阅读说明：本技术 一种碳陶制动盘的快速制备方法 (Rapid preparation method of carbon-ceramic brake disc ) 是由 朱苏华 颜兵 鲍思权 刘翼君 于 2020-12-30 设计创作，主要内容包括：本发明公开了一种碳陶制动盘的快速制备方法。首先制备变密度碳纤维预制体,接着将预制体加工出制动盘外形,再对其进行CVI增密,最后熔融渗硅制备出碳陶制动盘。本发明在预制体制备过程中,采用变密度的预制体,同时在预制体阶段先进行加工,可以大幅缩短沉积时间,实现碳陶制动盘的快速制备。另外,预制体下层以网胎层为主,密度较低,通过沉积渗硅形成更加致密的陶瓷基体,作为碳陶制动盘的摩擦面,可以提高刹车盘的耐磨性以及抗氧化性能,而预制体中层以及上层采用更高密度的预制体及针刺密度,对刹车盘的散热及整体增强更为有利。本发明制备的碳陶制动盘密度均匀,生产周期缩短、生产成本大幅下降,对推动碳陶制动盘普及应用有重要的意义。(The invention discloses a rapid preparation method of a carbon-ceramic brake disc. Firstly, preparing a variable-density carbon fiber preform, then processing the preform into the shape of a brake disc, carrying out CVI densification on the preform, and finally carrying out fused siliconizing to prepare the carbon ceramic brake disc. According to the invention, in the preparation process of the preform, the variable-density preform is adopted, and meanwhile, the preform is processed at the preform stage, so that the deposition time can be greatly shortened, and the rapid preparation of the carbon-ceramic brake disc is realized. In addition, the lower layer of the prefabricated body is mainly a net tire layer, the density is lower, a more compact ceramic matrix is formed by depositing siliconizing and serves as a friction surface of the carbon-ceramic brake disc, the wear resistance and the oxidation resistance of the brake disc can be improved, and the middle layer and the upper layer of the prefabricated body are made of prefabricated bodies with higher densities and needling densities, so that the heat dissipation and the integral enhancement of the brake disc are facilitated. The carbon-ceramic brake disc prepared by the method disclosed by the invention is uniform in density, short in production period and greatly reduced in production cost, and has important significance in promoting popularization and application of the carbon-ceramic brake disc.)

1. A method for quickly preparing a carbon-ceramic brake disc is characterized by comprising the following steps: the method comprises the following steps:

step 1: preparation of variable density preforms

The prefabricated body is prepared by alternately laminating different combinations of carbon cloth, non-woven cloth and net tire and needling layer by layer, and the variable-density prefabricated body with an integral structure is prepared by controlling needling density and comprises a prefabricated body upper layer; the middle layer of the prefabricated body and the lower layer of the prefabricated body, wherein the number of layers of the carbon cloth and the net tire on the upper layer of the prefabricated body is 4-6: 1, the number of layers of the non-woven cloth and the net tire on the middle layer of the prefabricated body is 3-4: 1; the lower layer of the prefabricated body is a full-net tire;

step 2 processing of variable density preform

Processing the variable-density prefabricated body prepared in the step 1 according to a design drawing of a carbon-ceramic brake disc to obtain a carbon fiber prefabricated body;

and step 3: CVI densification

Carrying out chemical vapor deposition on the brake disc preform obtained in the step 2 to obtain a carbon-carbon preform,

and 4, step 4: melt siliconizing

And (4) carrying out melt siliconizing on the carbon-carbon preform obtained in the step (3) to obtain the carbon-ceramic brake disc.

2. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 1, the density of the carbon cloth is 320-400 g/m²(ii) a The density of the laid fabric is 240-300 g/m²Said net tireThe surface density is 60 to 100g/m²。

3. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 1, the carbon cloth is laid in the following way in the lamination process: in the first mode, the long carbon fibers in two adjacent layers of carbon cloth are laid according to the orientation of 0 degree/90 degrees, and in the second mode and the four adjacent layers of carbon cloth, the long carbon fibers are laid according to the orientation of-45 degrees/0 degrees/45 degrees/90 degrees;

in the step 1, the laid mode of the laid non-woven fabric in the lamination process is as follows: in the first mode, the long carbon fiber orientations in two adjacent layers of the non-woven cloth are laid according to 0 degrees/90 degrees, and in the second mode or four adjacent layers of the non-woven cloth, the long carbon fiber orientations are laid according to-45 degrees/0 degrees/45 degrees/90 degrees.

4. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 1, the overall density of the variable density preform is 0.4-0.45 g/cm³。

5. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 1, the thickness of the upper layer of the prefabricated body is 10-15 mm, the thickness of the middle layer of the prefabricated body is 20-25 mm, and the thickness of the lower layer of the prefabricated body is 10-12 mm.

6. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 1, in the preparation process of the upper layer of the prefabricated body, the needling density is controlled to be 25-30 needles/cm²(ii) a In the preparation process of the middle layer of the prefabricated body, the needling density is controlled to be 25-30 needles/cm²(ii) a In the preparation process of the lower layer of the prefabricated body, the needling density is controlled to be 15-18 needles/cm²。

7. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 1, the density of the upper layer of the prefabricated body is 0.6-0.65 g/cm³The density of the middle layer of the preform is 0.5-0.55 g/cm³The density of the lower layer of the preform is 0.4-0.45 g/cm³。

8. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in step 3, in the chemical vapor deposition process, the carbon source gas is selected from propylene or/and natural gas, and the diluent gas is selected from Ar or/and N₂(ii) a The flow ratio of the carbon source gas to the diluent gas is 1-2: 1;

and in the chemical vapor deposition process, gas is introduced from the lower part of the lower layer of the preform.

9. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1 or 8, wherein the method comprises the following steps:

in the step 3, in the chemical vapor deposition process, the deposition temperature is 920-1050 ℃, the deposition pressure is 3-5 kPa, and the deposition time is 80-120 h;

in the step 3, the density of the obtained carbon-carbon preform is 1.35-1.55 g/cm³。

10. The method for rapidly preparing the carbon-ceramic brake disc as claimed in claim 1, wherein the method comprises the following steps:

in the step 4, the melt siliconizing is carried out in a vacuum atmosphere, the temperature of the melt siliconizing is 1500-1900 ℃, and the time of the melt siliconizing is 1-3 h;

in the step 4, the density of the carbon ceramic brake disc is 2.0-2.5 g/cm³。

Technical Field

The invention relates to a rapid preparation method of a carbon-ceramic brake disc, and belongs to the technical field of preparation of carbon-ceramic composite materials.

Background

The carbon-ceramic composite material has the advantages of low density, high strength, high temperature resistance, stable friction coefficient, small abrasion loss and the like, and is known as a new-generation brake material. Compared with the traditional steel brake disc, the carbon-ceramic composite brake disc has the advantages that the weight is reduced by two thirds, the energy loading level is improved by one time, the service life is improved by 1-2 times, and the carbon-ceramic composite brake disc has wide application prospects in brake systems of high-speed trains, racing cars, high-grade cars, heavy-duty vehicles, special vehicles and the like. However, the carbon ceramic brake disc has a long manufacturing period, large material processing difficulty and expensive carbon fiber preforms, so that the production and manufacturing cost of the carbon ceramic brake disc is high, and the market promotion of the application of the carbon ceramic brake disc is severely limited.

Chinese patent CN108644260B discloses a method for preparing a lightweight integrated brake shaft disc for a high-speed train, which has the densification conditions: the volume ratio of the carbon source gas to the diluent gas is 0.5-2, the pressure in the furnace is 500-5000 Pa, the deposition temperature is 900-1100 ℃, the deposition time is 300-500 h, and the density of the densified sample piece is 1.3-1.6 g/cm³The densification process is time consuming and usually requires two or more depositions to achieve the desired density. Meanwhile, considering that the surface of the semi-finished product needs to be roughly machined in each densification process so as to open the pore channel blocked by the deposited carbon on the surface of the semi-finished product, the efficiency of next deposition is convenient to improve, and therefore the machining time is correspondingly increased.

