymers 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- 229910001845 yogo sapphire Inorganic materials 0.000 description 1
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
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5053—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials non-oxide ceramics
- C04B41/5057—Carbides
- C04B41/5059—Silicon carbide
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
- C04B41/87—Ceramics
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Ceramic Products (AREA)
- Paints Or Removers (AREA)
- Chemical Vapour Deposition (AREA)
- Application Of Or Painting With Fluid Materials (AREA)
- Cookers (AREA)
Abstract
Ceramic coatings. These coatings can be employed especially in the production of heating enclosures. These coatings consist of a siliceous ceramic containing free carbon.
Description
The present invention, made in the laboratories of the Applicant Company and of the company Procelis S.A., relates to ceramic coatings intended especially for improving heat transfers, a process for the manufacture of the said coatings and to the substrates bearing the said coatings.
W. Bauer and R. Steinhardt (Freiberg Forschungsh 10 A, A 738, 8-14 1986) showed that some Fe2O3 or SiC coatings were capable of improving the thermal efficiency of ovens and of thus reducing their energy consumption.
The effect of a zirconia-based coating has also 15 been described by J. Hollander (Iron & Steel Engineer,
p. 40, June 1987) and by J. Clements (Heat Treatment of Metals 1986.3.p 76).
A. Fukuda and M. Maki (Japanese Patent Application 60/251,185) produced coatings with the aid of a toluene solution of borosiloxane filled with ZrO2, TiO2, A12O3, SiO2 and/or CeO2, SiC and Si3N4 powders, this solution being applied like a paint.
K. Shioya (EP-A-0,117,935) applied by spraying an aqueous solution of potassium silicate filled with various powdered ceramics.
A. Fukuda, 7. Kameka and M. Maki (Japanese Patent
Application 61/149,740) employed a suspension of Si,
Ti, Al, Zr, Fe, Mn, Cu, Co and Ni oxides in a silicone resin/b-il.
S. Mitsumoto, T. Nishimori and K. Kanayama have described coatings based on alkali metal hydroxides (Japanese Patent Application 60/228,683).
C. Wickersham and E. Foster (USP 4,414,085) have described processes for vapour-phase deposition of a layer of carbon onto a substrate, by starting with a carbide of at least one element chosen from the group consisting of Si, B, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and
W, and of a hydrocarbon gas capable of being decomposed into carbon and hydrogen, such as acetylene.
M. Maki, Y. Kaneko, A. Fukuda and M. Isoya (Japanese Patent Application 62/167,271) have described a coating on ceramic or on metal, made up of a binder crosslinked into polytitanocarboxysilane, of ZrO2, as principal additive, of SiO2, Al2O3 or TiO2 and of an Fe, Mn, Cu, Ni or Co oxide, this composition being used in a solvent phase (toluene + N-methylpyrrolidone).
T. Kawachi and C. Okamoto (Japanese Patent
Application 62/256,875) have proposed coating compositions comprising a silicone resin in combination with a ceramic powder and various additives such as ZrO2, TiO2, MnO2, Fe2(SO*)3 and CrO2.
In what precedes, the numbers shown in the case of the Japanese patent applications are the numbers of the applications published before examination.
The invention proposes coatings capable especially of being employed in the production of enclosures intended to be heated to an elevated temperature, such as ovens (without the scope of the invention being limited by this indication), these coatings permitting an excellent heat transfer between the heating element and the articles to be heated.
The invention also proposes coatings enabling the desired temperature to be attained more rapidly (when compared with the absence of coating).
The invention further proposes coatings resulting in a greater homogeneity of the temperature in the enclosure (same remark as above).
The invention further proposes coatings simultaneously permitting energy savings and an increase in production efficiency and in quality.
Other advantages of the coatings in accordance with the invention will become apparent on reading what follows.
The coatings in accordance with the invention are characterized in that they comprise an essentially unoxidized ceramic containing free carbon.
The invention relates more specifically to coatings containing a ceramic containing from 2 to 40 % by weight of free carbon.
