CN110078519B - Preparation method of porous silicon nitride ceramic - Google Patents
Preparation method of porous silicon nitride ceramic Download PDFInfo
- Publication number
- CN110078519B CN110078519B CN201910382733.9A CN201910382733A CN110078519B CN 110078519 B CN110078519 B CN 110078519B CN 201910382733 A CN201910382733 A CN 201910382733A CN 110078519 B CN110078519 B CN 110078519B
- Authority
- CN
- China
- Prior art keywords
- heating
- silicon nitride
- porous silicon
- green body
- deionized water
- 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
- HQVNEWCFYHHQES-UHFFFAOYSA-N silicon nitride Chemical compound N12[Si]34N5[Si]62N3[Si]51N64 HQVNEWCFYHHQES-UHFFFAOYSA-N 0.000 title claims abstract description 37
- 239000000919 ceramic Substances 0.000 title claims abstract description 35
- 229910021426 porous silicon Inorganic materials 0.000 title claims abstract description 33
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 72
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 52
- 229920000877 Melamine resin Polymers 0.000 claims abstract description 30
- JDSHMPZPIAZGSV-UHFFFAOYSA-N melamine Chemical compound NC1=NC(N)=NC(N)=N1 JDSHMPZPIAZGSV-UHFFFAOYSA-N 0.000 claims abstract description 30
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims abstract description 25
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 claims abstract description 22
- 238000000034 method Methods 0.000 claims abstract description 20
- 239000008367 deionised water Substances 0.000 claims abstract description 19
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 19
- 239000012300 argon atmosphere Substances 0.000 claims abstract description 18
- 239000013078 crystal Substances 0.000 claims abstract description 13
- 238000004108 freeze drying Methods 0.000 claims abstract description 10
- 239000002253 acid Substances 0.000 claims abstract description 8
- 239000012299 nitrogen atmosphere Substances 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims description 92
- 238000002156 mixing Methods 0.000 claims description 44
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 28
- 238000003756 stirring Methods 0.000 claims description 28
- 239000007788 liquid Substances 0.000 claims description 27
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 26
- 229910002804 graphite Inorganic materials 0.000 claims description 25
- 239000010439 graphite Substances 0.000 claims description 25
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 15
- 229910017604 nitric acid Inorganic materials 0.000 claims description 15
- 229910052757 nitrogen Inorganic materials 0.000 claims description 14
- 238000001291 vacuum drying Methods 0.000 claims description 14
- 238000007710 freezing Methods 0.000 claims description 13
- 230000008014 freezing Effects 0.000 claims description 13
- 238000007731 hot pressing Methods 0.000 claims description 13
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 12
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 8
- 239000011148 porous material Substances 0.000 abstract description 8
- 238000005245 sintering Methods 0.000 abstract description 8
- 238000010521 absorption reaction Methods 0.000 abstract description 6
- 239000000654 additive Substances 0.000 abstract description 3
- 230000000996 additive effect Effects 0.000 abstract description 3
- 238000011161 development Methods 0.000 abstract description 3
- 239000000428 dust Substances 0.000 abstract description 3
- 238000001914 filtration Methods 0.000 abstract description 3
- 238000000746 purification Methods 0.000 abstract description 3
- 239000002912 waste gas Substances 0.000 abstract description 3
- 239000000243 solution Substances 0.000 description 58
- 239000000203 mixture Substances 0.000 description 41
- 239000000084 colloidal system Substances 0.000 description 20
- 239000000463 material Substances 0.000 description 16
- 239000000499 gel Substances 0.000 description 11
- 239000007864 aqueous solution Substances 0.000 description 5
- 229910052581 Si3N4 Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 235000019441 ethanol Nutrition 0.000 description 3
- 239000012071 phase Substances 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- 235000012239 silicon dioxide Nutrition 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 240000000828 Tecoma stans Species 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000007171 acid catalysis Methods 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 238000005336 cracking Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000000413 hydrolysate Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 238000000197 pyrolysis Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- -1 tetraethoxysilane alkoxide Chemical class 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
Images
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
- C04B35/58—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 borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides
- C04B35/584—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 borides, nitrides, i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides or silicides based on silicon 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