Disclosure of Invention

Aiming at the problems of long CVI densification period, long processing time consumption, high production cost and the like in the existing production process of the carbon-ceramic brake disc, the invention aims to provide a rapid preparation method of the carbon-ceramic brake disc, wherein the preparation of a variable-density preform is combined with chemical vapor deposition and fused siliconizing, so that the CVI densification process and the mechanical processing process time consumption of the carbon-ceramic brake disc are obviously shortened, and the production cost of the product is greatly reduced.

In order to achieve the purpose, the invention adopts the following technical scheme

The invention relates to a rapid preparation method of a carbon-ceramic brake disc, which comprises the following steps:

step 1: preparation of variable density preforms

The prefabricated body is prepared by alternately laminating different combinations of carbon cloth, non-woven cloth and net tire and needling layer by layer, and the variable-density prefabricated body with an integral structure is prepared by controlling needling density and comprises a prefabricated body upper layer; the middle layer and the lower layer of the prefabricated body, wherein the number of layers of the carbon cloth and the net tire on the upper layer of the prefabricated body is 4-6: 1, and the number of layers of the non-woven cloth and the net tire on the middle layer of the prefabricated body is 3-4: 1; the lower layer of the prefabricated body is a full-net tire;

step 2 processing of variable density preform

Processing the variable-density prefabricated body prepared in the step 1 according to a design drawing of a carbon-ceramic brake disc to obtain a carbon fiber prefabricated body;

and step 3: CVI densification

Carrying out chemical vapor deposition on the brake disc preform obtained in the step 2 to obtain a carbon-carbon preform,

and 4, step 4: melt siliconizing

And (4) carrying out melt siliconizing on the carbon-carbon preform obtained in the step (3) to obtain the carbon-ceramic brake disc.

According to the preparation method disclosed by the invention, in the preparation process of the preform, the variable-density preform is adopted, and meanwhile, the preform is firstly processed in the preform stage, so that the diffusion path of gas deposition in the later CVI densification process is shortened, the deposition time can be greatly shortened, and the rapid preparation of the carbon-ceramic brake disc is realized. In the preparation process of the variable density body, the lower layer of the prefabricated body is prepared by laminating a full mesh tire and needling layer by layer, so that the density is lower, a more compact ceramic matrix is formed by depositing siliconizing at the later stage and is applied as a friction surface of a carbon ceramic brake disc, the wear resistance and the oxidation resistance of the brake disc can be improved, the middle layer of the prefabricated body is prepared by laminating a non-woven fabric and a mesh tire and needling layer by layer, the upper layer of the prefabricated body is prepared by laminating a carbon fabric and a mesh tire and needling layer by layer, the density is higher, the layers are increased layer by layer, and the heat dissipation and the integral enhancement of the brake disc are more favorable.

Preferably, in step 1, the carbon fiber used in the variable density preform is of T700 grade. In the actual operation process, Dongli T700-12K or other models with the same grade are adopted

Preferably, in the step 1, the density of the carbon cloth is 320-400 g/m²。

Preferably, in the step 1, the density of the non-woven fabric is 240-300 g/m²。

Preferably, in the step 1, the density of the tread surface is 60-100 g/m²。

Preferably, in step 1, the carbon cloth is laid in the following manner in the lamination process: in the first mode, the long carbon fibers in two adjacent layers of carbon cloth are laid according to the orientation of 0 degree/90 degrees, and the long carbon fibers in two adjacent layers of carbon cloth and four adjacent layers of carbon cloth are laid according to the orientation of minus 45 degrees/0 degrees/45 degrees/90 degrees.

