CN112537962B - Preparation method of SiC coating - Google Patents
Preparation method of SiC coating Download PDFInfo
- Publication number
- CN112537962B CN112537962B CN202011453458.4A CN202011453458A CN112537962B CN 112537962 B CN112537962 B CN 112537962B CN 202011453458 A CN202011453458 A CN 202011453458A CN 112537962 B CN112537962 B CN 112537962B
- Authority
- CN
- China
- Prior art keywords
- coating
- sic
- powder
- temperature
- preparing
- 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.)
- Active
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
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
- C04B35/56—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
- C04B35/565—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
- C04B35/571—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide obtained from Si-containing polymer precursors or organosilicon monomers
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/62222—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products obtaining ceramic coatings
-
- 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
- C04B41/5062—Borides, Nitrides or Silicides
-
- 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
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/38—Non-oxide ceramic constituents or additives
- C04B2235/3817—Carbides
- C04B2235/3826—Silicon carbides
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/38—Non-oxide ceramic constituents or additives
- C04B2235/3817—Carbides
- C04B2235/3839—Refractory metal carbides
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/38—Non-oxide ceramic constituents or additives
- C04B2235/3817—Carbides
- C04B2235/3839—Refractory metal carbides
- C04B2235/3843—Titanium carbides
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/38—Non-oxide ceramic constituents or additives
- C04B2235/3852—Nitrides, e.g. oxynitrides, carbonitrides, oxycarbonitrides, lithium nitride, magnesium nitride
- C04B2235/3886—Refractory metal nitrides, e.g. vanadium nitride, tungsten nitride
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/40—Metallic constituents or additives not added as binding phase
- C04B2235/404—Refractory metals
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/50—Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
- C04B2235/54—Particle size related information
- C04B2235/5418—Particle size related information expressed by the size of the particles or aggregates thereof
- C04B2235/5436—Particle size related information expressed by the size of the particles or aggregates thereof micrometer sized, i.e. from 1 to 100 micron
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
- C04B2235/6562—Heating rate
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/656—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes characterised by specific heating conditions during heat treatment
- C04B2235/6567—Treatment time
-
- 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
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/65—Aspects relating to heat treatments of ceramic bodies such as green ceramics or pre-sintered ceramics, e.g. burning, sintering or melting processes
- C04B2235/658—Atmosphere during thermal treatment
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Ceramic Products (AREA)
Abstract
The invention discloses a preparation method of a SiC coating, which adopts polymethyl silane as a coating main body material, and the prepared coating slurry can be used for preparing the SiC high-temperature resistant coating on a high-density blank by adopting a brushing method through adding active metal powder and inert ceramic powder, and the coating has the characteristics of compactness, high bonding strength, high temperature resistance and oxidation resistance. The SiC high-temperature resistant coating prepared by the method of the invention has compact structure, high bonding strength with a high-density blank, difficult shedding and cracking of the coating and good oxidation resistance below 1600 ℃. The method has the advantages of low requirement on equipment, short manufacturing period, high efficiency and safe and controllable preparation process. Meanwhile, the prepared SiC coating has high bonding strength with a high-density blank, is compact, is not easy to fall off, has oxidation resistance, and can meet the requirement of high-temperature resistance and oxidation resistance at 1600 ℃.
Description
Technical Field
The invention belongs to the technical field of coating preparation, and particularly relates to a preparation method of a SiC coating.
Background
With the rapid development of modern science and technology, industrial production puts more and more requirements on structural materials, such as the requirement on the performance of high-temperature oxidation resistance, corrosion resistance, temperature shock resistance, scouring resistance and the like.
Silicon carbide is a compound with extremely strong covalent bonds, and still keeps higher bonding strength under high temperature conditions. The structural characteristics of silicon carbide determine a series of excellent performances of the silicon carbide, such as high strength, high temperature resistance, oxidation resistance, excellent chemical stability and corrosion resistance of most acid-base solutions.