- 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
-
- 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
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/06—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances
- C04B38/0605—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by burning-out added substances by burning natural expanding materials or by sublimating or melting out added substances by sublimating
-
- 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
- C04B2235/46—Gases other than oxygen used as reactant, e.g. nitrogen used to make a nitride phase
-
- 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
- C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
- C04B2235/483—Si-containing organic compounds, e.g. silicone resins, (poly)silanes, (poly)siloxanes or (poly)silazanes
-
- 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
-
- 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
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/74—Physical characteristics
- C04B2235/77—Density
-
- 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
- C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
- C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Ceramic Products (AREA)
Abstract
The invention discloses a preparation method of porous silicon nitride ceramic, which comprises the steps of taking melamine as an additive, preparing melamine, methanol, tetraethoxysilane, absolute ethyl alcohol, acid and deionized water into gel, adopting a freeze drying process, placing the gel at-60-0 ℃ for freeze drying to obtain a green body, and sintering the green body for the first time in an argon atmosphere and for the second time in a nitrogen atmosphere to obtain the structural porous silicon nitride ceramic with a main crystal position as a channel and a dendritic crystal position as a cavity Helmholtz array. The preparation method has the characteristics of simple preparation process, controllable pore structure, high porosity of the prepared sample, excellent strength and the like; the method can be applied to various fields of dust removal and purification, waste gas filtration, noise and sound absorption and the like, and provides technical support for the sustainable development of economy in China and regions.
Description
Technical Field
The invention belongs to the technical field of preparation of porous silicon nitride ceramics, and particularly relates to a preparation method of porous silicon nitride ceramics.
Background
Porous silicon nitride (Si)3N4) The special fibrous grain interlocking structure enables the high-porosity acoustic liner material to have excellent specific strength and fracture toughness, and the high-porosity acoustic liner material is a high-temperature acoustic liner material with wide application prospect. The sound absorption performance of the material is related to parameters such as porosity, pore diameter, cavity structure and the like of the porous ceramic, and the parameters determine the constitutive relation between the sound absorption performance and the microstructure of the porous silicon nitride material. After the melamine is pyrolyzed, a large amount of gas and instantaneous high internal pressure are generated, the formation of a porous structure is promoted, and a horn shape is formedThe porous structure of (3). Meanwhile, carbide nitrogen formed after cracking is used as a carbon source and also plays a role of a framework. And combining a freeze drying process, controlling a freezing process temperature field and a liquid phase medium solidification behavior to form a dendritic crystal structure, and constructing a novel three-dimensional network structure by taking a main crystal position as a channel and taking a dendritic crystal position as a cavity Helmholtz array after vacuum drying and sintering, so that the low-frequency sound absorption performance of the material is improved. The existing research does not disclose a method for preparing porous silicon nitride ceramics by using melamine as a pore-forming agent and combining a freeze drying process.
Disclosure of Invention
The technical problem to be solved by the present invention is to provide a method for preparing porous silicon nitride ceramics, which has the advantages of simple preparation process, controllable pore structure and high porosity of prepared samples, and overcomes the defects in the prior art.
The invention adopts the following technical scheme:
a preparation method of porous silicon nitride ceramic comprises the steps of taking melamine as an additive, respectively adding deionized water into the melamine, methanol, ethyl orthosilicate and absolute ethyl alcohol, mixing to prepare gel, adopting a freeze drying process, placing the gel at-60-0 ℃ for freeze drying to obtain a green body, and performing primary sintering in an argon atmosphere and secondary sintering in a nitrogen atmosphere to obtain the porous silicon nitride ceramic with the structure that a main crystal position is a channel and a dendritic crystal position is a cavity Helmholtz array.
Specifically, dissolving melamine in methanol and a first part of deionized water, and heating in a water bath to obtain a white transparent liquid; dissolving ethyl orthosilicate in absolute ethyl alcohol and a second part of deionized water, stirring and heating to obtain a transparent solution, mixing the white transparent solution and the transparent solution, heating to 55-75 ℃, then adding acid, continuously stirring, and adjusting the pH value to form gel.
Further, melamine: methanol: the mole ratio of the first portion of deionized water is 1: (8-10): (40-50), heating to 60-75 ℃ in a water bath, and continuously reacting for 15-25 min to obtain white transparent liquid.
Further, ethyl orthosilicate: anhydrous ethanol: the molar ratio of the second part of deionized water is 1: (1-1.5): (1.5-2), heating to 55-75 ℃ under continuous stirring, and continuously reacting for 20-30 min to obtain a transparent solution.
Further, (melamine + methanol + first portion of deionized water): the volume ratio of the ethyl orthosilicate, the absolute ethyl alcohol and the second part of deionized water is (1-1.5): 1.
further, the pH value is 1.5-4.5.
Further, the acid is nitric acid, hydrochloric acid or acetic acid.
Specifically, the gel is frozen for 2-6 hours, and then vacuum drying is carried out for 8-48 hours to obtain a green body.
Specifically, the green body is uniformly placed in a graphite crucible coated with BN, and is placed in a vacuum hot-pressing furnace, the temperature is gradually increased to 700-900 ℃ at the temperature increasing speed of 0.5-1 ℃/min under the argon atmosphere, the temperature is kept for 30-60 min, and then the temperature is gradually increased to 1400-1800 ℃ at the temperature increasing speed of 5-15 ℃/min under the nitrogen pressure of 0.2-0.6 MPa, and the temperature is kept for 1-2 h.
Compared with the prior art, the invention has at least the following beneficial effects:
according to the preparation method of the porous silicon nitride ceramic, important structural parameters such as porosity, pore diameter and cavity structure are controlled by selecting raw materials and the preparation method. The preparation method has the characteristics of simple preparation process, controllable pore structure, high porosity of the prepared sample, excellent strength and the like; the method can be applied to various fields of dust removal and purification, waste gas filtration, noise and sound absorption and the like, and provides technical support for the sustainable development of economy in China and regions.
Further, the melamine is dissolved in methanol and aqueous solution to prepare white transparent solution of the alcohol-based melamine.
Further, the tetraethoxysilane alkoxide is hydrolyzed to form a hydroxylated product.
Further, acid is added as a catalyst, the pH value is adjusted, condensation reaction occurs between silicic acid or between silicic acid and ethyl orthosilicate in an acid catalysis system, and gel is formed with alcohol-based melamine.
Furthermore, in order to ensure that the silicon nitride can be generated by the proportional reaction in the later period, the corresponding volume ratio is set.
Further, nitric acid, hydrochloric acid or acetic acid is adopted to adjust the pH value of the hydrolysate.
Furthermore, the physical process of preparing the green body by adopting a freeze drying method is simple, flexible and environment-friendly.
Further, one-time argon atmosphere sintering is carried out to fully ensure the pyrolysis of the gel; the secondary nitrogen atmosphere sintering is beneficial to the formation of the silicon nitride ceramics.
In conclusion, the preparation method disclosed by the invention has the characteristics of simple preparation process, controllable pore structure, high porosity of the prepared sample, excellent strength and the like; the method can be applied to various fields of dust removal and purification, waste gas filtration, noise and sound absorption and the like, and provides technical support for the sustainable development of economy in China and regions.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is an XRD pattern of porous silicon nitride ceramics in examples 2, 4 and 6 of the present invention;
FIG. 2 is an SEM photograph of the porous silicon nitride ceramic of example 10.
Detailed Description
The invention provides a preparation method of porous silicon nitride ceramic, which comprises the steps of taking melamine as an additive, preparing melamine, methanol, tetraethoxysilane, ethanol, nitric acid and deionized water into gel, adopting a freeze drying process, placing the gel at-60-0 ℃ for freeze drying to obtain a green body, and sintering the green body for the first time in an argon atmosphere and for the second time in a nitrogen atmosphere to obtain the porous silicon nitride ceramic with a structure, wherein a main crystal position is a channel, and a dendritic crystal position is a cavity Helmholtz array.
The invention relates to a preparation method of porous silicon nitride ceramics, which comprises the following steps:
s1, dissolving melamine into methanol and deionized water, wherein the mass ratio of melamine: methanol: the molar ratio of the deionized water is 1: (8-10): (40-50), heating to 60-75 ℃ in a water bath, and continuously reacting for 15-25 min to obtain a white transparent liquid;
s2, dissolving tetraethoxysilane in absolute ethyl alcohol and deionized water, wherein the weight ratio of tetraethoxysilane: anhydrous ethanol: the molar ratio of the deionized water is 1: (1-1.5): (1.5-2), heating to 55-75 ℃ under continuous stirring, and continuously reacting for 20-30 min to obtain a transparent solution;
s3, mixing the white transparent liquid obtained in the step S1 and the transparent solution obtained in the step S2, wherein the white transparent liquid: the volume ratio of the transparent solution (1-1.5): 1, heating to 60-75 ℃, adding acid into the mixed transparent solution, continuously stirring, and adjusting the pH value to 1.5-4.5 to form gel;
preferably, the acid is one of nitric acid, hydrochloric acid or acetic acid.
S4, placing the gel obtained in the step S3 in a cold trap at the temperature of-60-0 ℃, freezing for 2-6 hours, and then carrying out vacuum drying for 8-48 hours to prepare a green body;
s5, uniformly placing the green body prepared in the step S4 in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 700-900 ℃ at a heating rate of 0.5-1 ℃/min under an argon atmosphere, preserving heat for 30 min-1 h, then gradually heating to 1400-1800 ℃ at a heating rate of 5-15 ℃/min under a nitrogen pressure of 0.2-0.6 MPa, and preserving heat for 1-2 h to obtain the porous silicon nitride ceramic.
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
(1) Mixing a mixture of 1: 10: dissolving 45 parts of melamine in methanol and water solution, heating the mixture to 60 ℃ in a water bath, and continuously reacting for 15min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1: dissolving 1.5 of tetraethoxysilane in absolute ethyl alcohol and an aqueous solution, heating to 60 ℃ under continuous stirring, and continuously reacting for 20min to obtain a transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 60 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 3 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of-60 ℃ for freezing for 2h, and then carrying out vacuum drying for 8h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 700 ℃ at a heating rate of 0.5 ℃/min under the argon atmosphere, preserving heat for 30min, then gradually heating to 1400 ℃ at a heating rate of 5 ℃/min under the nitrogen pressure of 0.2MPa, and preserving heat for 1h to prepare the porous silicon nitride ceramic.
Example 2
(1) Mixing a mixture of 1: 10: dissolving 42 parts of melamine in methanol and water solution, heating to 62 ℃ in a water bath, and continuously reacting for 17min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1: dissolving 1.7 of tetraethoxysilane in absolute ethyl alcohol and water solution, heating to 62 ℃ under continuous stirring, and continuously reacting for 21min to obtain transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 62 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 3 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of-60 ℃ for freezing for 2.5h, and then carrying out vacuum drying for 10h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 800 ℃ at a heating rate of 0.6 ℃/min under the argon atmosphere, preserving heat for 30min, then gradually heating to 1400 ℃ at a heating rate of 6 ℃/min under the nitrogen pressure of 0.3MPa, and preserving heat for 1.2h to prepare the porous silicon nitride ceramic.
Example 3
(1) Mixing a mixture of 1: 10: dissolving 44% melamine in methanol and water solution, heating to 64 deg.C in water bath, and reacting for 19min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1: dissolving 1.9 of tetraethoxysilane in absolute ethyl alcohol and an aqueous solution, heating to 64 ℃ under continuous stirring, and continuously reacting for 22min to obtain a transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 64 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 3 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of-60 ℃ for freezing for 3h, and then carrying out vacuum drying for 12h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 900 ℃ at the heating rate of 0.6 ℃/min under the argon atmosphere, preserving heat for 30min, then gradually heating to 1400 ℃ at the heating rate of 7 ℃/min under the nitrogen pressure of 0.4MPa, and preserving heat for 1.4h to prepare the porous silicon nitride ceramic.
Example 4
(1) Mixing a mixture of 1: 10: dissolving 46 parts of melamine in methanol and water solution, heating to 66 ℃ in a water bath, and continuously reacting for 20min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1: 2, dissolving the tetraethoxysilane in absolute ethyl alcohol and an aqueous solution, heating to 66 ℃ under continuous stirring, and continuously reacting for 23min to obtain a transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1.5: 1, mixing the materials together, heating the mixture to 66 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 4.5 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of-40 ℃ for freezing for 3.5h, and then carrying out vacuum drying for 14h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 700 ℃ at a heating rate of 0.7 ℃/min under the argon atmosphere, preserving heat for 60min, then gradually heating to 1500 ℃ at a heating rate of 8 ℃/min under the nitrogen pressure of 0.5MPa, and preserving heat for 1.5h to prepare the porous silicon nitride ceramic.
Example 5
(1) Mixing a mixture of 1: 10: dissolving 48 parts of melamine in methanol and water solution (the ratio of methanol to water is 1: 2), heating in water bath to 68 ℃, and continuously reacting for 21min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1.2: dissolving tetraethoxysilane of 1 in absolute ethyl alcohol and water solution, heating to 68 ℃ under continuous stirring, and continuously reacting for 25min to obtain transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1.5: 1, mixing the materials together, heating the mixture to 68 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 4.5 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of-40 ℃ for freezing for 4h, and then carrying out vacuum drying for 20h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 800 ℃ at a heating rate of 0.8 ℃/min under the argon atmosphere, preserving heat for 60min, then gradually heating to 1500 ℃ at a heating rate of 10 ℃/min under the nitrogen pressure of 0.5MPa, and preserving heat for 1.6h to prepare the porous silicon nitride ceramic.
Example 6
(1) Mixing a mixture of 1: 10: dissolving 50 parts of melamine in methanol and water solution, heating to 70 ℃ in a water bath, and continuously reacting for 22min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1.4: dissolving tetraethoxysilane of 1 in absolute ethyl alcohol and water solution, heating to 70 ℃ under continuous stirring, and continuously reacting for 26min to obtain transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1.5: 1, mixing the materials together, heating the mixture to 70 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 4.5 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of-40 ℃ for freezing for 4.5h, and then carrying out vacuum drying for 26h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 900 ℃ at the heating rate of 0.9 ℃/min under the argon atmosphere, preserving heat for 60min, then gradually heating to 1500 ℃ at the heating rate of 12 ℃/min under the nitrogen pressure of 0.5MPa, and preserving heat for 1.8h to prepare the porous silicon nitride ceramic.
Example 7
(1) Mixing a mixture of 1: 9: dissolving 42 parts of melamine in methanol and water solution, heating to 72 ℃ in a water bath, and continuously reacting for 23min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1.5: dissolving 1.5 of tetraethoxysilane in absolute ethyl alcohol and water solution, heating to 72 ℃ under continuous stirring, and continuously reacting for 26min to obtain transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 72 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to be 2 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at-60 ℃ for freezing for 5h, and then carrying out vacuum drying for 32h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 800 ℃ at the heating rate of 1 ℃/min under the argon atmosphere, preserving heat for 60min, then gradually heating to 1600 ℃ at the heating rate of 14 ℃/min under the nitrogen pressure of 0.6MPa, and preserving heat for 1.9h to prepare the porous silicon nitride ceramic.
Example 8
(1) Mixing a mixture of 1: 9: dissolving 46 parts of melamine in methanol and water solution, heating to 73 ℃ in a water bath, and continuously reacting for 24min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1.5: dissolving 1.7 of tetraethoxysilane in absolute ethyl alcohol and water solution, heating to 73 ℃ under continuous stirring, and continuously reacting for 28min to obtain transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 73 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 2 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at-60 ℃ for freezing for 5.5h, and then carrying out vacuum drying for 40h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 700 ℃ at a heating rate of 0.5 ℃/min under the argon atmosphere, preserving heat for 60min, then gradually heating to 1600 ℃ at a heating rate of 15 ℃/min under the nitrogen pressure of 0.4MPa, and preserving heat for 2h to prepare the porous silicon nitride ceramic.
Example 9
(1) Mixing a mixture of 1: 9: dissolving 48 parts of melamine in methanol and water solution, heating to 74 ℃ in a water bath, and continuously reacting for 24min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1.5: dissolving 1.9 of tetraethoxysilane in absolute ethyl alcohol and water solution, heating to 74 ℃ under continuous stirring, and continuously reacting for 290min to obtain transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 74 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to be 2 to form colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at 0 ℃ for freezing for 6h, and then carrying out vacuum drying for 44h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 600 ℃ at a heating rate of 0.5 ℃/min under the argon atmosphere, preserving heat for 60min, then gradually heating to 1600 ℃ at a heating rate of 5 ℃/min under the nitrogen pressure of 0.2MPa, and preserving heat for 1h to prepare the porous silicon nitride ceramic.
Example 10
(1) Mixing a mixture of 1: 9: dissolving 50 parts of melamine in methanol and water solution (the ratio of methanol to water is 1: 2), heating to 75 ℃ in water bath, and continuously reacting for 25min to obtain white transparent liquid;
(2) mixing a mixture of 1: 1.5: 2, dissolving the tetraethoxysilane in absolute ethyl alcohol and an aqueous solution, heating to 75 ℃ under continuous stirring, and continuously reacting for 30min to obtain a transparent solution;
(3) mixing the white transparent liquid obtained in the step (1) and the transparent solution obtained in the step (2) according to a volume ratio of 1: 1, mixing the materials together, heating the mixture to 75 ℃, adding concentrated nitric acid into the mixed transparent solution, continuously stirring the mixture, and adjusting the pH value to 1.5 to form a colloid;
(4) putting the colloid obtained in the step (3) into a cold trap at the temperature of minus 20 ℃ for freezing for 6h, and then carrying out vacuum drying for 48h to prepare a green body;
(5) and (3) uniformly placing the green body prepared in the step (4) in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot pressing furnace, gradually heating to 900 ℃ at the heating rate of 1 ℃/min under the argon atmosphere, preserving heat for 30min, then gradually heating to 1800 ℃ at the heating rate of 15 ℃/min under the nitrogen pressure of 0.6MPa, and preserving heat for 2h to prepare the porous silicon nitride ceramic.
Analyzing the phase of the silicon nitride ceramic by using an X-ray diffractometer (XRD); the porosity and density of the sample are measured by an Archimedes drainage method; measuring the bending strength of the sample by using a universal testing machine; and observing the microstructure of the sample by using a scanning electron microscope. The performance parameters of the porous silicon nitride ceramics prepared in each example are detailed in table 1.
Table 1 shows the test properties of the sintered specimens according to the invention
As can be seen in connection with table 1: different raw material ratios, heat treatment time, pH values and temperature parameters can respectively prepare the silicon nitride ceramic material with 60.6-76.7% of porosity and 7.89-12.9 MPa of bending strength.
The phase of the oriented porous silicon nitride ceramic is analyzed by an X-ray diffractometer (XRD) to obtain the information of the crystal structure of the ceramic. The characterization results of examples two, four and six are shown in fig. 1, and it can be seen that: the sintering temperature is 1400 ℃, a small amount of diffraction peaks of beta-Si 3N4 appear, which indicates that a small amount of alpha-beta transformation occurs, and the main crystal phase of the alpha-Si 3N4 is still alpha-Si 3N 4; the diffraction peak of beta-Si 3N4 became stronger with increasing temperature, indicating that the content thereof increased and the conversion of alpha-beta was not completed up to 1600 ℃.
