阅读说明：本技术 一种致密的层状碳化硅陶瓷及其制备方法 (Compact layered silicon carbide ceramic and preparation method thereof ) 是由 张劲松 曹小明 杨永进 金鹏 徐奕辰 刘强 于 2020-05-20 设计创作，主要内容包括：本发明涉及层状陶瓷的制备技术,具体地说是一种致密的层状碳化硅陶瓷及其制备方法。层状碳化硅陶瓷以薄片状碳化硅陶瓷为基本单元,各基本单元以叠层方式利用分立式碳化硅陶瓷柱连接的三层以上结构；层状碳化硅陶瓷中,碳化硅陶瓷基本单元和碳化硅陶瓷柱的相对致密度≥99％；按重量百分比计,碳化硅陶瓷基本单元和碳化硅陶瓷柱各自的成份由90％～98％的碳化硅和10％～2％的硅组成,平均晶粒尺寸在50nm～50μm。本发明利用层状碳化硅陶瓷的层状结构间隙,将韧性相(如：金属、聚合物等)填充到层状结构间隙中,在承受冲击载荷时,可以改变裂纹的传输途径、扩展机制、降低材料对裂纹的敏感性,进而提高陶瓷的韧性。(The invention relates to a preparation technology of laminated ceramic, in particular to compact laminated silicon carbide ceramic and a preparation method thereof. The laminated silicon carbide ceramic is of a structure with more than three layers, wherein the laminated silicon carbide ceramic takes a flaky silicon carbide ceramic as a basic unit, and each basic unit is connected by using a discrete silicon carbide ceramic column in a laminated mode; in the layered silicon carbide ceramic, the relative density of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is more than or equal to 99 percent; the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 90-98 percent of silicon carbide and 10-2 percent of silicon by weight percent, and the average grain size is 50 nm-50 mu m. The invention utilizes the laminated structure gap of the laminated silicon carbide ceramic to fill the toughness phase (such as metal, polymer and the like) into the laminated structure gap, and can change the transmission path and the propagation mechanism of cracks and reduce the sensitivity of materials to the cracks when bearing impact load, thereby improving the toughness of the ceramic.)

1. The compact laminated silicon carbide ceramic is characterized in that the laminated silicon carbide ceramic takes a flaky silicon carbide ceramic as a basic unit, and each basic unit is of a structure with more than three layers connected by using discrete silicon carbide ceramic columns in a laminated mode; in the layered silicon carbide ceramic, the relative density of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is more than or equal to 99 percent; the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 90-98 percent of silicon carbide and 10-2 percent of silicon by weight percent, and the average grain size is 50 nm-50 mu m.

2. The method of preparing the dense layered silicon carbide ceramic according to claim 1, wherein the process for preparing the dense layered silicon carbide ceramic comprises: silicon carbide powder and resin with high carbon yield are used as raw materials, silicon carbide slurry is prepared → an aluminum foil is used as a template, the silicon carbide slurry is uniformly coated on one side or two sides of the aluminum foil → hot pressing densification → pyrolysis → reaction sintering → high temperature removal of residual silicon.

3. The method for preparing the dense, layered silicon carbide ceramic according to claim 2, comprising the steps of:

(1) preparation of silicon carbide slurry

60-20 wt% of silicon carbide powder, high carbon yield resin, curing agent and ethanol: 19 wt% -30 wt%: 1 wt% -10 wt%: 20-40 wt%, mixing silicon carbide powder, high carbon yield resin, curing agent and ethanol, mechanically stirring, ball milling and filtering to obtain slurry;

(2) coating hanger

Cutting the aluminum foil into required shapes and sizes, uniformly coating ceramics on one side or two sides, removing redundant slurry through a limiting scraper to enable the slurry to reach the designed thickness, and semi-curing the ceramic slurry in an air drying and heating mode to obtain a single-layer silicon carbide ceramic precursor;

(3) hot pressing densification

Sequentially laminating the single-layer silicon carbide ceramic precursors to obtain a laminated precursor; drilling holes on the laminated precursor according to the determined pore size and pore spacing distribution; putting the uniformly-distributed and drilled laminated precursor into a heated mold for high-temperature and high-pressure curing; in the heating and pressurizing process, part of semi-cured ceramic slurry coated on the surface of the aluminum foil flows into the pores of the pre-drilled holes of the laminated precursor under the action of high temperature and high pressure, the pores are filled and gradually cured to form uniformly distributed silicon carbide ceramic columns, so that the laminated precursors are connected together to obtain a compact laminated silicon carbide ceramic precursor;