At present, the preparation method of the SiC coating mainly comprises Si-C in-situ reaction, chemical vapor deposition and the like. The Si-C in-situ reaction is generally carried out at 1500-1700 ℃, silicon carbide is produced by reaction by utilizing the fluidity of silicon liquid and the contact of steam silicon and carbon, the SiC coating prepared by the method is simple to operate, but the uniformity of the thickness of the coating is difficult to control, and residual silicon is left, so that the corrosion resistance and the high-temperature oxidation resistance of the coating are influenced. The silicon carbide coating prepared by the vapor deposition method is mainly prepared by depositing trichloromethylsilane at about 1100 ℃ for hundreds of hours by taking hydrogen or argon as carrier gas, and finally obtaining the silicon carbide coating with tight combination and excellent performance. However, trichloromethylsilane is corrosive, flammable and explosive, and generates a large amount of HCl gas in the deposition process, and the reaction temperature is about 1100 ℃, so that the requirements on equipment and environment are strict, the manufacturing period is long, and the cost is high. At present, the direct preparation of SiC high-temperature resistant coatings by a brushing method is less, and the coatings prepared by the brushing method are mostly applied to low-density porous materials, such as low-density carbon felts. As for the high-density material, for example, the high-density graphite member and the carbon member, Si-C in-situ reaction and chemical vapor deposition are generally used. When the coating is prepared on the high-density blank by the brushing method, the bonding strength of the coating is not enough and the coating is easy to fall off.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention aims to provide a preparation method of a SiC coating.
The invention relates to a preparation method of a SiC coating, which comprises the following steps:
step one, pre-coating treatment
Vacuum dipping, curing and drying a substrate by adopting a dipping agent to obtain a precoated substrate, wherein the dipping agent contains polymethyl silane;
step two, preparation of coating slurry
Mixing polymethyl silane, divinyl benzene (DVB) and metal powder to obtain a mixture, adding ceramic powder into the mixture, and mixing to obtain coating slurry;
step three, preparation of coating
And (4) coating the coating slurry obtained in the step two on the surface of the substrate subjected to the pre-coating treatment obtained in the step one, drying and sintering to obtain the coating.
According to the preparation method of the SiC coating provided by the invention, the polymethyl silane is used as a coating main body material, the active metal powder and the inert ceramic powder are added, the prepared coating slurry can be used for preparing the SiC high-temperature resistant coating on a high-density blank by adopting a brushing method, and the coating has the characteristics of compactness, high bonding strength, high temperature resistance and oxidation resistance.
In order to solve the problem of bonding strength between the SiC coating prepared by the coating method and a high-density green body, the green body is subjected to vacuum impregnation by the polymethylsilane, and after the impregnation is finished, the surface of the green body is cured to form a polymethylsilane film coating so as to provide interface conditions for the subsequent bonding of coating slurry and the green body. And secondly, sintering the polymethyl silane to form the high-temperature-resistant and antioxidant SiC. In addition, in the aspect of coating slurry preparation, the coating has more excellent high-temperature-resistant oxidation resistance by adding high-temperature-resistant powder such as ZrC, ZrN, Ti powder, Zr powder and the like, and in the aspect of coating densification, the coating can not shrink and generate microcracks in the whole coating sintering process by adjusting the proportion of polymethyl silane, active filler, inert filler and solvent, so that the dense oxidation-resistant coating is obtained.
The inventor finds that in the process of preparing the slurry, the order of powder feeding needs to be well controlled, metal powder is added firstly, and is uniformly mixed with polymethylsilane and divinylbenzene, and then ceramic powder is added, because the metal powder belongs to active filler, and is added to react with the polymethylsilane, and can promote the crosslinking of the polymethylsilane and DVB, so that the viscosity and the dispersibility are increased, the ceramic powder is inert filler, if the ceramic powder is added together with the metal powder, the reaction of the metal powder is inhibited, the crosslinking of the polymethylsilane and DVB is reduced, the dispersion effect is influenced, and even powder agglomeration is generated.
Preferably, in the first step, the substrate is selected from a graphite material or a carbon/carbon composite material.
In the present invention, the graphite material or the carbon/carbon composite material as the substrate is a high-density green body.
Preferably, in the first step, the vacuum impregnation time is 30-120 min, and the vacuum degree is controlled below 20 Pa.
During the immersion process, the polymethylsilane is flooded out of the substrate.
Preferably, in the first step, the curing temperature is 220-270 ℃, and the curing time is 2-4 h.
In the actual operation process, after solidification is completed, the substrate is subjected to alcohol solution ultrasonic cleaning, then is cleaned by clear water, and is dried for later use after cleaning.
Preferably, in the second step, the addition amount of the DVB is 30-50 wt% of the mass of the polymethylsilane.