The expression essentially unoxidized means that the ceramic has a combined oxygen content lower than % by weight, that is to say that the said ceramic is essentially carbided or nitrided.
More precisely, the ceramics forming the coatings in accordance with the invention consist of silicon and of carbon and optionally of nitrogen and/or oxygen [within the conditions defined above] and/or one or more metals .
The metal(s) referred to above may be chosen especially from the group consisting of B, Al, Ti, V, Cr, Zr, Mo, Hf, Ta, W, Y, Th, La and the metals of the lanthanide series.
Within the meaning of the invention, the 10 expression free carbon refers to carbon atoms bonded to other carbon atoms, that is to say it excludes the carbon atoms bonded exclusively to other elements and especially to silicon, nitrogen and oxygen atoms. The percentage of free carbon (by weight) is defined by the equation
C % (by weight) = Mq χ CBV χ 100 / 4 χ Mj CBT denoting the number of moles of valencies of carbon atoms bonded to other carbon atoms Me denoting the molecular mass of carbon
Ms denoting the mass of the sample.
To determine a percentage of free carbon of a ceramic which has a given overall elemental composition, it will be assumed that ail the valencies of the nitrogen and oxygen atoms, when there are any, are bonded to the silicon atoms and that all the silicon valencies are bonded to carbon atoms and, if appropriate, nitrogen and/or oxygen atoms.
Another subject of the invention is a process for t_ the manufacture of the abovementioned coatings, this process being characterized in that it consists in depositing a ceramic precursor onto the substrate and in then causing the formation, on the said substrate, of a coating consisting of a ceramic having the characteristics referred to above.
The ceramic precursor may be chosen from a large group of products, provided that these precursors generate ceramics containing free carbon.
Among these precursors those mentioned foremost will be the silicon-based precursors and especially polysilazanes, polysiloxazanes, polycarbosilanes and polysilanes, that is to say products containing at least silicon and carbon and, if appropriate, nitrogen and/or oxygen.
The preparation of these ceramic precursors is known and does not in itself form a subject of the invention. Reference may be made especially to French Patents and Patent Applications Nos. 87/18,215,
88/08,384 and 88/10,952, the content of which is incorporated by reference. Purely by way of illustration, mention will be made simply of the precursors obtained by reaction of an optionally organosubstituted halosilane with a nitrogenous compound, and especially with ammonia, an amine and in particular a primary amine, a hydrazine and optionally water. It is obviously also possible to employ mixtures of the abovementioned nitrogenous compounds during the preparation of the precursors, and mixtures of precursors, with a view to the preparation of the ceramics .
Among these precursors preference is given in the 5 invention to the products resulting in ceramics containing the proportion of free carbon referred to above and exhibiting the following elemental composition (by weight): Si: 30 to 70 %, C: 5 to 35 %, N: 2 to 30 %, 0: 0 to 15 % (independently of the metals which may be present), the abovementioned elements being essentially combined in the form of Si3N4, SiC and SiO2, independently of the free carbon.
The application of the ceramic precursors to the substrate to be coated can be performed in various ways, bearing in mind in particular the physical state of the said precursors and the nature of the substrates. When liquid precursors are involved, for example below 50C, they can be applied directly by following the methods for applying paints, that is to say with a brush, with a spatula or by spraying, with or without the use of solvent or diluent. When precursors which are solid in the same temperature range are involved, they can be applied in the form of solution or dispersion or can be used by spraying in powdered form in a flame capable of softening the product.
In general, and provided that the physical state of the precursor permits it, the application of the precursors in the pure state (as they are) onto porous substrates will be recommended, the nonporous substrates being preferably impregnated by starting with a solution of precursor.
In the case of the precursors capable of degrading in contact with air, it would be advisable to use them under inert atmosphere, for example a nitrogen or argon atmosphere. The precursors may be deposited once or a number of times, separated by a pyrolysis of the preceding coating.
The coating thickness may vary within wide limits. Purely by way of indication, this thickness can range from 1 vm to 1 mm.