(4) pyrolysis

Pyrolyzing the compact layered silicon carbide ceramic precursor under a protective atmosphere or a vacuum condition, wherein the protective atmosphere is argon, nitrogen or other inert gases, the heating rate is 1-5 ℃ per minute, the heating rate is 600-1200 ℃, and the heat is preserved for 0.5-2 hours to obtain a layered silicon carbide ceramic precursor carbon skeleton;

(5) reaction sintering

Siliconizing the pyrolyzed layered silicon carbide ceramic precursor carbon skeleton through reactive sintering, and placing a silicon block above the layered silicon carbide ceramic precursor carbon skeleton, wherein the size range of the silicon block is 20 mm-20 meshes, and the weight ratio of the silicon block to the carbon skeleton is (0.2-0.7): 1, performing the reaction under a protective atmosphere or a vacuum condition, wherein the protective atmosphere is argon, nitrogen or other inert gases, the heating rate is 5-15 ℃ per minute, the temperature is 1500-1900 ℃, and the temperature is kept for 0.5-4 hours, so as to obtain a silicon-rich layered silicon carbide ceramic material;

(6) high temperature removal of residual silicon

And (2) placing the silicon-rich layered silicon carbide ceramic material on a carbon-rich backing plate, wherein the carbon-rich backing plate is graphite paper, a graphite plate or carbon particles, performing heat preservation for 0.5-2 hours at the temperature rise rate of 5-15 ℃ per minute and the temperature of 1700-1900 ℃, and removing unreacted residual silicon in the interlayer gaps of the layered silicon carbide ceramic material to obtain the compact layered silicon carbide ceramic.

4. The method for preparing a dense layered silicon carbide ceramic according to claim 3, wherein in the step (1), the high carbon yield resin is one or more selected from epoxy resin, phenol resin, furfural resin, phenol/phenol furfural resin, the curing agent is p-toluenesulfonic acid, pentosan, oxalic acid or citric acid, the content of the curing agent is 1-20% of the weight of the resin, the average particle size of the silicon carbide powder is 10 nm-50 μm, and the weight of solids in the slurry is 30-80% of the total weight of the slurry.

5. The method for preparing a dense layered silicon carbide ceramic according to claim 3, wherein in the step (2), the heating manner in semi-curing is: the temperature is 50-100 ℃ and the time is 10 minutes-2 hours.

6. The method for preparing the dense layered silicon carbide ceramic according to claim 3, wherein in the step (3), the pressurizing pressure is 10 to 80MPa, the heating temperature is 100 to 300 ℃, the heating speed is 1 to 5 ℃, and the temperature is kept for 5 minutes to 3 hours in the hot-pressing densification process.

7. The method for preparing the dense layered silicon carbide ceramic as claimed in claim 3, wherein in the step (4), the pyrolysis temperature is in the range of 800 to 1000 ℃ and the temperature rise rate is 2 to 4 ℃/min during the pyrolysis.

8. The method for preparing the dense layered silicon carbide ceramic according to claim 3, wherein the aluminum foil is an aluminum foil for industrial packaging, and has a thickness of 0.1 to 1 mm; the aluminum foil needs to be removed from the pyrolyzed layered silicon carbide ceramic precursor, and two methods are adopted for removing the aluminum foil: firstly, the aluminum foil is gasified by utilizing the high temperature of reaction sintering to remove the aluminum foil; secondly, after pyrolysis, an acid-base solution is utilized to react with aluminum to remove the aluminum foil.

9. The method for preparing a dense layered silicon carbide ceramic according to claim 3, wherein when the weight ratio of the silicon block to the carbon skeleton in the step (5) is (0.2 to 0.3): 1, the process of removing the residual silicon at high temperature is cancelled.

Technical Field

The invention relates to a preparation technology of laminated ceramic, in particular to compact laminated silicon carbide ceramic and a preparation method thereof.