In the invention, DVB is added as a cross-linking agent on one hand, which increases the cross-linking of polymethyl silane, improves the ceramic yield, reduces the overflow of cracked gas in the later high-temperature treatment process, and reduces the generation of coating pores and cracks; on the other hand, the addition of DVB is also a diluent, so that the viscosity of the coating is adjusted, and the coating is convenient to brush. The DVB content is too small, the cross-linking of the polymethylsilane is insufficient, the ceramic yield is low, small pores are easily generated in the fired coating, and meanwhile, the DVB content is too small, the coating is viscous, the powder is not uniformly dispersed and cannot be spread during coating, and the surface of the fired coating is not smooth. When the amount of DVB is excessive, DVB which is not crosslinked with polymethyl silane can generate free carbon by self-crosslinking, and the amount of DVB is excessive, the coating is thinner, the sintered coating is thinner, and the ablation resistance is poor.
Preferably, in the second step, the addition amount of the metal powder is 30-50 wt% of the mass of the polymethylsilane,
preferably, in the second step, the metal powder is at least one selected from Zr, Ti, Al, Fe, and Cu.
Preferably, in the second step, the particle size of the metal powder is less than or equal to 5 μm, and preferably 1-3 μm.
In the invention, the metal powder is active powder which can not only react with the polymethylsilane but also promote the crosslinking of the polymethylsilane and DVB, and simultaneously can react with the cracking atmosphere of the polymethylsilane in the sintering process to generate zirconium carbide or titanium carbide ceramic, so that the high temperature resistance and compactness of the coating are improved.
In the actual operation process, firstly, DVB is added into the polymethyl silane, then the metal powder is added, and the mixture is stirred for 1 to 2 hours until the mixture is uniformly mixed, so that a mixture is obtained.
In a preferable scheme, in the second step, the adding amount of the ceramic powder is 80-100 wt% of the mass of the polymethylsilane.
Preferably, in the second step, the ceramic powder is selected from at least one of ZrC, ZrN and SiC.
Further preferably, in the step (a), the ceramic powder is a mixed powder of ZrC, ZrN and SiC, wherein the mixed powder comprises, by mass: ZrC: ZrN is 7-15: 1-2: 1-2.
The inventor finds that the ceramic powder formula in the further optimization has the best combination property of the coating and the best oxidation resistance, and the inventor deduces that the ceramic powder in the formula is probably just cracked with the polymethyl silicane and forms a grading distribution with the ceramic powder generated by the reaction of the titanium powder and the zirconium powder.
Preferably, in the second step, the particle size of the ceramic powder is less than or equal to 5 μm, and preferably 1-3 μm. Controlling the particle size of the ceramic powder within the above range can ensure uniformity of the coating and controllable thickness, and if too large, can cause cracking of the coating.
In the actual operation process, the ceramic powder is added into the mixture and stirred for 1-2 hours to obtain the coating slurry.
According to the preferable scheme, in the third step, the drying process is that the substrate is dried in the air for 1-3 hours, then the substrate is placed in an oven, the temperature is raised to 100-150 ℃ at the temperature raising speed of 1-2 ℃/min, and the temperature is kept for 2-3 hours.
When drying, the heating rate is controlled in the preferable range, the coating can be ensured to be dried inside and outside simultaneously, if the heating rate is too high during drying, the surface of the coating is easy to dry to form a solidified film of polymethyl silane, the coating is not dried completely, the evaporated liquid can penetrate through the solidified film on the surface of the coating during drying, and the coating is easy to generate air holes or crack after high-temperature treatment. The drying speed is too slow, and the drying time is prolonged.
Preferably, in step three, the sintering procedure is as follows: heating to 250-300 ℃ at a speed of 1-2 ℃/min, preserving heat for 90-120 min, heating to 450-550 ℃ at a speed of 3-5 ℃/min, preserving heat for 100-120 min, heating to 600-700 ℃ at a speed of 3-5 ℃/min, preserving heat for 60-90 min, heating to 800-1000 ℃ at a speed of 5-10 ℃/min, and preserving heat for 90-120 min.
In the actual operation process, the sintering is carried out under the protection of a nitrogen atmosphere. The inventors have found that sintering under the preferred sintering procedure described above ensures maximum ceramic yield of the polymethylsilane and that the coating does not crack but only shrinks.
The principle and the advantages are as follows:
according to the preparation method of the SiC coating provided by the invention, the polymethyl silane is used as a coating main body material, the active metal powder and the inert ceramic powder are added, the prepared coating slurry can be used for preparing the SiC high-temperature resistant coating on a high-density blank by adopting a brushing method, and the coating has the characteristics of compactness, high bonding strength, high temperature resistance and oxidation resistance.
