CN115959921A - Low-temperature in-situ synthesis method of silicon nitride whisker film layer surface modified mullite honeycomb ceramic and product prepared by same - Google Patents
Low-temperature in-situ synthesis method of silicon nitride whisker film layer surface modified mullite honeycomb ceramic and product prepared by same Download PDFInfo
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Abstract
The invention discloses a low-temperature in-situ synthesis method of mullite honeycomb ceramic modified on the surface of a silicon nitride whisker film layer and a product prepared by the method. The invention has the advantages of easily obtained raw materials, simple process, low firing temperature and excellent product performance, and has important significance for improving the quality of mullite honeycomb ceramics and saving the product cost, thereby having wide market prospect and being beneficial to popularization and application and the progress and development of industrial technology.
Description
Technical Field
The invention relates to the technical field of ceramic materials, in particular to a low-temperature in-situ synthesis method of silicon nitride whisker film layer surface modified mullite honeycomb ceramic and a product prepared by the method.
Background
A large amount of high-temperature flue gas generated by industries such as metallurgy, building materials, electric power and the like contains a large amount of unused heat energy every year, and a porous material similar to honeycomb ceramics is needed for heat energy recovery. The mullite honeycomb ceramic is applied to heat energy recovery due to the outstanding advantages of high refractoriness, strong corrosion resistance, good mechanical property, strong thermal stability and the like. However, because the high-temperature flue gas has high dust content, dust particles scour the pipe wall of the heat exchanger and adhere to the surface of a heat exchange material during heat exchange, and even deposit and block problems occur, so that the service life and the heat exchange efficiency of the heat exchange equipment are greatly influenced.
After the traditional mullite honeycomb ceramic works for a long time, dust is still easily sucked into micropores in the wall of the pore channel, and the necks of the micropores are blocked, so that the porosity of the honeycomb ceramic is reduced, the pressure loss is increased, the treatment efficiency of filtering dust-containing waste gas is reduced, and the backwashing regeneration performance is poor. Therefore, the surface of the honeycomb ceramic needs to be modified by adopting an advanced porous coating technology, the pore diameter of the membrane layer is finer than that of the carrier, fine dust can be effectively prevented from entering pore channels, and the regenerability and the service life of the filter during long-term operation are improved. The common membrane material at present is gamma-Al 2 O 3 However, they have disadvantages such as a high thermal expansion coefficient (poor compatibility with the honeycomb ceramic substrate), poor thermal stability (easy phase transition), and low strength. Therefore, there is a need to find a new oneThe membrane material is replaced.
If the silicon nitride whisker can be compounded with mullite honeycomb ceramic, the silicon nitride whisker is formed into a braided body and coated on the surface of the mullite honeycomb ceramic, so that the pore diameter smaller than that of a honeycomb ceramic carrier can be formed, and the specific surface area, the thermal conductivity and the thermal shock resistance of the mullite honeycomb ceramic carrier are improved. However, silicon nitride whiskers are expensive to manufacture and the synthesis temperature is high. Therefore, it is necessary to provide a method for preparing a silicon nitride whisker film layer with low cost and low synthesis temperature, so as to improve various properties of the mullite honeycomb ceramic material.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a low-temperature in-situ synthesis method of mullite honeycomb ceramic modified on the surface of a silicon nitride whisker film layer. The invention also aims to provide a product prepared by the low-temperature in-situ synthesis method of the mullite honeycomb ceramic modified by the silicon nitride whisker coating surface.