Background

The silicon carbide has excellent high hardness, high temperature resistance, oxidation resistance, acid and alkali corrosion resistance, thermal shock resistance and semiconductor characteristics, and is widely applied to the fields of armor protection, wear resistance, ablation resistance, sealing and the like. However, the inherent brittleness characteristic of silicon carbide ceramics limits their application as structural components. The layered silicon carbide ceramic provides sufficient design space for the design of the ceramic composite material, and is one of effective methods for toughening the ceramic.

At present, the layered ceramics are prepared by the following methods: tape casting, freeze-drying, electrophoretic deposition, 3D additive manufacturing, and the like.

The tape casting method is that ceramic slurry with good dispersion effect is prepared by ball milling and the like, wherein the ceramic slurry contains a certain amount of ceramic micro powder, solvent, organic additive, dispersant, adhesive and the like, thin layer prefabricated bodies are cast on thin plates made of different materials after degassing, the laminated structure prefabricated bodies are obtained by cutting and stacking, organic matters are removed at medium temperature, and laminated ceramic is obtained by high-temperature sintering.

Freeze drying, directional solidification of water or organic solvent in ceramic slurry in low temperature environment to form regular crystal structure, sublimation in vacuum state to remove water or organic solvent to leave layered structure, and high temperature sintering to obtain regularly arranged layered ceramic.

The electrophoretic deposition method is that under the action of a directional electric field, charged ceramic particles in suspension are deposited on an electrode with opposite polarity, and different charged ceramic particles are subjected to multiple cross deposition to form a layered structure.

The 3D additive manufacturing method can be used for manufacturing almost any material with a complex structure layer by layer in an additive manner by utilizing a calculation model and a 3D printing technology, and is an innovative material manufacturing method.

The invention content is as follows:

the invention aims to provide a compact layered silicon carbide ceramic and a preparation method thereof.

The technical scheme of the invention is as follows:

a compact laminated silicon carbide ceramic is characterized in that the laminated silicon carbide ceramic takes a flaky silicon carbide ceramic as a basic unit, and each basic unit is of a structure with more than three layers connected by using discrete silicon carbide ceramic columns in a laminated mode; in the layered silicon carbide ceramic, the relative density of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is more than or equal to 99 percent; the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 90-98 percent of silicon carbide and 10-2 percent of silicon by weight percent, and the average grain size is 50 nm-50 mu m.

The preparation method of the compact layered silicon carbide ceramic comprises the following steps: silicon carbide powder and resin with high carbon yield are used as raw materials, silicon carbide slurry is prepared → an aluminum foil is used as a template, the silicon carbide slurry is uniformly coated on one side or two sides of the aluminum foil → hot pressing densification → pyrolysis → reaction sintering → high temperature removal of residual silicon.

The preparation method of the compact layered silicon carbide ceramic specifically comprises the following steps:

(1) preparation of silicon carbide slurry

60-20 wt% of silicon carbide powder, high carbon yield resin, curing agent and ethanol: 19 wt% -30 wt%: 1 wt% -10 wt%: 20-40 wt%, mixing silicon carbide powder, high carbon yield resin, curing agent and ethanol, mechanically stirring, ball milling and filtering to obtain slurry;

(2) coating hanger

Cutting the aluminum foil into required shapes and sizes, uniformly coating ceramics on one side or two sides, removing redundant slurry through a limiting scraper to enable the slurry to reach the designed thickness, and semi-curing the ceramic slurry in an air drying and heating mode to obtain a single-layer silicon carbide ceramic precursor;

(3) hot pressing densification

Sequentially laminating the single-layer silicon carbide ceramic precursors to obtain a laminated precursor; drilling holes on the laminated precursor according to the determined pore size and pore spacing distribution; putting the uniformly-distributed and drilled laminated precursor into a heated mold for high-temperature and high-pressure curing; in the heating and pressurizing process, part of semi-cured ceramic slurry coated on the surface of the aluminum foil flows into the pores of the pre-drilled holes of the laminated precursor under the action of high temperature and high pressure, the pores are filled and gradually cured to form uniformly distributed silicon carbide ceramic columns, so that the laminated precursors are connected together to obtain a compact laminated silicon carbide ceramic precursor;

(4) pyrolysis

Pyrolyzing the compact layered silicon carbide ceramic precursor under a protective atmosphere or a vacuum condition, wherein the protective atmosphere is argon, nitrogen or other inert gases, the heating rate is 1-5 ℃ per minute, the heating rate is 600-1200 ℃, and the heat is preserved for 0.5-2 hours to obtain a layered silicon carbide ceramic precursor carbon skeleton;

(5) reaction sintering

Siliconizing the pyrolyzed layered silicon carbide ceramic precursor carbon skeleton through reactive sintering, and placing a silicon block above the layered silicon carbide ceramic precursor carbon skeleton, wherein the size range of the silicon block is 20 mm-20 meshes, and the weight ratio of the silicon block to the carbon skeleton is (0.2-0.7): 1, performing the reaction under a protective atmosphere or a vacuum condition, wherein the protective atmosphere is argon, nitrogen or other inert gases, the heating rate is 5-15 ℃ per minute, the temperature is 1500-1900 ℃, and the temperature is kept for 0.5-4 hours, so as to obtain a silicon-rich layered silicon carbide ceramic material;

(6) high temperature removal of residual silicon

And (2) placing the silicon-rich layered silicon carbide ceramic material on a carbon-rich backing plate, wherein the carbon-rich backing plate is graphite paper, a graphite plate or carbon particles, performing heat preservation for 0.5-2 hours at the temperature rise rate of 5-15 ℃ per minute and the temperature of 1700-1900 ℃, and removing unreacted residual silicon in the interlayer gaps of the layered silicon carbide ceramic material to obtain the compact layered silicon carbide ceramic.

In the step (1), the high-carbon-yield resin is one or more than two of epoxy resin, phenolic resin, furfural resin and phenolic/phenol furfural resin, the curing agent is p-toluenesulfonic acid, pentosan, oxalic acid or citric acid, the content of the curing agent is 1-20% of the weight of the resin, the average particle size of the silicon carbide powder is 10 nm-50 μm, and the weight of solid matters in the slurry is 30-80% of the total weight of the slurry.

In the step (2), the heating mode during semi-curing is as follows: the temperature is 50-100 ℃ and the time is 10 minutes-2 hours.

The preparation method of the compact layered silicon carbide ceramic comprises the step (3), wherein in the hot-pressing densification process, the pressurizing pressure is 10-80 MPa, the heating temperature is 100-300 ℃, the heating speed is 1-5 ℃, and the temperature is kept for 5 minutes-3 hours.

In the preparation method of the compact layered silicon carbide ceramic, in the step (4), in the pyrolysis process, the pyrolysis temperature is in the range of 800-1000 ℃, and the heating rate is 2-4 ℃/min.

According to the preparation method of the compact laminated silicon carbide ceramic, the aluminum foil is used for industrial packaging and is 0.1-1 mm thick; the aluminum foil needs to be removed from the pyrolyzed layered silicon carbide ceramic precursor, and two methods are adopted for removing the aluminum foil: firstly, the aluminum foil is gasified by utilizing the high temperature of reaction sintering to remove the aluminum foil; secondly, after pyrolysis, an acid-base solution is utilized to react with aluminum to remove the aluminum foil.

According to the preparation method of the compact layered silicon carbide ceramic, when the weight ratio of the silicon block to the carbon skeleton in the step (5) is (0.2-0.3): 1, the process of removing the residual silicon at high temperature is cancelled.

The design idea of the invention is as follows:

silicon carbide powder and resin with high carbon yield are mixed to prepare slurry. Selecting an aluminum foil with proper thickness, cutting the aluminum foil into required shapes and sizes, uniformly coating slurry on one side or two sides, removing redundant slurry through a limiting scraper to enable the slurry to reach the designed thickness, and semi-curing the slurry by adopting an air cooling and heating mode. And laminating a plurality of single-layer aluminum foils coated with the silicon carbide ceramic slurry to obtain a laminated precursor with a certain thickness. Holes are drilled in the laminate precursor according to a defined pore size and pore spacing distribution. And (3) putting the laminated precursor uniformly distributed with the drilled holes into a heated mould for high-temperature and high-pressure curing.

And carrying out resin pyrolysis on the cured laminated precursor in a vacuum or inert gas protection furnace to obtain a layered carbon skeleton consisting of silicon carbide and pyrolytic carbon. After the reaction sintering process, the carbon in the layered carbon skeleton reacts with gas phase or liquid phase silicon to generate silicon carbide, the silicon carbide is combined with original silicon carbide particles in the layered skeleton, and unreacted residual silicon in the interlayer gap is removed by a high-temperature silicon removal method, so that the compact layered silicon carbide ceramic is obtained.

The invention has the following advantages and beneficial effects:

1. the laminated ceramic has high density, uniform microstructure and less residual silicon

The invention adopts a method for curing the layered ceramic precursor by hot pressing, which not only obviously improves the initial density of the layered ceramic precursor, but also eliminates the problem of uneven microstructure formed in the coating process. The adoption of hot-pressing solidifying measures can keep the compactness of the ceramic above 99 percent, reduce the residual silicon content below 10 percent (generally below 5 percent) and ensure that the microstructure is quite uniform, and the hot-pressing solidifying measures are shown in figures 1(a) to (b) and figures 2(a) to (b).

2. Simple process and suitability for batch production

The process for coating and hanging the silicon carbide slurry on the surface of the aluminum foil is simple, the operability is strong, the aluminum foil is used for industrial packaging, and the method for removing the aluminum foil is simple and mature in technology.

The reactive sintering silicon carbide technology is a technical method which is low in cost and suitable for industrial large-scale production, has the characteristics of low densification temperature, short time, low shrinkage rate and small deformation degree, is suitable for manufacturing large-size and complex-shaped components, is easy to obtain net-size products, and reduces subsequent processing cost.

3. The layered silicon carbide ceramic provides a wide design space for the development of composite materials, and provides a concept of toughening a ceramic structure.

Drawings

FIGS. 1(a) to (b) are structural views of a layered silicon carbide ceramic. Wherein, fig. 1(a) is a schematic perspective view, and fig. 1(b) is a macro topography.

FIGS. 2(a) - (b) are the micro-morphologies of the layered silicon carbide ceramic. Wherein, FIG. 2(a) is a microstructure diagram after polishing, and FIG. 2(b) is a microstructure diagram of a fracture of the silicon carbide ceramic.

FIG. 3 is a macroscopic morphology diagram of the layered silicon carbide ceramic and the aluminum alloy after being compounded.

Detailed Description

In the specific implementation process, the flow of the preparation method of the compact layered silicon carbide ceramic is as follows: preparing silicon carbide ceramic slurry → evenly coating silicon carbide slurry on one side or two sides of the aluminum foil → hot pressing densification → pyrolysis → reaction sintering → high temperature removal of residual silicon. Improving the toughness and the shock resistance of the silicon carbide ceramic is an important direction for the research of the silicon carbide ceramic. The laminated ceramic is a special structural ceramic, and is a multilayer structure which takes flaky silicon carbide as basic units, and the basic units are connected by using discrete silicon carbide ceramic columns in a laminated mode. The lamellar structure gaps of the lamellar silicon carbide ceramic are utilized to fill the ductile phases (such as metal, polymer and the like) into the lamellar structure gaps, so that the transmission path and the propagation mechanism of cracks can be changed, the sensitivity of materials to the cracks is reduced and the toughness of the ceramic is improved when the materials bear impact load.

The present invention will be described in detail below with reference to examples.