In order to solve the problem of bonding strength between the SiC coating prepared by the coating method and the high-density green body, the green body is subjected to vacuum impregnation by the polymethylsilane, and after the impregnation is finished, the surface of the green body is cured at 270 ℃ through 220-plus-one treatment to form a polymethylsilane film coating, so that an interface condition is provided for the subsequent bonding of the coating slurry and the green body. And secondly, sintering the polymethyl silane to form the high-temperature-resistant and antioxidant SiC. And in the aspect of coating slurry preparation, the coating has more excellent high-temperature-resistant oxidation resistance by adding high-temperature-resistant powder such as ZrC, ZrN, Ti powder, Zr powder and the like, and in the aspect of coating densification, the coating can not shrink and generate microcracks in the whole sintering process by adjusting the proportion of the polymethylsilane, the active filler, the inert filler and the solvent, so that the dense oxidation-resistant coating is obtained.
Polymethyl silicane as an organic ceramic precursor is in a liquid state at normal temperature, and is subjected to high-temperature sintering treatment to convert organic matters into inorganic ceramic materials, so that SiC with the carbon-silicon ratio close to 1:1 is formed. Meanwhile, the coating slurry has proper viscosity and activity, and can obtain coating slurry with cohesiveness and different properties by adding metal active filler and inert filler.
The SiC high-temperature resistant coating prepared by the method has compact coating, high bonding strength with a high-density blank, difficult shedding and cracking of the coating and good oxidation resistance below 1600 ℃.
The method has the advantages of low requirement on equipment, short manufacturing period, high efficiency and safe and controllable preparation process. Meanwhile, the prepared SiC coating has high bonding strength with a high-density blank, is compact, is not easy to fall off, has oxidation resistance, and can meet the requirement of high-temperature resistance and oxidation resistance at 1600 ℃.
Detailed Description
The present invention will be described in further detail with reference to examples.
Example 1
In this embodiment, the method for preparing the SiC high-temperature resistant coating by the brushing method includes the following steps:
1. high density green body precoat
1.1, filling the high-density blank including the graphite piece and the carbon piece into a closed container, vacuumizing the container until the vacuum degree is 9Pa, and continuing vacuumizing for 1 hour. Then sucking the polymethylsilane in vacuum until the green body is submerged by the polymethylsilane, and then soaking for 30min under the vacuum condition.
1.2 transferring the blank into an infrared oven for curing treatment after the impregnation is finished. The curing conditions were set as follows: heating to 250 deg.C at 1 deg.C/min, and maintaining for 3 hr.
1.3 soaking the cured blank body in absolute ethyl alcohol, putting the blank body into an ultrasonic pool, and carrying out ultrasonic treatment for 30min under the ultrasonic frequency of 46 HZ;
1.4 cleaning the blank body with clean water for 3 times;
1.5 after cleaning, putting the mixture into an infrared oven to be dried for 2 hours at the temperature of 100 ℃;
2. coating slurry preparation
2.1 the Polymethylsilane (PMS) used for preparing the coating slurry is produced and provided by Bowang carbon pottery Co., Ltd, Hunan, the molecular weight is 800-1000, the viscosity is 200-300 cP, and the ceramic yield is about 60%. Adding a DVB solvent into the polymethyl silane, wherein the DVB is produced by Shanghai Pont chemical industry Co., Ltd, and the addition amount of the DVB solvent accounts for 50 wt% of PMS;
2.2, continuously adding Ti and Zr metal powder, wherein the metal powder is purchased from China institute of metallurgy powder, the powder size is 1-3um, the purity of the Zr powder is more than or equal to 99.4 percent, the purity of the Ti powder is more than or equal to 99.9 percent, the total content of Ti and Zr is 50wt percent of PMS, and the ratio of Ti powder to Zr powder is as follows: the mass ratio of Zr powder is 1: 1.
2.3, mechanically stirring for 2 hours to uniformly mix;
2.4 adding 2000 meshes of SiC, ZrC and ZrN, wherein ZrC is purchased from China institute of metallurgy powder, the powder size is 1-3um, the purity is more than or equal to 99.5%, ZrN is purchased from Hebei kenna metal, the powder size is 2um, the purity is more than or equal to 99.9%, 2000 meshes of SiC is purchased from Shanghai Shazhong nanometer technology Limited company, the powder size is 2000 meshes, and the purity is more than or equal to 99.9%. The total amount of the powder accounts for 100 wt% of PMS; 2000 mesh SiC: ZrC: ZrN mass ratio 8:1: 1. 2.5, mechanically stirring for 2 hours to uniformly mix;
3. coating method for preparing coating
3.1 dipping the slurry by a fine and soft brush to brush a coating on the blank, wherein the brushing mode adopts a cross method to ensure the uniformity of the coating and the thickness of the coating.