The SEM for example 10 is shown in FIG. 2. It can be seen that there are many pores on the SEM, whose pore structure resembles a trumpet flower, because the decomposition of supramolecular gels composed of melamine etc. promotes the formation of trumpet flower-like porous structures.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (6)
1. A preparation method of porous silicon nitride ceramic is characterized in that melamine is dissolved in methanol and a first part of deionized water, and white transparent liquid is obtained by heating in water bath; dissolving tetraethoxysilane in absolute ethyl alcohol and a second part of deionized water, stirring and heating to obtain a transparent solution, mixing a white transparent solution and the transparent solution, heating to 55-75 ℃, adding acid, continuously stirring, adjusting the pH value to form a gel, freezing the gel at-60-0 ℃ for 2-6 h by adopting a freeze drying process, then vacuum-drying for 8-48 h to obtain a green body, uniformly placing the green body in a graphite crucible coated with BN, placing the graphite crucible in a vacuum hot-pressing furnace, gradually heating to 700-900 ℃ at the heating rate of 0.5-1 ℃/min under the argon atmosphere, preserving heat for 30-60 min, gradually heating to 1400-1800 ℃ at the heating rate of 5-15 ℃/min under the nitrogen pressure of 0.2-0.6 MPa, preserving heat for 1-2 h, and obtaining a main crystal position as a channel after the green body is firstly sintered under the argon atmosphere and secondly sintered under the nitrogen atmosphere, The dendritic crystal position is structural porous silicon nitride ceramics of a cavity Helmholtz array.
2. Process according to claim 1, characterized in that the melamine: methanol: the mole ratio of the first portion of deionized water is 1: (8-10): (40-50), heating to 60-75 ℃ in a water bath, and continuously reacting for 15-25 min to obtain white transparent liquid.
3. The method of claim 1, wherein the ratio of ethyl orthosilicate: anhydrous ethanol: the molar ratio of the second part of deionized water is 1: (1-1.5): (1.5-2), heating to 55-75 ℃ under continuous stirring, and continuously reacting for 20-30 min to obtain a transparent solution.
4. The process according to claim 1, characterized in that (melamine + methanol + first portion of deionized water): the volume ratio of the ethyl orthosilicate, the absolute ethyl alcohol and the second part of deionized water is (1-1.5): 1.
5. the method according to claim 1, wherein the pH is 1.5 to 4.5.
6. The method of claim 1, wherein the acid is nitric acid, hydrochloric acid, or acetic acid.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910382733.9A CN110078519B (en) | 2019-05-09 | 2019-05-09 | Preparation method of porous silicon nitride ceramic |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910382733.9A CN110078519B (en) | 2019-05-09 | 2019-05-09 | Preparation method of porous silicon nitride ceramic |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110078519A CN110078519A (en) | 2019-08-02 |
| CN110078519B true CN110078519B (en) | 2021-07-27 |
Family
ID=67419301
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910382733.9A Active CN110078519B (en) | 2019-05-09 | 2019-05-09 | Preparation method of porous silicon nitride ceramic |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110078519B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102320856A (en) * | 2011-08-24 | 2012-01-18 | 中国科学院上海硅酸盐研究所 | Method for preparing porous silicon-nitride ceramic material |
| CN103304252A (en) * | 2013-06-13 | 2013-09-18 | 哈尔滨工业大学 | Preparation method of SiO2 aerogel/porous Si3N4 composite material |
| CN107746285A (en) * | 2017-10-18 | 2018-03-02 | 武汉科技大学 | A kind of three-dimensional porous nitride nano ceramics and preparation method thereof |
| CN108863394A (en) * | 2017-05-10 | 2018-11-23 | 中国科学院上海硅酸盐研究所 | A kind of method that gel pouring combination freeze-drying prepares porous ceramics |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60124205A (en) * | 1983-12-09 | 1985-07-03 | キヤタラー工業株式会社 | Sludge casting molding method of silicon nitride ceramics |