Example 1

In this example, the weight ratios were 50%: 25%: 5%: 20 percent of silicon carbide powder with the average particle size of 2 mu m, ammonia phenolic resin, p-toluenesulfonic acid and absolute ethyl alcohol are mixed, ball-milled for 3 hours and filtered to prepare slurry. Cutting an aluminum foil with the thickness of 0.5mm into a required shape and size, uniformly coating slurry on one surface, removing redundant slurry through a limiting scraper to control the thickness of the slurry to be 0.6mm, semi-curing in an oven after air drying at the temperature of 50 ℃ for 10 minutes to obtain the single-layer silicon carbide ceramic precursor. And (3) laminating 30 layers of silicon carbide ceramic precursors, and drilling holes on the laminated precursors according to the determined aperture size phi 4mm and the determined hole spacing 10 mm. And (3) putting the laminated precursor uniformly distributed with the drilled holes into a heated mould for high-temperature and high-pressure curing, wherein the pressure is 12MPa, the temperature is increased to 250 ℃, the temperature increasing speed is 3 ℃, and the temperature is kept for 1 hour for curing to obtain the completely cured precursor filled with the silicon carbide slurry in the drilled holes. And (3) pyrolyzing the precursor under the protection of argon, wherein the heating rate is 2 ℃ per minute, the temperature is increased to 800 ℃, and the temperature is kept for 0.5 hour, so that the layered silicon carbide ceramic precursor carbon skeleton is generated. After pyrolysis, reactive sintering was carried out, the weight ratio of silicon lumps (average size 2mm) to carbon skeleton being 0.5: 1, the reaction temperature is 1800 ℃, the whole process is vacuumized, the heating rate is 10 ℃/min, and the temperature is kept for 1 hour, so that the silicon-rich layered silicon carbide ceramic material is obtained. The laminated silicon carbide ceramic material rich in silicon is placed on graphite paper and is carried out under the vacuum condition, the heating rate is 5 ℃ per minute, the temperature is 1750 ℃, the temperature is kept for 1 hour, and unreacted residual silicon in the interlayer gap is removed, so that the compact laminated silicon carbide ceramic material is obtained. The relative compactness of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is 99%, the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 96% of silicon carbide and 4% of residual silicon in percentage by weight, and the average grain size of the silicon carbide is 2.8 mu m.

Example 2

In this example, the weight ratios were 50%: 20%: 3%: 27 percent of silicon carbide powder with the average particle size of 7 mu m, ammonia phenolic resin, p-toluenesulfonic acid and absolute ethyl alcohol are mixed, ball-milled for 1 hour and filtered to prepare slurry. Cutting an aluminum foil with the thickness of 0.3mm into a required shape and size, uniformly coating slurry on one surface, removing redundant slurry through a limiting scraper to control the thickness of the slurry to be 0.5mm, air-drying, and then semi-curing in an oven at the temperature of 50 ℃ for 10 minutes to obtain the single-layer silicon carbide ceramic precursor. And (3) laminating 30 layers of silicon carbide ceramic precursors, and drilling holes on the laminated precursors according to the determined aperture size phi 4mm and the determined hole spacing 10 mm. And (3) putting the laminated precursor uniformly distributed with the drilled holes into a heated mould for high-temperature and high-pressure curing, wherein the pressure is 20MPa, the temperature is increased to 250 ℃, the temperature increasing speed is 2 ℃, and the temperature is kept for 1 hour for curing to obtain the completely cured precursor filled with the silicon carbide slurry in the drilled holes. And (3) pyrolyzing the precursor under the protection of argon, wherein the heating rate is 2 ℃ per minute, the temperature is increased to 800 ℃, and the temperature is kept for 0.5 hour, so that the layered silicon carbide ceramic precursor carbon skeleton is generated. Putting the carbon skeleton into a sodium hydroxide aqueous solution with the concentration of 30 wt% and the temperature of 90 ℃ for treating for 30min, taking out clear water, washing and drying; reaction sintering is carried out, and the weight ratio of the silicon blocks (with the average size of 15mm) to the carbon skeleton is 0.4: 1, the reaction temperature is 1800 ℃, the heating rate is 10 ℃/min under the protection of argon, and the temperature is kept for 1 hour, so that the silicon-rich layered silicon carbide ceramic material is obtained. And (3) placing the silicon-rich layered silicon carbide ceramic material on a graphite plate, carrying out heat preservation for 1 hour at the temperature rising rate of 5 ℃ per minute and the temperature of 1700 ℃ under the vacuum condition, and removing unreacted residual silicon in the interlayer gaps to obtain the compact layered silicon carbide ceramic material. The relative compactness of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is 99%, the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 95% of silicon carbide and 5% of residual silicon in percentage by weight, and the average grain size of the silicon carbide is 8 microns.

Example 3

In this example, the weight ratios were 45%: 25%: 3%: 27 percent of silicon carbide powder with the average particle size of 2 mu m, ammonia phenolic resin, p-toluenesulfonic acid and absolute ethyl alcohol are mixed, ball-milled for 1 hour and filtered to prepare slurry. Cutting an aluminum foil with the thickness of 0.5mm into a required shape and size, uniformly coating slurry on one surface, removing redundant slurry through a limiting scraper to control the thickness of the slurry to be 0.6mm, semi-curing in an oven after air drying at the temperature of 50 ℃ for 10 minutes to obtain the single-layer silicon carbide ceramic precursor. And (3) laminating 30 layers of silicon carbide ceramic precursors, and drilling holes on the laminated precursors according to the determined aperture size phi 3mm and the determined hole spacing 8 mm. And (3) putting the laminated precursor uniformly distributed with the drilled holes into a heated mould for high-temperature and high-pressure curing, wherein the pressure is 40MPa, the temperature is increased to 200 ℃, the temperature increasing speed is 4 ℃, and the temperature is kept for 1 hour for curing to obtain the completely cured precursor filled with the silicon carbide slurry in the drilled holes. And (3) pyrolyzing the precursor under the protection of argon, wherein the heating rate is 2 ℃ per minute, the temperature is increased to 1000 ℃, and the temperature is kept for 0.5 hour, so that the layered silicon carbide ceramic precursor carbon skeleton is generated. After pyrolysis, reactive sintering was carried out, the weight ratio of silicon lumps (average size 8 mesh) to carbon skeleton being 0.4: 1, the reaction temperature is 1700 ℃, the whole process is vacuumized, the heating rate is 10 ℃/min, and the temperature is kept for 1 hour, so that the silicon-rich layered silicon carbide ceramic material is obtained. And (3) placing the silicon-rich layered silicon carbide ceramic material on planar carbon particles (80-120 meshes) under a vacuum condition, heating at the rate of 5 ℃ per minute and the temperature of 1900 ℃, preserving the heat for 0.5 hour, and removing unreacted residual silicon in the interlayer gap to obtain the compact layered silicon carbide ceramic material. The relative compactness of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is 99%, the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 95% of silicon carbide and 5% of residual silicon in percentage by weight, and the average grain size of the silicon carbide is 2.8 mu m.

Example 4

In this example, the weight ratios were 45%: 30%: 5%: 20 percent of silicon carbide powder with the average particle size of 14 mu m, ammonia phenolic resin, p-toluenesulfonic acid and absolute ethyl alcohol are mixed, ball-milled for 2 hours and filtered to prepare slurry. Cutting an aluminum foil with the thickness of 0.1mm into a required shape and size, uniformly coating slurry on two sides, removing redundant slurry through a limiting scraper to control the thickness of the slurry to be 0.3mm, air-drying, and then semi-curing in an oven at the temperature of 50 ℃ for 10 minutes to obtain the single-layer silicon carbide ceramic precursor. And (3) laminating 30 layers of silicon carbide ceramic precursors, and drilling holes on the laminated precursors according to the determined aperture size phi 2mm and the determined hole spacing 6 mm. And (3) putting the laminated precursor uniformly distributed with the drilled holes into a heated mould for high-temperature and high-pressure curing, wherein the pressure is 30MPa, the temperature is increased to 250 ℃, the temperature increasing speed is 1 ℃, and the temperature is kept for 1 hour for curing to obtain the completely cured precursor filled with the silicon carbide slurry in the drilled holes. And (3) pyrolyzing the precursor under the protection of argon, wherein the heating rate is 2 ℃ per minute, the temperature is increased to 800 ℃, and the temperature is kept for 0.5 hour, so that the layered silicon carbide ceramic precursor carbon skeleton is generated. Putting the carbon skeleton into a hydrochloric acid solution with the concentration of 40 wt% and the temperature of 70 ℃ for treating for 60min, taking out the carbon skeleton, washing with clean water, and drying; reaction sintering is carried out, and the weight ratio of the silicon block (average size of 5mm) to the carbon skeleton is 0.2: 1, the reaction temperature is 1900 ℃, the whole process is vacuumized, the heating rate is 10 ℃/min, and the temperature is kept for 1 hour, so that the compact layered silicon carbide ceramic material is obtained. The relative compactness of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is 99%, the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 94% of silicon carbide and 6% of residual silicon in percentage by weight, and the average grain size of the silicon carbide is 16 microns.