3.2 the prepared coating green body is firstly dried in the air for 3h, and then is put into an infrared oven for drying treatment, the temperature of the oven is set to be 100 ℃, the heating speed is set to be 1 ℃/Min, and the coating green body is dried for 2h under the condition of 100 ℃.
3.3 placing the dried green body into a tube furnace for high-temperature sintering, wherein the whole sintering system adopts N2As a protective atmosphere environment, the setting procedure is as follows: room temperature-260 deg.C, 180 min; keeping the temperature at 260 ℃ for 100 min; 260-500 ℃ for 80 min; keeping the temperature at 500 ℃ for 120 min; 500-600 ℃ for 30 min; keeping the temperature at 600 ℃ for 60 min; 600-800 ℃ for 40 min; keeping the temperature at 800 ℃ for 120 min. And sintering to obtain the high-temperature resistant coating.
Coating performance:
the coating is completely coated and has no pulverization after being burnt in air at 1300 ℃ for 10 hours, and the weight loss rate is 0.6 percent.
Example 2
In this embodiment, the method for preparing the SiC high-temperature resistant coating by the brushing method includes the following steps:
1. high density green body precoat
1.1, filling the high-density blank including the graphite piece and the carbon piece into a closed container, vacuumizing the container until the vacuum degree is 15Pa, and continuously vacuumizing for 1 hour. The polymethylsilane is drawn in by vacuum until the polymethylsilane floods the green body. The impregnation was carried out under vacuum for 1 h.
And 1.2, transferring the blank into an infrared oven for curing after the impregnation is finished. The curing conditions were set as follows: the temperature is raised to 270 ℃ at the speed of 1 ℃/min, and the temperature is kept for 2 hours.
1.3 soaking the cured blank body in absolute ethyl alcohol, putting the blank body into an ultrasonic pool, and carrying out ultrasonic treatment for 30min under the ultrasonic frequency of 46 HZ;
1.4 cleaning the blank body with clean water for 3 times;
1.5 after cleaning, putting the mixture into an infrared oven to be dried for 2 hours at the temperature of 100 ℃;
2. coating slurry preparation
2.1 the Polymethylsilane (PMS) used for preparing the coating slurry is produced and provided by Bowang carbon pottery Co., Ltd, Hunan, the molecular weight is 800-1000, the viscosity is 200-300 cP, and the ceramic yield is about 60%. Adding a DVB solvent into the polymethyl silane, wherein the DVB is produced by Shanghai Pont chemical industry Co., Ltd, and the addition amount of the DVB solvent accounts for 30 wt% of PMS;
2.2, continuously adding Ti and Zr metal powder, wherein the metal powder is purchased from China institute of metallurgy powder, the powder size is 1-3um, the purity of the Zr powder is more than or equal to 99.4 percent, the purity of the Ti powder is more than or equal to 99.9 percent, the total content of Ti and Zr is 50wt percent of PMS, and the ratio of Ti powder to Zr powder is as follows: the mass ratio of Zr powder is 1: 1.
2.3, mechanically stirring for 2 hours to uniformly mix;
2.4 adding 2000 meshes of SiC, ZrC and ZrN, wherein ZrC is purchased from China institute of metallurgy powder, the powder size is 1-3um, the purity is more than or equal to 99.5%, ZrN is purchased from Hebei kenna metal, the powder size is 2um, the purity is more than or equal to 99.9%, 2000 meshes of SiC is purchased from Shanghai Shazhong nanometer technology Limited company, the powder size is 2000 meshes, and the purity is more than or equal to 99.9%. The total amount of the powder accounts for 100 wt% of PMS; 2000 mesh SiC: ZrC: the mass ratio of ZrN is 7:1: 1.
2.5, mechanically stirring for 2 hours to uniformly mix;
3. coating method for preparing coating
3.1 dipping the slurry by a fine and soft brush to brush the coating on the blank, wherein the brushing mode adopts a cross method to ensure the uniformity of the coating and the thickness of the coating.
3.2 air-drying the prepared coating blank for 1h, then placing the coating blank into an infrared oven for drying treatment, setting the temperature of the oven to be 150 ℃, setting the heating speed to be 1 ℃/Min, and preserving heat and drying for 2h at the temperature of 150 ℃.