The purpose of the invention is realized by the following technical scheme:
the invention provides a low-temperature in-situ synthesis method of modified mullite honeycomb ceramic on the surface of a silicon nitride whisker film layer, which takes a base material, a bonding agent, a lubricant and a reaction base material as raw materials;
the base material consists of 50-70 wt% of aluminosilicate mineral, 0-15 wt% of siliceous raw material, 5-15 wt% of metal siliceous raw material, 5-10 wt% of metal aluminous raw material, 5-15 wt% of carbonaceous raw material, 0.1-1 wt% of seed crystal and 0.1-1 wt% of catalyst;
the binding agent is alkaline silica sol or the combination of the alkaline silica sol and carboxymethyl cellulose (CMC) or hydroxypropyl methyl cellulose (HPMC), and the dosage of the binding agent is 5-7 wt% of the base material; the dosage of the lubricant is 3-5 wt% of the base material;
the reaction base material consists of 50-70 wt% of siliceous material, 20-30 wt% of metal siliceous material and 10-20 wt% of metal aluminous material;
the preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricating agent and 15-16 wt% of water relative to the base materials, stirring, pugging, extruding, forming and carrying out secondary microwave drying to obtain a green body, wherein the first microwave drying is carried out until the moisture content of the green body is 5-8%, standing for 10-12 hours, and then carrying out secondary microwave drying until the moisture content of the final green body is less than 1%; and then placing the green body on a reaction base material in a tubular furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tubular furnace, introducing nitrogen atmosphere for sintering, and respectively keeping the temperature at 150 ℃ and 400-700 ℃ for 0.5-1 h when the temperature is raised, wherein the sintering temperature is 1300-1400 ℃, and the sintering time is 1-3 h, so as to obtain the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
Furthermore, the aluminosilicate mineral is one, two, three or four of kaolin, ball clay, andalusite, sillimanite, kyanite and bauxite; the siliceous material is one or the combination of rice hull powder, quartz powder and fused quartz powder; the metal siliceous material is one or the combination of metal silicon powder, polysilicon waste and monocrystalline silicon waste; the metal aluminum raw material is metal aluminum powder and/or aluminum scraps; the carbonaceous raw material is one or the combination of graphite powder, carbon powder and carbon black; the seed crystal is nano alpha-silicon nitride powder; the catalyst is one or the combination of transition metal Fe, co and Ni powder; the lubricant is edible oil.
Furthermore, the granularity of the aluminosilicate mineral is 80-700 meshes; the granularity of the siliceous raw material is 80 to 325 meshes; the granularity of the metal silicon material is 80-700 meshes; the granularity of the metal aluminum raw material is 80-325 meshes; the granularity of the carbonaceous raw material is 325 to 1000 meshes; the grain size of the seed crystal is 50-100 nanometers; the granularity of the catalyst is 700-1000 meshes.
In the scheme, the dosage of the alkaline silica sol in the bonding agent is 3-5 wt% of the base material.
Using the silicon nitride whisker film layer surfaceThe product prepared by the low-temperature in-situ synthesis method of the surface-modified mullite honeycomb ceramic has the porosity of more than or equal to 55 percent and the specific surface area of more than or equal to 50m 2 The fracture strength is more than or equal to 60MPa, and the cracking is avoided after 30 times of thermal shock circulation at room temperature to 1000 ℃.
The invention has the following beneficial effects:
(1) The invention adopts a scheme of step and sectional pore forming, can improve the porosity and the specific surface area of the mullite honeycomb ceramic, and takes the pores as the growth space of the silicon nitride whiskers. The sectional pore-forming process is detailed as follows: firstly, after primary microwave drying, alkaline silica sol is used for adjusting the pH value to react with metallic aluminum to form a product H 2 Gas and Al (OH) 3 The gas release plays a role in pore forming; then, al (OH) is used at about 150 DEG C 3 The decomposition of (2) generates water vapor for pore-forming; secondly, respectively releasing structural water and silanol at 400-700 ℃ by utilizing aluminosilicate minerals and silica sol for polycondensation and dehydration to form pores; finally, the SiO content at the sintering temperature is utilized 2 The mineral of (2) and metallic aluminum, metallic silicon and carbonaceous raw materials are subjected to various nitriding reactions to generate SiO and CO gases for pore-forming. In short, pores can be uniformly distributed in the honeycomb ceramic by increasing the burning of the matrix at different temperatures to form pores, so that the porosity and the specific surface area are effectively improved, a channel is created for gas for synthesizing the crystal whisker to escape to the surface at the sintering temperature, a space is created for the crystal whisker to grow in the ceramic, and the quantity of the crystal whisker is increased.
(2) In order to reduce the synthesis temperature of the silicon nitride whisker film layer, the invention adopts the combination of seed crystal and catalyst, wherein, the nano alpha-silicon nitride powder is used as the seed crystal, which is beneficial to the deposition of SiO and CO and promotes the growth of the silicon nitride whisker; fe. Co and Ni transition metal powder is melted into liquid phase at the sintering temperature and can be used as a catalyst to promote alpha-silicon nitride seed crystal, siO, si and N 2 Dissolving and precipitating. The combination of the crystal seed and the catalyst reduces the initial synthesis temperature (above 1400 ℃ in the prior art) of the silicon nitride crystal whisker to 1240-1300 ℃ on one hand, and further improves the quantity of the crystal whisker (the content of alpha-silicon nitride is more than 30 wt%) by promoting various nitriding reactions on the other hand.