Preferably, in step 1, the laid-up manner of the non-woven fabric in the lamination process is as follows: in the first mode, the long carbon fiber orientations in two adjacent layers of the non-woven cloth are laid according to 0 degrees/90 degrees, and in the second mode or four adjacent layers of the non-woven cloth, the long carbon fiber orientations are laid according to-45 degrees/0 degrees/45 degrees/90 degrees.

Preferably, in the step 1, the overall density of the variable density preform is 0.4-0.45 g/cm³。

In the preferable scheme, in the step 1, the thickness of the upper layer of the prefabricated body is 10-15 mm, the thickness of the middle layer of the prefabricated body is 20-25 mm, and the thickness of the lower layer of the prefabricated body is 10-12 mm.

The inventors have found that by using the above thickness ranges for the layers of the preform, the properties of the final material are optimized.

Preferably, in the step 1, the needling density is controlled to be 25-30 needles/cm in the preparation process of the upper layer of the preform²。

Preferably, in the step 1, the needling density is controlled to be 25-30 needles/cm in the preparation process of the middle layer of the preform²。

Preferably, in the step 1, in the preparation process of the lower layer of the preform, the needling density is controlled to be 15-18 needles/cm²。

Preferably, in the step 1, the density of the upper layer of the preform is 0.6-0.65 g/cm³The density of the middle layer of the preform is 0.5-0.55 g/cm³The density of the lower layer of the preform is 0.4-0.45 g/cm³. The inventor finds that the density of each layer of the prefabricated body is controlled within the gradient range, so that the deposition efficiency is highest, and the performance of the finally prepared carbon ceramic brake disc is optimal.

Preferably, in step 3, during the chemical vapor deposition process, the carbon source gas is selected from propylene or/and natural gas, and the diluent gas is selected from Ar or/and N₂(ii) a The flow ratio of the carbon source gas to the diluent gas is 1-2: 1.

Preferably, in the chemical vapor deposition process, gas is introduced from the lower part of the lower layer of the preform.

In the invention, the lower layer of the preform is mainly the mesh layer, the density is low, the pores are more, and the gas is introduced from the lower layer of the preform, so that the deposition time can be further shortened.

In the preferable scheme, in the step 3, in the chemical vapor deposition process, the deposition temperature is 920-1050 ℃, the deposition pressure is 3-5 kPa, and the deposition time is 80-120 h.

In the actual operation process, after chemical vapor deposition, the rest of the deposited sample piece except the end face size needs to be processed to the finished size of the brake disc.

Preferably, in the step 3, the density of the obtained carbon-carbon preform is 1.35-1.55 g/cm³。

In a preferable scheme, in the step 4, the melt siliconizing is carried out in a vacuum atmosphere, the temperature of the melt siliconizing is 1500-1900 ℃, and the time of the melt siliconizing is 1-3 hours.

In the preferable scheme, in the step 4, the density of the carbon ceramic brake disc is 2.0-2.5 g/cm³

In the actual operation process, the brake disc after the melting siliconizing is subjected to end face fine grinding to obtain a finished carbon ceramic brake disc product.

Principles and advantages

According to the preparation method, the variable-density preform is adopted in the preparation process of the preform, gas is introduced from the lower part of the lower layer of the preform in the chemical vapor deposition process, and meanwhile, the gas is firstly processed in the preform stage, so that the diffusion path of gas deposition in the later CVI densification process is shortened, the deposition time can be greatly shortened, and the deposition time is shortened by 50-70 hours compared with the prior art. The carbon-ceramic brake disc can be rapidly prepared. In addition, in the invention, the lower layer of the preform is mainly provided with the mesh layer, the density is lower, a more compact ceramic matrix is formed by depositing siliconizing at the later stage and is applied as a friction surface of the carbon-ceramic brake disc, the wear resistance and the oxidation resistance of the brake disc can be improved, and the middle layer and the upper layer of the preform adopt the preform with higher density and the needling density, so that the heat dissipation and the integral enhancement of the brake disc are more favorable.