3.3 placing the dried green body into a tube furnace for high-temperature sintering, wherein the whole sintering system adopts N2As a protective atmosphere environment, the setting procedure is as follows: room temperature-300 deg.C, 200 min; keeping the temperature at 300 ℃ for 100 min; 300-550 ℃ for 80 min; preserving heat for 120min at 550 ℃; at 550-700 ℃ for 30 min; keeping the temperature at 700 ℃ for 60 min; 700-800 ℃ for 30 min; keeping the temperature at 800 ℃ for 120 min. And sintering to obtain the high-temperature resistant coating.
Coating performance:
the coating is completely coated and has no pulverization after being burnt in air at 1300 ℃ for 10 hours, and the weight loss rate is 0.9 percent.
Example 3
In this embodiment, the method for preparing the SiC high-temperature resistant coating by the brushing method includes the following steps:
1. high density green body precoat
1.1, filling the high-density blank including the graphite piece and the carbon piece into a closed container, vacuumizing the container until the vacuum degree is 20Pa, and continuously vacuumizing for 1 hour. The polymethylsilane is drawn in by vacuum until the polymethylsilane floods the green body. The impregnation was carried out under vacuum for 2 h.
And 1.2, transferring the blank into an infrared oven for curing after the impregnation is finished. The curing conditions were set as follows: heating to 220 deg.C at 1 deg.C/min, and holding for 4 hr.
1.3 soaking the cured blank body in absolute ethyl alcohol, putting the blank body into an ultrasonic pool, and carrying out ultrasonic treatment for 30min under the ultrasonic frequency of 46 HZ;
1.4 cleaning the blank body with clean water for 3 times;
1.5 after cleaning, putting the mixture into an infrared oven to be dried for 2 hours at the temperature of 100 ℃;
2. coating slurry preparation
2.1 the Polymethylsilane (PMS) used for preparing the coating slurry is produced and provided by Bowang carbon pottery Co., Ltd, Hunan, the molecular weight is 800-1000, the viscosity is 200-300 cP, and the ceramic yield is about 60%. Adding a DVB solvent into the polymethyl silane, wherein the DVB is produced by Shanghai Pont chemical industry Co., Ltd, and the addition amount of the DVB solvent accounts for 40 wt% of PMS;
2.2, continuously adding Ti and Zr metal powder, wherein the metal powder is purchased from China institute of metallurgy powder, the powder size is 1-3um, the purity of the Zr powder is more than or equal to 99.4 percent, the purity of the Ti powder is more than or equal to 99.9 percent, the total content of Ti and Zr is 50wt percent of PMS, and the ratio of Ti powder to Zr powder is as follows: the mass ratio of Zr powder is 1: 1.
2.3, mechanically stirring for 2 hours to uniformly mix;
2.4 adding 2000 meshes of SiC, ZrC and ZrN, wherein ZrC is purchased from China institute of metallurgy powder, the powder size is 1-3um, the purity is more than or equal to 99.5%, ZrN is purchased from Hebei kenna metal, the powder size is 2um, the purity is more than or equal to 99.9%, 2000 meshes of SiC is purchased from Shanghai Shazhong nanometer technology Limited company, the powder size is 2000 meshes, and the purity is more than or equal to 99.9%. The total amount of the powder accounts for 100 wt% of PMS; 2000 mesh SiC: ZrC: the ZrN mass ratio is 15:2: 2.
2.5, mechanically stirring for 2 hours to uniformly mix;
3. coating method for preparing coating
3.1 dipping the slurry by a fine and soft brush to brush a coating on the blank, wherein the brushing mode adopts a cross method to ensure the uniformity of the coating and the thickness of the coating.
3.2 the prepared coating green body is firstly dried in the air for 2h, and then is put into an infrared oven for drying treatment, the temperature of the oven is set to be 120 ℃, the heating speed is set to be 1 ℃/Min, and the coating green body is dried for 2.5h under the condition of 120 ℃.
3.3 placing the dried green body into a tube furnace for high-temperature sintering, wherein the whole sintering system adopts N2As a protective atmosphere environment, the setting procedure is as follows: room temperature-250 deg.C, 120 min; keeping the temperature at 250 ℃ for 120 min; at 250-450 deg.c for 60 min; keeping the temperature at 450 ℃ for 120 min; 40min at 450-600 ℃; keeping the temperature at 600 ℃ for 60 min; 600-800 ℃ for 20 min; keeping the temperature at 800 ℃ for 90 min. And sintering to obtain the high-temperature resistant coating.