-
2019
- 2019-05-09 CN CN201910382733.9A patent/CN110078519B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102320856A (en) * | 2011-08-24 | 2012-01-18 | 中国科学院上海硅酸盐研究所 | Method for preparing porous silicon-nitride ceramic material |
| CN103304252A (en) * | 2013-06-13 | 2013-09-18 | 哈尔滨工业大学 | Preparation method of SiO2 aerogel/porous Si3N4 composite material |
| CN108863394A (en) * | 2017-05-10 | 2018-11-23 | 中国科学院上海硅酸盐研究所 | A kind of method that gel pouring combination freeze-drying prepares porous ceramics |
| CN107746285A (en) * | 2017-10-18 | 2018-03-02 | 武汉科技大学 | A kind of three-dimensional porous nitride nano ceramics and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110078519A (en) | 2019-08-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN105541306B (en) | A kind of aluminium oxide closed cell foamed ceramics and preparation method thereof of alumina fibre enhancing | |
| CN106278368A (en) | A kind of composite molecular sieve film and its preparation method and application | |
| CN103011817B (en) | Preparation method of yttrium-silicon-oxygen porous high-temperature ceramic material | |
| US9919975B2 (en) | Porous SiC ceramic and method for the fabrication thereof | |
| CN109251005B (en) | Preparation method of reinforced silica aerogel material | |
| CN101508592B (en) | Process for producing stephanoporate Si3N4 | |
| CN110105082A (en) | A kind of preparation method of fiber reinforced porous silicon nitride ceramic | |
| CN108686697A (en) | A kind of alginic acid alkali composite nitride carbon photocatalysis aerogel material and the preparation method and application thereof | |
| CN110745827B (en) | Preparation method of two-dimensional flaky SiC material | |
| CN105084878A (en) | Preparation method of acicular mullite porous ceramic block material with superhigh amount of porosity | |
| CN105251374A (en) | Preparation method of nano-scale surface defect seed crystal induced SAPO-34 molecular sieve membrane | |
| CN109574680A (en) | A kind of method that gas-solid reaction combination lqiuid phase sintering method prepares porous silicon nitride ceramic | |
| CN114804912A (en) | Method for preparing high-toughness high-temperature-resistant directionally-arranged silicon nitride monolithic porous ceramic | |
| CN110468453B (en) | Preparation method for in-situ growth of high-length-diameter-ratio mullite whiskers | |
| CN113511890A (en) | Zirconium pyrophosphate porous ceramic material based on foaming method and preparation method thereof | |
| Wang et al. | Effect of in situ synthesis of Si2N2O on microstructure and the mechanical properties of fused quartz ceramics | |
| CN110078519B (en) | Preparation method of porous silicon nitride ceramic | |
| CN110040995B (en) | Preparation method of high-temperature light tough mullite aggregate | |
| CN104386657A (en) | Preparation method of high-crystallinity boron nitride | |
| CN109133986A (en) | Porous composite ceramics of a kind of AlN-SiC based on foaming and preparation method thereof | |
| CN113716975A (en) | Method for preparing wood biomass porous silicon carbide through 3D printing and porous silicon carbide | |
| CN102140030B (en) | Method for preparing high-porosity nanocrystalline silicon carbide foam ceramic without sintering | |
| CN108947498B (en) | Preparation method of alumina-silicon carbide porous composite ceramic | |
| CN111116209A (en) | Directional porous silicon nitride honeycomb ceramic and rapid preparation method thereof | |
| CN104086183A (en) | Preparation method of porosity-controllable porous Si3N4 |
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 | ||
| TR01 | Transfer of patent right | ||
| TR01 | Transfer of patent right |
Effective date of registration: 20240709 Address after: 233000 room 0, unit 10, unit 0, B building, Wanda Plaza Apartment, bengshan, Bengbu, Anhui Patentee after: BENGBU KERUIDA MACHINERY DESIGN Co.,Ltd. Country or region after: China Address before: No. 259, West 2nd Ring Road, Xi'an City, Shaanxi Province Patentee before: XI'AN AERONAUTICAL University Country or region before: China |