(3) The invention adopts a mode of synthesizing the silicon nitride whisker with the assistance of the reaction base material, so that gas (SiO) capable of synthesizing the silicon nitride whisker flows through holes of the honeycomb ceramic, supplements gas escape loss parts possibly caused by high porosity of the honeycomb ceramic, and also improves the quantity and specific surface area of a silicon nitride whisker film layer on the surface of the honeycomb ceramic.
(4) The silicon nitride crystal whiskers and the film layer thereof are cooperatively grown in the honeycomb ceramic and on the surface of the honeycomb ceramic, wherein the silicon nitride crystal whiskers in the honeycomb ceramic are beneficial to improving the mechanical strength, the heat transfer property and the thermal shock resistance of the material, the silicon nitride crystal whisker film layer grown on the surface of the honeycomb ceramic is beneficial to improving the specific surface area of the material, and the silicon nitride crystal whiskers grown from air holes in the honeycomb ceramic to the surface of the honeycomb ceramic are interwoven in the air holes, so that the silicon nitride crystal whiskers are excellent in binding property with a ceramic matrix.
(5) The invention adopts the mode of low-temperature in-situ synthesis to grow the silicon nitride whiskers and the film thereof, namely, the silicon nitride whisker film is grown in situ while mullite is synthesized in situ, and the honeycomb ceramic matrix + film can be obtained by one-time firing, thereby avoiding the second-step heat treatment required by the traditional coating method and simultaneously avoiding the use of high-cost silicon nitride whiskers.
(6) The invention has the advantages of easily obtained raw materials, simple process, low firing temperature and excellent product performance, and has important significance for improving the quality of mullite honeycomb ceramics and saving the product cost, thereby having wide market prospect and being beneficial to popularization and application and the progress and development of industrial technology.
Drawings
The invention will now be described in further detail with reference to the following examples and the accompanying drawings:
FIG. 1 is an XRD spectrum of a modified mullite honeycomb ceramic on the surface of a silicon nitride whisker film layer prepared by the embodiment of the invention;
FIG. 2 is a secondary electron image of a modified mullite honeycomb ceramic on the surface of a silicon nitride whisker film layer prepared by the example of the invention;
FIG. 3 is a schematic diagram of the reaction base material assisted synthesis of silicon nitride whiskers in an example of the invention.
Detailed Description
The first embodiment is as follows:
the embodiment relates to a low-temperature in-situ synthesis method for silicon nitride whisker film layer surface modified mullite honeycomb ceramics, which takes base materials, a bonding agent, a lubricating agent and reaction base materials as raw materials;
the base material comprises 20wt% of kaolin (80 meshes), 10wt% of ball clay (325 meshes), 20wt% of andalusite (700 meshes), 5wt% of quartz powder (180 meshes), 5wt% of rice hull powder (80 meshes), 15wt% of metal silicon powder (700 meshes), 5wt% of metal aluminum powder (180 meshes), 5wt% of aluminum skimmings (180 meshes), 14wt% of graphite powder (325 meshes), 0.5wt% of nano alpha-silicon nitride powder (50 nanometers) and 0.5wt% of Fe powder (700 meshes);
the binder is alkaline silica sol and CMC, the consumption is 3wt%, 2wt% of the base material separately; lubricant edible oil, which is used in an amount of 3wt% of the base material;
the reaction base material comprises 50wt% of rice hull powder (325 meshes), 20wt% of quartz powder (325 meshes), 20wt% of polycrystalline silicon waste (180 meshes) and 10wt% of aluminum scraps (180 meshes)
The preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricant and 15wt% of water relative to the base materials, stirring, pugging, extruding, forming, and performing secondary microwave drying to obtain a green body, wherein the green body is subjected to primary microwave drying until the moisture content of the green body is 5%, standing for 12 hours, and performing secondary microwave drying until the moisture content of the green body is less than 1%; and then placing the green body on a reaction base material in a tube furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tube furnace, introducing nitrogen atmosphere for sintering, and respectively keeping the temperature for 0.5h at 150 ℃ and 400 ℃ during temperature rise, wherein the sintering temperature is 1300 ℃ and the sintering time is 3h to obtain the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
The second embodiment:
the embodiment provides a low-temperature in-situ synthesis method of mullite honeycomb ceramic modified on the surface of a silicon nitride whisker film layer, which is characterized in that: taking a base material, a bonding agent, a lubricating agent and a reaction base material as raw materials;
the base material comprises 20wt% of kaolin (80 meshes), 10wt% of bauxite (325 meshes), 20wt% of sillimanite (325 meshes), 20wt% of ball clay (700 meshes), 10wt% of fused quartz powder (325 meshes), 5wt% of polycrystalline silicon waste (180 meshes), 5wt% of metal aluminum powder (325 meshes), 3wt% of graphite powder (500 meshes), 3wt% of carbon black (1000 meshes), 3wt% of carbon powder (325 meshes), 0.5wt% of nano alpha-silicon nitride powder (100 nanometers), 0.25wt% of Fe powder (700 meshes) and 0.25wt% of Co powder (1000 meshes);
the binding agent is alkaline silica sol and HPMC, and the dosage is 5wt% and 2wt% of the base material respectively; lubricant edible oil, which is used in an amount of 5wt% of the base material;
the reaction base material comprises 50wt% of quartz powder (325 meshes), 10wt% of polycrystalline silicon waste (180 meshes), 10wt% of monocrystalline silicon waste (325 meshes), 10wt% of metal silicon powder (700 meshes) and 20wt% of metal aluminum powder (325 meshes);
the preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricant and 16wt% of water relative to the base materials, stirring, pugging, extruding, forming, and performing secondary microwave drying to obtain a green body, wherein the green body is subjected to primary microwave drying until the moisture content of the green body is 7%, standing for 11 hours, and performing secondary microwave drying until the moisture content of the green body is less than 1%; and then placing the green body on a reaction base material in a tubular furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tubular furnace, introducing nitrogen atmosphere for sintering, and respectively keeping the temperature at 150 ℃ and 700 ℃ for 1h, the sintering temperature is 1350 ℃ and the sintering time is 2h when the temperature is raised, so as to obtain the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
Example three:
the embodiment provides a low-temperature in-situ synthesis method of modified mullite honeycomb ceramics on the surface of a silicon nitride whisker film layer, which is characterized by comprising the following steps of: taking a base material, a bonding agent, a lubricating agent and a reaction base material as raw materials;
the base material comprises 30wt% of kaolin (500 meshes), 40wt% of kyanite (700 meshes), 12wt% of metal silicon powder (325 meshes), 10wt% of metal aluminum powder (150 meshes), 5wt% of graphite powder (400 meshes), 1wt% of nano alpha-silicon nitride powder (50 nanometers) and 1wt% of Ni powder (900 meshes);
the binding agent is alkaline silica sol and HPMC, and the dosage is respectively 4wt% and 3wt% of the base material; lubricant edible oil, which is used in an amount of 5wt% of the base stock;
the reaction base material comprises 60wt% of quartz powder (700 meshes), 30wt% of metal silicon powder (700 meshes) and 10wt% of metal aluminum powder (180 meshes);
the preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricant and 16wt% of water relative to the base materials, stirring, pugging, extruding, forming, and performing secondary microwave drying to obtain a green body, wherein the green body is subjected to primary microwave drying until the moisture content of the green body is 8%, standing for 10 hours, and performing secondary microwave drying until the moisture content of the green body is less than 1%; and then placing the green body on a reaction base material in a tubular furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tubular furnace, introducing nitrogen atmosphere for sintering, and respectively keeping the temperature for 1h at 150 ℃ and 500 ℃ during temperature rise, wherein the sintering temperature is 1400 ℃ and the sintering time is 1h, so as to obtain the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
Example four:
the embodiment provides a low-temperature in-situ synthesis method of mullite honeycomb ceramic modified on the surface of a silicon nitride whisker film layer, which is characterized in that: taking a base material, a bonding agent, a lubricating agent and a reaction base material as raw materials;
the base material comprises 50wt% of bauxite (700 meshes), 5wt% of quartz powder (180 meshes), 5wt% of fused quartz powder (80 meshes), 5wt% of rice hull powder (325 meshes), 6wt% of polycrystalline silicon waste (80 meshes), 6wt% of monocrystalline silicon waste (325 meshes), 10wt% of metal aluminum powder (80 meshes), 12wt% of carbon powder (325 meshes), 0.5wt% of nano alpha-silicon nitride powder (50 nanometers) and 0.5wt% of Co powder (1000 meshes);
the binding agent is alkaline silica sol and HPMC, the dosage is 3wt% and 3wt% of the base material respectively; lubricant edible oil, which is used in an amount of 4wt% of the base material;
the reaction base material comprises 20wt% of rice hull powder (325 meshes), 20wt% of quartz powder (700 meshes), 30wt% of fused quartz powder (180 meshes), 10wt% of polycrystalline silicon waste (325 meshes), 5wt% of monocrystalline silicon waste (180 meshes), 5wt% of metal silicon powder (700 meshes) and 10wt% of aluminum scraps (80 meshes);
the preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricant and 16wt% of water relative to the base materials, stirring, pugging, extruding, forming, and performing secondary microwave drying to obtain a green body, wherein the green body is subjected to primary microwave drying until the moisture content of the green body is 6%, standing for 10 hours, and performing secondary microwave drying until the moisture content of the green body is less than 1%; and then placing the green body on a reaction base material in a tubular furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tubular furnace, introducing nitrogen atmosphere for sintering, and respectively keeping the temperature at 150 ℃ and 600 ℃ for 0.5h when the temperature is raised, wherein the sintering temperature is 1360 ℃ and the sintering time is 2h, so as to obtain the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
Example five:
the embodiment provides a low-temperature in-situ synthesis method of mullite honeycomb ceramic modified on the surface of a silicon nitride whisker film layer, which is characterized in that: taking a base material, a bonding agent, a lubricating agent and a reaction base material as raw materials;
the base material comprises 30wt% of kaolin (325 meshes), 29wt% of ball clay (700 meshes), 5wt% of rice hull powder (150 meshes), 2wt% of polycrystalline silicon waste (240 meshes), 3wt% of monocrystalline silicon waste (325 meshes), 5wt% of metal silicon powder (700 meshes), 10wt% of metal aluminum powder (325 meshes), 5wt% of graphite powder (325 meshes), 5wt% of carbon black (1000 meshes), 0.5wt% of nano alpha-silicon nitride powder (50 nanometers), 0.2wt% of Co powder (700 meshes), 0.2wt% of Fe powder (325 meshes) and 0.1wt% of Ni powder (1000 meshes);
the binding agent is alkaline silica sol and HPMC, the dosage is 3wt% and 2wt% of the base material respectively; lubricant edible oil, which is used in an amount of 5wt% of the base stock;
the reaction base material comprises 30wt% of rice hull powder (325 meshes), 25wt% of quartz powder (700 meshes), 10wt% of polycrystalline silicon waste (325 meshes), 20wt% of monocrystalline silicon waste (500 meshes), 10wt% of metal aluminum powder (180 meshes) and 5wt% of aluminum skimmings (180 meshes);
the preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricant and 16wt% of water relative to the base materials, stirring, pugging, extruding, forming, and performing secondary microwave drying to obtain a green body, wherein the green body is subjected to primary microwave drying until the moisture content of the green body is 6%, standing for 11 hours, and performing secondary microwave drying until the moisture content of the green body is less than 1%; and then placing the green body on a reaction base material in a tubular furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tubular furnace, respectively preserving heat for 0.5h at 150 ℃ and 450 ℃ when heating, introducing nitrogen atmosphere for sintering, wherein the sintering temperature is 1340 ℃ and the sintering time is 2.5h, and obtaining the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
Respectively taking a silicon nitride crystal whisker synthesized without the assistance of a reaction base material (namely, gas directly passes through a honeycomb ceramic through hole and does not pass through the reaction base material), a nano alpha-silicon nitride crystal seed is not added, and a transition metal (Fe, co and Ni) catalyst is not added (other conditions are the same as those of the first embodiment) as a first comparative example, a second comparative example and a third comparative example; taking the fourth comparative example which is not treated by adopting a secondary microwave drying process and standing for 10-12 h, and carrying out primary microwave drying until the moisture content of the final green body is less than 1% (other conditions are the same as those in the second example); the fifth comparative example was conducted by replacing CMC or HPMC with the binder without using alkaline silica sol (the other conditions were the same as those in the examples). The properties and the content of α -silicon nitride of mullite honeycomb ceramics prepared in the examples and comparative examples of the present invention are shown in table 1.
TABLE 1 Properties and nitride contents of mullite honeycomb ceramics obtained in examples and comparative examples of the present invention
Wherein, the content of the alpha-silicon nitride is detected by adopting a K value method, and alpha-corundum is taken as a reference substance.
As can be seen from Table 1, the mullite honeycomb ceramics modified on the surface of the silicon nitride whisker film layer prepared by the embodiment of the invention all have high porosity, high specific surface area and high silicon nitride content.
Comparing the data of the first comparative example with the first comparative example, it can be seen that the silicon nitride content of the sample obtained in the first comparative example is reduced without the auxiliary synthesis using the reaction base material of the present invention, because a part of the SiO gas in the honeycomb ceramic is lost due to the high porosity of the honeycomb ceramic during the sintering process in the atmosphere, and thus the lost part needs to be replenished by the reaction base material; as can be seen from the data of comparative example I, comparative example II and comparative example III, the effect of promoting silicon nitride synthesis is not achieved by using the seed crystal or the catalyst aloneIf the alpha-silicon nitride is used in a composite way, the initial synthesis temperature of the alpha-silicon nitride is more than 1400 ℃, so that the combination of seed crystal and catalyst is necessary; comparing the data of example two with comparative example four, it can be seen that the alkaline water remaining after drying reacts with metallic aluminum to release gas and Al (OH) 3 Indexes such as porosity, specific surface area and silicon nitride content are all inferior to those of a sample subjected to standing reaction treatment, which shows that the improvement of the porosity is also helpful for in-situ synthesis of the silicon nitride whisker; as can be seen from the data of comparative example III and comparative example V, the alkaline silica sol is absent due to the absence of the metal aluminum forming gas and Al (OH) 3 The porosity, specific surface area and silicon nitride content of the sample are also reduced, since these reactions do not occur without the presence of the alkaline silica sol.
The mullite honeycomb ceramic prepared by the embodiment of the invention has the advantages that the surface of the silicon nitride whisker film layer is modified, as shown in figure 1, the phases of the mullite honeycomb ceramic are only mullite and silicon nitride; as shown in fig. 2, the silicon nitride whiskers are distributed in the honeycomb ceramic and on the surface of the honeycomb ceramic to form a film layer, which has the functions of increasing the specific surface area and reducing the minimum pore diameter of the surface; as shown in fig. 3, the embodiment of the present invention adopts a reaction base material assisted synthesis manner, through holes of the honeycomb ceramic are arranged in parallel to the horizontal direction, and SiO generated by the reaction base material flows through the through holes of the honeycomb ceramic.
Claims (6)
1. A low-temperature in-situ synthesis method of mullite honeycomb ceramic modified on the surface of a silicon nitride whisker film layer is characterized by comprising the following steps: taking a base material, a bonding agent, a lubricating agent and a reaction base material as raw materials;
the base material consists of 50 to 70 weight percent of aluminosilicate mineral, 0 to 15 weight percent of siliceous material, 5 to 15 weight percent of metal siliceous material, 5 to 10 weight percent of metal aluminous material, 5 to 15 weight percent of carbonaceous material, 0.1 to 1 weight percent of seed crystal and 0.1 to 1 weight percent of catalyst;
the binding agent is alkaline silica sol or the combination of the alkaline silica sol and carboxymethyl cellulose or hydroxypropyl methyl cellulose, and the dosage of the binding agent is 5 to 7 weight percent of the base material; the dosage of the lubricant is 3-5 wt% of the base material;
the reaction base material consists of 50-70 wt% of siliceous material, 20-30 wt% of metal siliceous material and 10-20 wt% of metal aluminous material;
the preparation method comprises the following steps: mixing the base materials, adding a bonding agent, uniformly mixing, adding a lubricant and 15-16 wt% of water relative to the base materials, stirring, pugging, extruding, forming, and performing secondary microwave drying to obtain a green body, wherein the green body is subjected to primary microwave drying until the moisture content of the green body is 5-8%, standing for 10-12 hours, and performing secondary microwave drying until the moisture content of the green body is less than 1% finally; and then placing the green body on a reaction base material in a tubular furnace, wherein the through hole of the green body is parallel to the ventilation direction of the tubular furnace, introducing nitrogen atmosphere for sintering, and respectively keeping the temperature at 150 ℃ and 400-700 ℃ for 0.5-1 h when the temperature is raised, wherein the sintering temperature is 1300-1400 ℃, and the sintering time is 1-3 h, so as to obtain the silicon nitride whisker film layer surface modified mullite honeycomb ceramic.
2. The low-temperature in-situ synthesis method of the silicon nitride whisker film layer surface modified mullite honeycomb ceramic as claimed in claim 1, wherein the method comprises the following steps: the aluminosilicate minerals are one, two, three or four of kaolin, ball clay, andalusite, sillimanite, kyanite and bauxite; the siliceous raw material is one or the combination of rice hull powder, quartz powder and fused quartz powder; the metal siliceous raw material is one or the combination of metal silicon powder, polysilicon waste and monocrystalline silicon waste; the metal aluminum raw material is metal aluminum powder and/or aluminum scraps; the carbonaceous raw material is one or the combination of graphite powder, carbon powder and carbon black; the seed crystal is nano alpha-silicon nitride powder; the catalyst is one or the combination of transition metal Fe, co and Ni powder; the lubricant is edible oil.
3. The low-temperature in-situ synthesis method of the silicon nitride whisker film layer surface modified mullite honeycomb ceramic as claimed in claim 1 or 2, wherein the method comprises the following steps: the granularity of the aluminosilicate minerals is 80-700 meshes; the particle size of the siliceous raw material is 80 to 325 meshes; the granularity of the metal silicon material is 80-700 meshes; the granularity of the metal aluminum raw material is 80-325 meshes; the granularity of the carbonaceous raw material is 325 to 1000 meshes; the grain size of the seed crystal is 50-100 nanometers; the granularity of the catalyst is 700-1000 meshes.
4. The low-temperature in-situ synthesis method of the silicon nitride whisker film layer surface modified mullite honeycomb ceramic as claimed in claim 1, wherein the method comprises the following steps: the dosage of the alkaline silica sol in the binding agent is 3-5 wt% of the base material.
5. The product prepared by the low-temperature in-situ synthesis method of the silicon nitride whisker film layer surface modified mullite honeycomb ceramic in the claims 1-4.
6. The product of claim 5, wherein: the surface of the silicon nitride whisker film layer is modified mullite honeycomb ceramic, the porosity of which is more than or equal to 55 percent, and the specific surface area of which is more than or equal to 50m 2 The fracture strength is more than or equal to 60MPa, and the cracking is avoided after 30 times of thermal shock circulation at room temperature to 1000 ℃.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008239434A (en) * | 2007-03-28 | 2008-10-09 | Nagoya Institute Of Technology | Manufacturing method of ceramic porous body and ceramic porous body |
| CN103992099A (en) * | 2014-05-20 | 2014-08-20 | 陕西科技大学 | Method for preparing environment-friendly honeycomb ceramic heat accumulator by use of waste slag |
| CN108275969A (en) * | 2018-01-31 | 2018-07-13 | 景德镇陶瓷大学 | It is a kind of to utilize the mullite silicon carbide whisker composite ceramic material and preparation method thereof that natural minerals are raw material |
| CN108276017A (en) * | 2018-01-31 | 2018-07-13 | 景德镇陶瓷大学 | It is a kind of to utilize corundum-silicon carbide whisker composite ceramic material and preparation method thereof that natural minerals are raw material |
| CN114853500A (en) * | 2022-04-29 | 2022-08-05 | 中国科学院上海硅酸盐研究所 | Silicon nitride and silicon carbide combined complex phase ceramic and preparation method and application thereof |
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| JP2008239434A (en) * | 2007-03-28 | 2008-10-09 | Nagoya Institute Of Technology | Manufacturing method of ceramic porous body and ceramic porous body |
| CN103992099A (en) * | 2014-05-20 | 2014-08-20 | 陕西科技大学 | Method for preparing environment-friendly honeycomb ceramic heat accumulator by use of waste slag |
| CN108275969A (en) * | 2018-01-31 | 2018-07-13 | 景德镇陶瓷大学 | It is a kind of to utilize the mullite silicon carbide whisker composite ceramic material and preparation method thereof that natural minerals are raw material |
| CN108276017A (en) * | 2018-01-31 | 2018-07-13 | 景德镇陶瓷大学 | It is a kind of to utilize corundum-silicon carbide whisker composite ceramic material and preparation method thereof that natural minerals are raw material |
| CN114853500A (en) * | 2022-04-29 | 2022-08-05 | 中国科学院上海硅酸盐研究所 | Silicon nitride and silicon carbide combined complex phase ceramic and preparation method and application thereof |
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