Coating performance:
the coating is completely coated and has no pulverization after being burnt in air at 1300 ℃ for 10 hours, and the weight loss rate is 1.1 percent.
Comparative example 1
The other conditions were the same as in example 1 except that the precoating treatment was not performed. The sintered coating and the base have poor adhesion, the surface of the base is uneven, the coating is pulverized completely after being burnt in air at 1300 ℃ for 10 hours, the structure of the base is damaged, and the weight loss rate is 32.7%.
Comparative example 2
The other conditions were the same as in example 1 except that the sintering procedure was: raising the temperature to 800 ℃ at the speed of 5 ℃/min, and preserving the temperature for 120 min. The surface of the sintered coating has a chalking phenomenon, and a plurality of small air holes are generated on the surface of the coating.
Comparative example 3
The other conditions were the same as in example 1 except that about 50 μm was selected as the metal powder and the ceramic powder added to the coating slurry. The sintered coating has an uneven and thick surface and a small amount of cracks. The coating is pulverized after being burnt in air at 1300 ℃ for 10 hours, part of the coating falls off, and the weight loss rate is 8.4%.
Comparative example 4
The other conditions are the same as example 1, except that the metal powder and the ceramic powder are added simultaneously when the coating slurry is prepared, and the mixture is mechanically stirred for 4 hours and uniformly mixed. The sintered coating has uneven surface and pores. Burning in air at 1300 deg.C for 10 hr to make the coating powder, part of the coating fall off, and the weight loss rate is 5.7%
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all modifications, alterations and equivalents of the above embodiments according to the technical spirit of the present invention are still within the scope of the present invention.
Claims (6)
1. A preparation method of a SiC coating is characterized by comprising the following steps: the method comprises the following steps:
step one, pre-coating treatment
Vacuum dipping, curing and drying a substrate by adopting a dipping agent to obtain a precoated substrate, wherein the dipping agent contains polymethyl silane;
step two, preparation of coating slurry
Mixing polymethyl silane, divinyl benzene and metal powder to obtain a mixture, adding ceramic powder into the mixture, and mixing to obtain coating slurry;
the adding amount of the metal powder is 30-50 wt% of the mass of the polymethylsilane,
the metal powder is selected from at least one of Zr, Ti, Al, Fe and Cu;
the particle size of the metal powder is less than or equal to 5 mu m;
the addition amount of the ceramic powder is 80-100 wt% of the mass of the polymethylsilane,
the ceramic powder is selected from at least one of ZrC, ZrN and SiC,
step three, preparation of coating
Coating the surface of the substrate subjected to the pre-coating treatment obtained in the step one with the coating slurry obtained in the step two, drying and sintering to obtain the coating;
the sintering procedure is as follows: heating to 250-300 ℃ at a speed of 1-2 ℃/min, preserving heat for 90-120 min, heating to 450-550 ℃ at a speed of 3-5 ℃/min, preserving heat for 100-120 min, heating to 600-700 ℃ at a speed of 3-5 ℃/min, preserving heat for 60-90 min, heating to 800-1000 ℃ at a speed of 5-10 ℃/min, and preserving heat for 90-120 min.
2. The method of claim 1 for preparing a SiC coating, wherein: in the first step, the vacuum impregnation time is 30-120 min, and the vacuum degree is controlled to be below 20 Pa.
3. The method of claim 1 for preparing a SiC coating, wherein: in the first step, the curing temperature is 220-.
4. The method of claim 1 for preparing a SiC coating, wherein: in the second step, the addition amount of the DVB is 30-50 wt% of the mass of the polymethylsilane.
5. The method of claim 1 for preparing a SiC coating, wherein: in the second step, the ceramic powder is mixed powder of ZrC, ZrN and SiC, wherein the mixed powder comprises the following components in percentage by mass: ZrC: ZrN is 7-15: 1-2: 1-2;
in the second step, the grain diameter of the ceramic powder is less than or equal to 5 mu m.
