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CN-121974718-A - High-temperature-resistant low-pressure-drop ceramic filter material and preparation method and application thereof

CN121974718ACN 121974718 ACN121974718 ACN 121974718ACN-121974718-A

Abstract

The invention discloses a high-temperature-resistant low-pressure-drop ceramic filter material and a preparation method and application thereof, and belongs to the field of ceramic filter material preparation. The method comprises the steps of taking ultra-light silicon nitride nanowire foam as a matrix, firstly depositing silicon carbide in situ through CVI, wherein the CVI can strengthen the nanowire foam by forming bonding nodes among the nanowires on one hand, and can form gradient distributed pore diameters inside and outside the foam, namely gradually reducing the pore diameter from a foam core to the outer surface, and secondly, cutting the ultra-light silicon nitride nanowire foam subjected to chemical vapor infiltration strengthening treatment along the thickness direction, so that the thickness of a sample can be effectively reduced, and finally, the porous ceramic material with high strength, high porosity and low pressure drop characteristic is prepared. Breaks through the bottleneck that the porosity and strength of the traditional honeycomb ceramics are difficult to cooperatively promote, and has good application prospect in the fields of high-temperature tail gas filtration, diesel engine carbon particle filtration materials, metal liquid impurity filtration and the like.

Inventors

  • WANG HONGJIE
  • LIU ZHIPENG
  • Lu de
  • SU LEI
  • NIU MIN
  • PENG KANG

Assignees

  • 西安交通大学

Dates

Publication Date
20260505
Application Date
20260128

Claims (10)

  1. 1. The preparation method of the high-temperature-resistant low-pressure-drop ceramic filter material is characterized by comprising the following steps of: 1) Depositing silicon carbide on the surface of the nanowire of the ultra-light silicon nitride nanowire foam by using the ultra-light silicon nitride nanowire foam as a matrix through a chemical vapor infiltration method; 2) Cutting the ultra-light silicon nitride nanowire foam subjected to chemical vapor infiltration strengthening treatment along the thickness direction; 3) Polishing, cleaning and drying the cut product to obtain a sample; 4) And carrying out high-temperature heat preservation treatment on the sample, and cooling to obtain the low-pressure-drop ceramic filter material.
  2. 2. The method for preparing the high-temperature-resistant low-pressure-drop ceramic filter material according to claim 1, wherein the ultra-light silicon nitride nanowire foam is a silicon nitride nanowire with the diameter of 30-150 nm or a porous three-dimensional network structure formed by a plurality of silicon nitride nanowires with the diameter of 30-150 nm, and the density of the ultra-light silicon nitride nanowire foam is 1-5 mg/cm 3 .
  3. 3. The method for preparing the high-temperature-resistant low-pressure-drop ceramic filter material according to claim 1, wherein in the step 1), a precursor used for depositing silicon carbide by a chemical vapor infiltration method is methyltrichlorosilane, the deposition pressure is 800-4000 Pa, the deposition temperature is 900-1200 ℃, and the deposition time period is 3-20 h.
  4. 4. The method for preparing a high temperature resistant low pressure drop ceramic filter material according to claim 1, wherein in step 2), mechanical cutting is adopted to cut the pore diameter of the low pressure drop porous ceramic from a gradient distribution of 'small-large-small' to a gradient distribution of 'large-small' or 'small-large' along the thickness direction.
  5. 5. The method for preparing the high-temperature-resistant low-pressure-drop ceramic filter material according to claim 1, wherein in the step 3), the cut product is sequentially polished by using 800-mesh, 1000-mesh and 2000-mesh sand paper, the ultrasonic cleaning is performed for 2-5 times for 10 minutes each time, and the drying is performed at 80-100 ℃ for 1-6 h times.
  6. 6. The method for preparing the high-temperature-resistant low-pressure-drop ceramic filter material according to claim 1, wherein in the step 4), the sample is subjected to high-temperature heat preservation at 1000-1200 ℃ for 0.5-4 h hours, and after heat preservation is finished, the temperature is reduced to 500 ℃ or below, so that the target product is prepared.
  7. 7. The high temperature resistant low pressure drop ceramic filter material prepared by the preparation method of the high temperature resistant low pressure drop ceramic filter material according to any one of claims 1 to 6, which is characterized in that the low pressure drop ceramic filter material has a volume density of 50 to 900 mg/cm 3 , a porosity of 72 to 93 percent and an average pore diameter of 5 to 25 μm.
  8. 8. The ceramic filter material of claim 7, wherein the ceramic filter material has a compressive strength of 2-30 MPa, a maximum stable operating temperature of 1000 o C and a pressure drop of less than 5 kPa.
  9. 9. The high temperature and low pressure drop resistant ceramic filter material of claim 7, wherein the ceramic filter material does not fracture when thermally shocked 500 times at 950 o C.
  10. 10. Use of the ceramic filter material of any one of claims 7-9 for high temperature exhaust gas filtration, diesel carbon particulate filter material and metal liquid impurity filtration.

Description

High-temperature-resistant low-pressure-drop ceramic filter material and preparation method and application thereof Technical Field The invention belongs to the technical field of ceramic filter material preparation, and particularly relates to a high-temperature-resistant low-pressure-drop ceramic filter material, and a preparation method and application thereof. Background The existing high-temperature filtering material mainly comprises honeycomb ceramics, ceramic fiber mats, metal wire meshes, ceramic foam and the like, and can meet basic dust removal and purification requirements to a certain extent, but has a plurality of defects. For example, it is often difficult to work stably for a long period of time above 1000 ℃ because some glass fibers and low-end ceramic materials are susceptible to strength degradation or structural deformation at high temperatures. Meanwhile, the traditional honeycomb ceramics and dense fiber mats often generate higher pressure drop when the filtering efficiency is ensured, and the energy consumption of a fan and the running cost of a system are increased. Most ceramic substrates are of relatively large mass, resulting in increased equipment weight and maintenance inconvenience. In addition, once the honeycomb or woven structure is formed, the pore size distribution is difficult to adjust, and flexible geometric design means are lacked. In high added value applications such as metal melt purification or high-temperature metal powder filtration, currently common alumina ceramic foam and silicon carbide filter sheets are easy to crack or block under metal erosion and thermal shock, and the quality and continuous production of products are affected. Therefore, with urgent demands of industries such as metallurgy, chemical industry, aerospace, automobile exhaust purification, metal additive manufacturing and the like for energy conservation and emission reduction, high temperature stability, light weight and flexible design, the existing ceramic filter materials are difficult to meet comprehensive performance indexes of long-term high temperature resistance, low pressure drop, high porosity and high strength, so that a novel filter material is needed to solve the problems. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide a high-temperature-resistant low-pressure-drop ceramic filter material and a preparation method thereof, so as to solve the technical problem that the conventional ceramic filter material cannot have the performances of long-term high temperature resistance, low pressure drop, high porosity and high strength. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: The invention discloses a preparation method of a high-temperature-resistant low-pressure-drop ceramic filter material, which comprises the following steps: 1) Depositing silicon carbide on the surface of the nanowire of the ultra-light silicon nitride nanowire foam by using the ultra-light silicon nitride nanowire foam as a matrix through a chemical vapor infiltration method; 2) Cutting the ultra-light silicon nitride nanowire foam subjected to chemical vapor infiltration strengthening treatment along the thickness direction; 3) Polishing, cleaning and drying the cut product to obtain a sample; 4) And carrying out high-temperature heat preservation treatment on the sample, and cooling to obtain the high-temperature-resistant low-pressure-drop ceramic filter material. Preferably, the ultra-light silicon nitride nanowire foam is a silicon nitride nanowire with the diameter of 30-150 nm or a porous three-dimensional network structure formed by a plurality of silicon nitride nanowires with the diameter of 30-150 nm, and the density of the ultra-light silicon nitride nanowire foam is 1-5 mg/cm 3. Preferably, in the step 1), the precursor used for depositing the silicon carbide by a chemical vapor infiltration method is methyltrichlorosilane, the deposition pressure is 800-4000 Pa, the deposition temperature is 900-1200 ℃, and the deposition time is 3-20 h. Preferably, in step 2), mechanical cutting is used to cut the pore size of the ultralight silicon nitride nanowire foam from a gradient distribution of "small-large-small" to a gradient distribution of "large-small" or "small-large" in the thickness direction. Preferably, in the step 3), the cut product is sequentially polished by using 800-mesh sand paper, 1000-mesh sand paper and 2000-mesh sand paper, the ultrasonic cleaning is adopted for 2-5 times for 10 minutes each time, and the drying is carried out at 80-100 ℃ for 1-6 h times. Preferably, in the step 4), the sample is subjected to high-temperature heat preservation at 1000-1200 ℃ for 0.5-4 h hours, and after the heat preservation is finished, the temperature is reduced to 500 ℃ or below, so as to obtain the target product. The invention also discloses a high-temperature-resistant low-pres