These coatings can be applied onto substrates of 15 various natures. Examples of such coatings which will be mentioned especially are metallic substrates, especially of steel, the substrates consisting of refractory materials, in particular the substrates based on ceramic fibres, it being possible for the said fibres to be especially silicoaluminous fibres generally containing 45 to 60 % of alumina and, where appropriate, chromium, or else polycrystalline fibres with a high alumina content (for example between 72 and 94 %) .
The precursors forming the coating of the abovementioned substrates can be pyrolysed to ceramic by heating to a temperature which is generally at least equal to 800 *C and in most cases higher than 900*C, it being possible for the maximum temperature to reach 1250’C, or even more. As a general rule, this pyrolysis is carried out under inert atmosphere, such as a nitrogen atmosphere.
The coatings in accordance with the invention and the substrates bearing these coatings, which also form a subject of the invention, can be employed in the manufacture of various materials, and in particular of enclosures intended to be heated to elevated 10 temperatures, for example ovens, it being possible for the said temperature to go up to 1200*C.
The use of these coatings, over all or part of the surfaces forming the said enclosure makes it possible to improve substantially the heat transfer between the heating element (enclosure wall) and the article to be heated.
Furthermore, a faster temperature rise and a better uniformity of this temperature are observed, in relation to unheated walls.
The following examples illustrate the invention.
EXAMPLE 1
1) Ceramic precursor (Px):
A polysiloxazane is employed, obtained by reaction of hydrazine, chlorosilane and water In accordance with the operating method described in French Patent Application No. 87/18,215 (Example 8).
The precursor Px is a viscous liquid at room temperature and is used as it is with the aid of a spatula.
2) Substrate;
The substrate consists of small fibrous refractory plates of the silicoaluminous materials group (product marketed under the trademark Procelit 160® by Procelis).
3) Application:
The precursor PL is applied onto the abovementioned small plates, 100 mm χ 40 mm χ 10 mm in size (deposited weight: approximately 500 g/ra2). This application is made under a dry nitrogen stream.
The small coated plates are fired at 1000’C under nitrogen purging (temperature rise of 100*C per hour, followed by a plateau of one hour at 1000*C and then natural cooling under nitrogen).
After cooling, the small plates are immersed for 24 hours in water at 20*C and are then dried under vacuum in an oven (temperature: 80*C).
The ceramic obtained during this pyrolysis 20 exhibits the following composition: Si: approximately
44.3 %, C: approximately 28.7 %, N: approximately 19.1 % and 0: approximately 5.1 %, and a free carbon content of 24 %, the constituents being combined as Si3Nt (47.75 %), SiO2 (9.6 %) and SiC (16 %).
4) Manufacture of enclosures:
Two enclosures approximately 1 litre in capacity are produced, the side walls of which are made, the first with 10 small plates 100 χ 40 χ 10 mm made of
Procelit 160® and the second with 10 identical small plates, the whole of their surface being coated by means of the ceramic described above.
A charge equipped at its centre with a 5 thermocouple which allows its temperature rise to be followed is placed in each of the chambers.
The two chambers are placed symmetrically in a fast-heating electrical oven, whose temperature is also followed using a thermocouple.
The course of the temperature rise of the oven (FJ, of the charge placed in the enclosure bearing the surfaces coated in accordance with the invention (Cx), and of the charge placed in the uncoated enclosure as a control (TJ , is shown on the curve of Figure 1, where e’C denotes the temperature and min the time.
It is found that at the end of a given oven heating period the temperature of the charge Cx is always higher than that of the control Tt, it being possible for this temperature difference to reach 50*C.
Similarly, it is found that a given temperature is always attained more rapidly by the charge Cx than by the charge Tx, which demonstrates the effectiveness of the coating in accordance with the invention.
EXAMPLE 2
The substrate and the manufacture of the enclosure are the same as in Example 1.
The ceramic precursor (P2) is a polysiloxazane obtained by following the operating method described in
Frencte-Patent Application No. 87/18,215 (Example 4).
This precursor P2 is a viscous liquid, applied onto the substrate as it is (weight deposited: approximately 370 g/m2).
After firing at 1000 C under the conditions described above, followed by cooling, the impregnation of the substrate (thus bearing a first layer of ceramic coating) with the precursor P2 is repeated once, still under a nitrogen stream.
The ceramic resulting from the above pyrolyses exhibits the following approximate composition: Si: approximately 52.5 %, C: approximately 15.1 %, N: approximately 22.7 % and 0: approximately 9.2 %, and a free carbon content of approximately 10.6 %, the elements being combined as Si3N4: 56.75, SiO2: 17.3 and SiC: 14.8.
Figure 2 makes it possible to follow the change in the temperature of the oven (F2), of the charge placed in the coated enclosure (C2) and of the charge placed in the control enclosure (T2), β *C denoting the temperature and min the time.
A substantial delay is observed in the temperature rise of the charge T2 relative to the charge C2 and, in the case of a given oven heating period, a value of the charge temperature T2 which is lower (sometimes up to 80 *C) than the temperature reached by the charge C2, which confirms the effectiveness of the coating in accordance with the invention.
Claims (18)
1. Ceramic coating characterized in that it comprises an essentially unoxidized ceramic containing free carbon.
2. Coating according to Claim 1, characterized in that it comprises a ceramic containing 2 to 40 % by weight of free carbon, defined by the equation C % (by weight) = Me χ C BV χ 100 / 4 χ Mg C BV denoting the number of moles of valencies of carbon atoms bonded to other carbon atoms Me denoting the molecular mass of carbon Mg denoting the mass of the sample.
3. Coating according to either of Claims 1 to 2, characterized in that the ceramic consists essentially of silicon and of carbon and optionally of nitrogen and/or oxygen, the content of oxygen bonded to the other components being lower than 25 % by weight.
4. Coating according to Claim 3, characterized in that the ceramic additionally contains at least one metal chosen from the group consisting of B, Al, Ti, V, Cr, Zr, Mo, Hf, Ta, W, Y, Th, La and the metals of the lanthanide series.
5. Coating according to any one of Claims 1 to 4, characterized in that the ceramic has the following elemental composition: Si: 30 to 70 %, C: 5 to 35 %, N: 2 to 30 %, 0: 0 to 15 %, combined essentially in the form of Si 3 N M SiC and SiO 2 , independently of the free carbon. y_
6. Process for the manufacture of coatings according to any one of Claims 1 to 5, by depositing a ceramic precursor onto a substrate and then forming the ceramic by pyrolysis of the said precursor on the substrate.
7. Process according to Claim 6, characterized in that the precursor is chosen from the group consisting of polysilazanes, polysiloxazanes, polycarbosilanes and polysilanes.
8. Process according to either of Claims 6 and 7, characterized in that the precursor is applied in the liquid state.
9. Process according to any one of Claims S to 8, characterized in that the precursor is applied in the form of solution or dispersion.
10. Process according to any one of Claims 6 to 9, characterized in that the precursor layer has a thickness of between 1 M m and 1 mm.
11. Process according to Claim 10, characterized in that the thickness is obtained using a number of successive depositions of the precursor, which are separated by a pyrolysis of the said precursor.
12. Process according to any one of Claims 6 to 11, characterized in that the pyrolysis is carried out at a temperature of at least 800*C.
13. Process according to Claim 12, characterized in that the pyrolysis is carried out at a temperature of between 900 and 1250*C.
14. Process according to any one of Claims 6 to 13, characterized in that the substrate is chosen from the group consisting of metals and refractory materials.
15. Process according to Claim 14, characterized in that the refractory material is based on ceramic fibres of the silicoaluminous group.
16. Substrate bearing a coating according to any one of Claims 1 to 5.
17. A ceramic coating according to any preceding claim substantially as hereinbefore described and exemplified.
18. A process for the manufacture of coatings according to any preceding claim substantially as hereinbefore described and exemplified.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8914276 | 1989-10-31 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| IE903908A1 true IE903908A1 (en) | 1991-05-08 |
Family
ID=9386965
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| IE390890A IE903908A1 (en) | 1989-10-31 | 1990-10-30 | Ceramic coatings, process for the manufacture of the said¹coatings and substrates thus coated |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0426529A1 (en) |
| JP (1) | JPH03193683A (en) |
| KR (1) | KR910007837A (en) |
| CN (1) | CN1051343A (en) |
| AU (1) | AU641191B2 (en) |
| CA (1) | CA2028993A1 (en) |
| IE (1) | IE903908A1 (en) |
| NO (1) | NO904710L (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100927548B1 (en) * | 2008-01-29 | 2009-11-20 | 주식회사 티씨케이 | Metal with ceramic coating on its surface and its manufacturing method |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5519508A (en) * | 1978-07-28 | 1980-02-12 | Tokushu Muki Zairyo Kenkyusho | Preparation of heattproof oxidationnresisting material |
| JPS5567585A (en) * | 1978-11-13 | 1980-05-21 | Tokushu Muki Zairyo Kenkyusho | Manufacture of corrosionnresistant* heattresistant and acid resistant molded body |
| JPS5971362A (en) * | 1982-10-15 | 1984-04-23 | Toagosei Chem Ind Co Ltd | Composition for curing |
| US4618591A (en) * | 1983-11-09 | 1986-10-21 | Sony Corporation | Silicon carbide-carbon composite molded product and process for manufacturing the same |
| JPS60134126A (en) * | 1983-12-23 | 1985-07-17 | Matsushita Electric Ind Co Ltd | Far infrared ray radiant material |
| JPS60251185A (en) * | 1984-05-25 | 1985-12-11 | 松下電器産業株式会社 | Radiator |
| JPS61149740A (en) * | 1984-12-21 | 1986-07-08 | Matsushita Electric Ind Co Ltd | radiant |
| US4857395A (en) * | 1987-10-08 | 1989-08-15 | The Standard Oil Company | Graphite composites and process for the manufacture thereof |
| FR2625211A1 (en) * | 1987-12-28 | 1989-06-30 | Atochem | POLYSILOXAZANES, PROCESS FOR THE PREPARATION THEREOF, USE THEREOF AS PRECURSORS OF CERAMICS AND CERAMIC DISHES |
| JPH01221466A (en) * | 1988-03-01 | 1989-09-04 | Toa Nenryo Kogyo Kk | Coating composition and coating method |
| FR2629814B1 (en) * | 1988-04-06 | 1991-03-22 | Aerospatiale | PROCESS FOR THE PRODUCTION OF A COMPOSITE CERAMIC MATERIAL WITH FIBROUS STRUCTURE AND MATERIAL THUS OBTAINED |
-
1990
- 1990-10-24 EP EP90402990A patent/EP0426529A1/en not_active Withdrawn
- 1990-10-25 JP JP2288264A patent/JPH03193683A/en active Pending
- 1990-10-30 AU AU65614/90A patent/AU641191B2/en not_active Ceased
- 1990-10-30 NO NO90904710A patent/NO904710L/en unknown
- 1990-10-30 IE IE390890A patent/IE903908A1/en unknown
- 1990-10-30 CA CA002028993A patent/CA2028993A1/en not_active Abandoned
- 1990-10-31 CN CN90108761A patent/CN1051343A/en active Pending
- 1990-10-31 KR KR1019900017619A patent/KR910007837A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| NO904710L (en) | 1991-05-02 |
| EP0426529A1 (en) | 1991-05-08 |
| JPH03193683A (en) | 1991-08-23 |
| AU6561490A (en) | 1991-05-09 |
| CA2028993A1 (en) | 1991-05-01 |
| KR910007837A (en) | 1991-05-30 |
| NO904710D0 (en) | 1990-10-30 |
| AU641191B2 (en) | 1993-09-16 |
| CN1051343A (en) | 1991-05-15 |
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