6. The method of claim 1 for preparing a SiC coating, wherein: in the third step, the drying process is to air-dry the substrate in the air for 1-3 hours, then place the substrate in an oven, heat the substrate to 100-150 ℃ at a heating rate of 1-2 ℃/min, and keep the temperature for 2-3 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011453458.4A CN112537962B (en) | 2020-12-11 | 2020-12-11 | Preparation method of SiC coating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011453458.4A CN112537962B (en) | 2020-12-11 | 2020-12-11 | Preparation method of SiC coating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN112537962A CN112537962A (en) | 2021-03-23 |
| CN112537962B true CN112537962B (en) | 2022-05-27 |
Family
ID=75018417
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011453458.4A Active CN112537962B (en) | 2020-12-11 | 2020-12-11 | Preparation method of SiC coating |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112537962B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115894085B (en) * | 2022-11-15 | 2023-08-11 | 湖南博望碳陶有限公司 | Composite ceramic coating material and preparation method and application thereof |
| CN115677380B (en) * | 2022-11-15 | 2023-05-12 | 湖南博望碳陶有限公司 | Preparation method of thermal field thermal insulation piece composite ceramic coating |
| CN115611646B (en) * | 2022-11-15 | 2023-04-25 | 湖南博望碳陶有限公司 | Preparation method of ablation-resistant composite ceramic coating, ablation-resistant composite ceramic coating and application |
| CN116768652A (en) * | 2023-06-20 | 2023-09-19 | 湖南博望碳陶有限公司 | Preparation method of high-temperature-resistant ceramic and high-temperature-resistant ceramic |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101306959B (en) * | 2008-07-07 | 2011-05-18 | 中国人民解放军国防科学技术大学 | Method for preparing superhigh temperature resistant ceramic coat |
| CN105481477B (en) * | 2015-12-29 | 2018-01-02 | 湖南博望碳陶有限公司 | A kind of preparation method of graphite/SiC ceramic matrix composite material |
-
2020
- 2020-12-11 CN CN202011453458.4A patent/CN112537962B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN112537962A (en) | 2021-03-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN112537962B (en) | Preparation method of SiC coating | |
| CN109293383B (en) | Fiber-reinforced carbon-silicon carbide ceramic matrix composite and preparation method thereof | |
| CN107814591B (en) | Preparation method of boride modified silicon-based antioxidant coating on surface of carbon material | |
| CN109824374B (en) | Method for preparing high-performance silicon carbide coating on surface of carbon-carbon composite heat-insulating material | |
| CN112759423B (en) | Coating carbon-carbon composite material crucible and preparation method thereof | |
| CN109437943B (en) | Cf/C-SiC-ZrB2Composite material and preparation method thereof | |
| CN110357632B (en) | ZrC/SiC complex phase ceramic precursor and preparation method thereof | |
| CN109467457B (en) | Composition, high-emissivity antioxidant coating prepared from composition and used for porous carbon fiber heat-insulating material surface and preparation method of high-emissivity antioxidant coating | |
| CN113735629B (en) | Carbon material wide-temperature-range anti-oxidation and anti-scouring complex-phase ceramic coating and preparation method thereof | |
| CN114591102A (en) | C/C composite material SiB6-Glass oxidation resistant coating and preparation method thereof | |
| CN110950681B (en) | Preparation method of graphite oxidation-resistant coating | |
| CN115894085B (en) | Composite ceramic coating material and preparation method and application thereof | |
| CN110158309B (en) | Method for preparing carbon fiber with silicon carbide coating on surface | |
| CN110872198B (en) | Nanowire toughened ZrB2Preparation method of-ZrC-SiC oxidation resistant coating | |
| CN213446876U (en) | Carbon fiber plate with silicon carbide coating on surface | |
| CN113106416A (en) | Ablation-resistant ZrC/SiC multilayer alternating coating and preparation method thereof | |
| CN115611646B (en) | Preparation method of ablation-resistant composite ceramic coating, ablation-resistant composite ceramic coating and application | |
| CN114315390B (en) | Carbon/carbon composite material surface wide-temperature-range long-life antioxidation coating and low-temperature preparation method | |
| CN110357666B (en) | Ceramic composite coating and preparation method thereof | |
| JPH05319928A (en) | Production of highly functional carbon/ceramic composite material | |
| CN113307659B (en) | Preparation method for forming high-emissivity coating on heat insulation tile | |
| CN112174698B (en) | Carbon material surface antioxidant protective coating and preparation method thereof | |
| CN115819119B (en) | Coating forming method of isostatic pressing graphite crucible | |
| CN108585954B (en) | Radial nanowire growing on surface of C/C-Si composite material and preparation method at normal temperature | |
| CN115650754B (en) | SiC coating with dispersed particles on surface of carbon material for strengthening and toughening and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |