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CN-121990816-A - Alumina fiber reinforced alumina-based composite material and ultrasonic-assisted impregnation preparation method thereof

CN121990816ACN 121990816 ACN121990816 ACN 121990816ACN-121990816-A

Abstract

The invention relates to an alumina fiber reinforced alumina-based composite material and an ultrasonic auxiliary impregnation preparation method thereof, which comprises the steps of preprocessing alumina fiber cloth to prepare alumina ceramic slurry; placing the pretreated alumina fiber in the alumina ceramic slurry, dipping under the action of ultrasonic, laying in a lamination way, hot pressing and drying to obtain a green body, solidifying and sintering the green body to form a rough blank, dipping the rough blank by adopting alumina sol, drying after dipping, sintering after drying, and repeating dipping, drying and sintering processes to obtain the alumina fiber reinforced alumina-based composite material. According to the invention, through the composite technology combining ultrasonic auxiliary impregnation and alumina sol cyclic impregnation, the filling impregnation effect of the slurry on the fibers is remarkably improved, so that the slurry uniformly permeates into the fiber bundles and the gaps between fabrics, the defect of pores in the materials is reduced, and the density and mechanical properties of the composite material are greatly improved.

Inventors

  • ZOU XUEGANG
  • Han Shuaikang
  • HU JIANBAO

Assignees

  • 上海瑞华晟新材料有限公司

Dates

Publication Date
20260508
Application Date
20260309

Claims (10)

  1. 1. The ultrasonic-assisted impregnation preparation method of the alumina fiber reinforced alumina-based composite material is characterized by comprising the following steps of: s1, pretreating alumina fiber cloth to remove a surface organic coating to obtain pretreated alumina fiber cloth, and mixing alumina powder, a solvent and a dispersing agent to obtain alumina ceramic slurry, wherein the particle size of the alumina powder is 0.1-1 mu m; S2, arranging the pretreated alumina fibers in the alumina ceramic slurry, and soaking under the ultrasonic action to disperse alumina powder into the alumina fibers to obtain an alumina cloth prepreg tape; s3, laying the alumina cloth prepreg tape in a laminated manner, and performing hot press drying on the blank body subjected to the laying to remove water in the blank body so as to obtain a green body; s4, solidifying and sintering the green body to form a rough blank; and S5, carrying out impregnation treatment on the rough blank by adopting alumina sol, drying after impregnation, sintering after drying, and repeating the processes of impregnation, drying and sintering to obtain the alumina fiber reinforced alumina-based composite material.
  2. 2. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S1, the alumina fiber cloth is pre-treated by heating to 500-700 ℃ at 5-10 ℃ per min and maintaining for 1-2 hours.
  3. 3. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S1, the solvent is alumina sol, silica sol or mullite sol, and/or the dispersing agent is polyethylene glycol, polyacrylamide, ammonia citrate or polyethyleneimine, and/or the mixing ratio of alumina powder, solvent and dispersing agent is 40-60wt% 49-49.9wt% 0.1-1wt%.
  4. 4. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S1, the mixed alumina powder, solvent and dispersant are subjected to ball milling to obtain alumina ceramic slurry, wherein the ball milling speed is 200-500 rad/min, the ball milling time is 3-6 h, and ball milling beads are zirconia or alumina balls with the diameter of 3-5 mm, and the ball-to-material ratio is 2-4:1.
  5. 5. The method according to claim 1, wherein in the step S2, the ultrasonic frequency is 28 to 40khz, and the ultrasonic dipping time is 10 to 30 minutes.
  6. 6. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S2, single-layer or multi-layer pretreated alumina fiber cloth is subjected to ultrasonic impregnation, and/or tension of 10-30N is applied to the surface of the fiber cloth through rollers during ultrasonic impregnation so as to keep the fiber cloth flat and uniform in the impregnation process, and/or rolling treatment is performed after the impregnation is completed so as to remove redundant slurry and ensure the thickness of the prepreg tape to be uniform.
  7. 7. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S3, the total number of layers after the superposition of the alumina cloth prepreg tapes is 10-20, the pressure of hot press drying is 600-1000 KPa, the heating rate is 2-5 ℃ per minute, and the heat preservation is carried out for 6-10 hours after the temperature is raised to 100-150 ℃.
  8. 8. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S4, the sintering atmosphere is an air atmosphere or an inert atmosphere, the heating rate is 5-10 ℃ per minute, and the temperature is kept for 1-3 hours after the temperature is raised to 600-900 ℃.
  9. 9. The ultrasonic-assisted impregnation preparation method according to claim 1, wherein in the step S5, the solid content of the alumina sol is 20-40%, the particle size is 1-20 nm, the viscosity is less than or equal to 50 mPa.s, and/or the sintering temperature rising rate is 5-10 ℃ per minute, the sintering temperature is 800-1200 ℃, and/or the circulation is stopped until the weight of the final composite material is increased by less than or equal to 2% of the weight of the last composite material, and the total circulation densification times of the alumina ceramic composite material prepared by the method are less than or equal to 3 times.
  10. 10. An alumina fiber reinforced alumina-based composite obtained according to the ultrasound-assisted impregnation preparation method according to any one of claims 1 to 9.

Description

Alumina fiber reinforced alumina-based composite material and ultrasonic-assisted impregnation preparation method thereof Technical Field The invention relates to an alumina ceramic composite material, in particular to an alumina fiber reinforced alumina-based composite material and an ultrasonic auxiliary impregnation preparation method thereof. Background The alumina fiber reinforced alumina-based composite material (Al 2O3/Al2O3) is taken as a ceramic matrix composite material with excellent performance, and has great application potential in the fields with strict requirements on high temperature resistance of materials such as aerospace hot end components, high temperature industrial equipment and the like by virtue of the outstanding high temperature oxidation resistance, high strength and low density characteristics. Compared with a non-oxide ceramic matrix composite, the Al 2O3/Al2O3 composite also has excellent anti-oxidation corrosion capability, can effectively reduce fiber performance attenuation caused by oxidation, and can be stably served for a long time in a complex environment with water and oxygen coexisting, so that the composite becomes an ideal substitute material for hot end components in the fields of aerospace and the like. At present, a slurry method is generally adopted for preparing the Al 2O3/Al2O3 composite material. The method generally comprises the steps of brushing the prepared alumina ceramic slurry on the surface of a two-dimensional alumina fiber cloth by hands to form a prepreg, and then performing subsequent procedures such as layering, hot pressing, sintering and the like to finally prepare the Al 2O3/Al2O3 composite material. However, the conventional preparation method has two technical bottlenecks which are difficult to break through in the preparation stage of the prepreg, and seriously affects the performance and application effect of the final composite material: First, the process consistency is poor. The implementation of the manual brushing process is highly dependent on the experience of operators, so that the accurate control of the slurry coating uniformity cannot be realized, and the slurry in the prefabricated body is easily unevenly distributed. The problem directly causes thickness fluctuation of the composite material finished product, further causes performance difference among different batches of products and even the same batch of products, and is difficult to meet the severe requirement of high-end equipment on material performance stability. Secondly, the slurry permeation effect is limited. Because the alumina fiber has stronger bundling property, the internal structure of the fiber bundle is compact, and the alumina ceramic slurry with high solid content, which has higher viscosity and poor fluidity, is difficult to fully infiltrate into the fiber bundle only by means of pressure and capillary action applied by manual brushing. This allows the majority of the slurry to adhere only to the surface of the fiber cloth and to the larger pores between the fiber bundles, resulting in a large number of continuous unfilled pores within the fiber bundles after sintering. These pores become structural defects in the material, remarkably reduce the density of the composite material, and simultaneously have negative effects on the mechanical properties of the material, thereby limiting the application of the Al 2O3/Al2O3 composite material in a higher-requirement scene. Disclosure of Invention In order to solve the problems of uneven slurry distribution, insufficient penetration inside fiber bundles and the like in the manual brushing preparation of the Al 2O3/Al2O3 composite material in the prior art, the invention aims to provide an alumina fiber reinforced alumina-based composite material and an ultrasonic auxiliary impregnation preparation method thereof. The ultrasonic auxiliary impregnation preparation method of the alumina fiber reinforced alumina-based composite material comprises the following steps of S1, pretreating alumina fiber cloth to remove a surface organic coating to obtain pretreated alumina fiber cloth, mixing alumina powder, a solvent and a dispersing agent to obtain alumina ceramic slurry, wherein the particle size of the alumina powder is 0.1-1 mu m, S2, placing the pretreated alumina fiber in the alumina ceramic slurry, impregnating under the ultrasonic action to enable the alumina powder to be dispersed into the alumina fiber to obtain an alumina cloth prepreg tape, S3, laying the alumina cloth prepreg tape in a lamination mode, performing hot press drying on a blank body after layering to remove moisture in the blank body to obtain a green body, S4, solidifying and sintering the green body to form a coarse blank, S5, impregnating the coarse blank with alumina sol, drying after impregnation, sintering, and repeating impregnation, drying and sintering processes to obtain the alumina fiber reinforced alumina-based composite material.