Example 5

In this example, the weight ratios were 45%: 30%: 5%: 20 percent of silicon carbide powder with the average particle size of 3.5 mu m, ammonia phenolic resin, p-toluenesulfonic acid and absolute ethyl alcohol are mixed, ball-milled for 2 hours and filtered to prepare slurry. Cutting an aluminum foil with the thickness of 0.1mm into a required shape and size, uniformly coating slurry on two sides, removing redundant slurry through a limiting scraper to control the thickness of the slurry to be 0.3mm, air-drying, and then semi-curing in an oven at the temperature of 50 ℃ for 10 minutes to obtain the single-layer silicon carbide ceramic precursor. And (3) laminating 30 layers of silicon carbide ceramic precursors, and drilling holes on the laminated precursors according to the determined aperture size phi 2mm and the determined hole spacing 6 mm. And (3) putting the laminated precursor uniformly distributed with the drilled holes into a heated mould for high-temperature and high-pressure curing, wherein the pressure is 30MPa, the temperature is increased to 250 ℃, the temperature increasing speed is 5 ℃, and the temperature is kept for 1 hour for curing to obtain the completely cured precursor filled with the silicon carbide slurry in the drilled holes. And (3) pyrolyzing the precursor under the protection of argon, wherein the heating rate is 2 ℃ per minute, the temperature is increased to 800 ℃, and the temperature is kept for 0.5 hour, so that the layered silicon carbide ceramic precursor carbon skeleton is generated. Reaction sintering is carried out, and the weight ratio of the silicon block (average size of 2mm) to the carbon skeleton is 0.3: 1, the reaction temperature is 1550 ℃, the heating rate is 10 ℃/min under the protection of argon, and the temperature is kept for 1 hour, so that the compact layered silicon carbide ceramic material is obtained. The relative compactness of the silicon carbide ceramic basic unit and the silicon carbide ceramic column is 99%, the silicon carbide ceramic basic unit and the silicon carbide ceramic column respectively comprise 96% of silicon carbide and 4% of residual silicon in percentage by weight, and the average grain size of the silicon carbide is 4 microns.

As shown in fig. 1(a) to (b), as can be seen from the structural diagrams of the layered silicon carbide ceramic, the layered silicon carbide ceramic has a three-layer or more structure in which the lamellar silicon carbide ceramic is used as a basic unit and the basic units are connected by discrete silicon carbide ceramic posts in a laminated manner. Gaps exist among the flaky silicon carbide ceramics, and molten metal (such as aluminum alloy, copper alloy and the like) can be injected into the gaps by an extrusion casting method to obtain the silicon carbide ceramic/metal composite material; and (3) injecting macromolecules (such as silicon rubber, polyurea, resin and the like) into the gap by using an isostatic pressing method to obtain the silicon carbide ceramic/macromolecule composite material.

As shown in fig. 2(a) - (b), it can be seen from the structural diagrams of the layered silicon carbide ceramic that the polished silicon carbide ceramic has a flat surface, a uniform and dense tissue and no obvious pores seen from the micro-morphology (a). The reason is that the hot-pressing densification process is adopted in the preparation process, and under the action of high temperature and high pressure, the resin in the semi-cured silicon carbide coating has certain fluidity, so that gaps among silicon carbide particles can be filled, the porosity in the preform is obviously reduced, and the density is improved. From the microscopic morphology (b), the fracture modes of the silicon carbide ceramic are transgranular fracture and intergranular fracture, and the transgranular fracture is mainly used to show that the combination of the ceramic particles is good, and further show that the silicon carbide ceramic has high compactness.

As shown in FIG. 3, it can be seen from the macroscopic topography after the layered silicon carbide ceramic and the aluminum alloy are compounded, the layered silicon carbide ceramic and the ZL101 aluminum alloy have clear layering, good interface combination, and no defects of loose pores and the like.

The embodiment result shows that the method for preparing the laminated silicon carbide ceramic material by coating ceramic slurry on an aluminum foil serving as a template, hot-press forming and reaction sintering has the advantages that: the process is simple, the interlayer size is controllable, and the layered silicon carbide ceramic can be prepared quickly at low cost. The density of the laminated ceramic can be obviously improved by adopting the technology of hot-pressing the multilayer ceramic preform, and the improvement of the shock resistance of the silicon carbide ceramic by toughening the laminated structure is an effective way for toughening the silicon carbide ceramic and has important practical significance for expanding the application range of the silicon carbide ceramic.