The carbon-ceramic brake disc prepared by the method disclosed by the invention is uniform in product density, the production period of the carbon-ceramic brake disc is obviously shortened, the production cost is greatly reduced, and the carbon-ceramic brake disc has an important significance in promoting the popularization and application of the carbon-ceramic brake disc.

Drawings

FIG. 1 is a schematic view of a production process of a carbon ceramic brake disc,

FIG. 2 is a schematic view of a variable density preform structure,

FIG. 3 is a diagram of a processed variable density preform.

The invention is further described with reference to the following figures and detailed description.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

The invention relates to a rapid preparation method of a carbon-ceramic brake disc, which comprises the following specific preparation steps:

in the following examples, the carbon cloth used had an areal density of 350g/m²The density of the laid fabric is 280g/m²The density of the net tread is 80g/m²。

Example 1

Step 1: preparation of variable density preforms

The variable-density prefabricated body is arranged on the upper layer of the prefabricated body; the prefabricated body middle level, prefabricated body lower floor, wherein prefabricated body upper strata is by carbon cloth and the alternating stromatolite of net child and layer by layer acupuncture preparation, carbon cloth: the net core is 4:1, and the needling density is 25 needles/cm²The thickness is 10mm, wherein the long carbon fiber laying mode of carbon cloth is: 0 °/90 °

The middle layer of the prefabricated body is prepared by alternately laminating a non-woven fabric and a net tire and needling layer by layer, wherein the non-woven fabric comprises the following components in percentage by layer: the net core is 3:1, and the needling density is 25 needles/cm²The thickness is 25mm, wherein the long carbon fiber laying mode of carbon cloth is: -45 °/0 °/45 °/90 °/c

The lower layer of the prefabricated body is prepared by laminating full-mesh tires and needling layer by layer, and the needling density is 15g/cm²(ii) a The thickness is 10mm, and finally the carbon fiber preform with the integral structure is obtained, and the density of the preform is 0.45g/cm³。

Step 2: processing of preforms

According to the drawing of the brake disc, a ring with the outer diameter of 420mm, the inner diameter of 200mm and the total thickness of 45mm is processed on the variable-density prefabricated body, then structures such as brake disc reinforcing ribs are processed in the lower-layer structure unit, and the processed prefabricated body is shown in figure 2.

And step 3: CVI densification and processing

Placing the processed preform in a chemical vapor deposition furnace, and introducing a propylene and argon mixed gas (propylene: argon is 1:1), wherein the gas introduction mode is as follows: introducing the gas from the bottom of the lower layer of the preform, wherein the deposition temperature is 920 ℃, the deposition pressure is 3-5 kPa, the deposition time is 80h, and the density of the deposited sample is 1.37g/cm³(ii) a And processing the rest of the deposited sample except the end face size to the finished size of the brake disc.

And 4, step 4: melt siliconizing

Putting the processed brake disc sample piece into a crucible containing silicon powder, then putting the brake disc sample piece into a high-temperature furnace for melt siliconizing, wherein the melt siliconizing temperature is 1900 ℃, the treatment time is 1h in a vacuum atmosphere, and the density of a product after melt siliconizing is 2.15g/cm³。

Step five: end face finish grinding

And (4) finely grinding the end face of the brake disc subjected to the molten siliconizing to obtain a finished carbon ceramic brake disc product.

Comparative example 1:

a method for rapidly manufacturing a carbon ceramic brake disc, the specific manufacturing steps are as described in example 1, except that the carbon fiber preform in comparative example 1 is directly manufactured by alternately laminating layers of a non-woven fabric and a mesh fabric and needling layer by layer, wherein the long carbon fibers are laid by adopting the following steps: -45 °/0 °/45 °/90 °, the density of the carbon fiber preform obtained was 0.45g/cm³The thickness was 45mm, and other process preparation conditions were the same as in example 1.

Example 2:

step 1: preparation of variable density preforms

The variable-density prefabricated body is arranged on the upper layer of the prefabricated body; the prefabricated body middle level, prefabricated body lower floor, wherein prefabricated body upper strata is by carbon cloth and the alternating stromatolite of net child and layer by layer acupuncture preparation, carbon cloth: the net core is 6:1, and the needling density is 30 needles/cm²The thickness is 15mm, wherein the laying mode of carbon cloth is: -45 °/0 °/45 °/90 °/c

The middle layer of the prefabricated body is prepared by alternately laminating a non-woven fabric and a net tire and needling layer by layer, wherein the non-woven fabric comprises the following components in percentage by layer: the net core is 4:1, and the needling density is 30 needles/cm²The thickness is 20mm, wherein the laying mode of carbon cloth is: -45 °/0 °/45 °/90 °/c

The lower layer of the prefabricated body is prepared by laminating full-mesh tires and needling layer by layer, and the needling density is 18 needles/cm²(ii) a The thickness is 10mm, and finally the carbon fiber preform with the integral structure is obtained, and the density of the preform is 0.50g/cm³。

Step 2: processing of preforms

According to the drawing of the brake disc, the variable-density prefabricated body is processed into a ring with the outer diameter of 400mm, the inner diameter of 180mm and the total thickness of 45mm, and then structures such as a brake disc reinforcing rib are processed in the upper layer structural unit and the lower layer structural unit.

And step 3: CVI densification and processing

Placing the processed prefabricated body in a chemical vapor deposition furnace, and introducing natural gas and N₂Gas mixture (natural gas: N)₂1.5:1), the deposition temperature is 950 ℃, the deposition pressure is 3-5 kPa, the deposition time is 120h, and the density of a sample after deposition is 1.50g/cm³(ii) a And processing the rest of the deposited sample except the end face size to the finished size of the brake disc.

And 4, step 4: melt siliconizing

Putting the processed brake disc sample piece into a crucible containing silicon powder, then putting the brake disc sample piece into a high-temperature furnace for melt siliconizing, wherein the melt siliconizing temperature is 1500 ℃, the vacuum atmosphere is adopted, the treatment time is 3 hours, and the density of a product after melt siliconizing is 2.50g/cm³。。

And 5: end face finish grinding

And (4) performing end face fine grinding on the brake disc subjected to the molten siliconizing to obtain a finished carbon-ceramic brake disc product.

Example 3:

step 1: preparation of variable density preforms

The variable-density prefabricated body is arranged on the upper layer of the prefabricated body; the prefabricated body middle level, prefabricated body lower floor, wherein prefabricated body upper strata is by carbon cloth and the alternating stromatolite of net child and layer by layer acupuncture preparation, carbon cloth: the net tire is 5:1, and the needling density is 27 needles/cm²The thickness is 13mm, wherein the laying mode of carbon cloth is: -45 °/0 °/45 °/90 °/c

The middle layer of the prefabricated body is prepared by alternately laminating a non-woven fabric and a net tire and needling layer by layer, wherein the non-woven fabric comprises the following components in percentage by layer: the net tire is 3.5:1, and the needling density is 27 needles/cm²The thickness is 20mm, wherein the laying mode of carbon cloth is: 0 °/90 °

The lower layer of the prefabricated body is prepared by laminating full-mesh tires and needling layer by layer, and the needling density is 17 needles/cm²(ii) a The thickness is 12mm, and finally the carbon fiber preform with the integral structure is obtained, and the density of the preform is 0.47g/cm³。

Step 2: processing of preforms

According to the drawing of the brake disc, the variable-density prefabricated body is processed into a ring with the outer diameter of 400mm, the inner diameter of 180mm and the total thickness of 45mm, and then structures such as a brake disc reinforcing rib are processed in the upper layer structural unit and the lower layer structural unit.

And step 3: CVI densification and processing

Placing the processed preform in a chemical vapor deposition furnace, introducing natural gas, propylene and argon mixed gas (the mixed gas of the natural gas and the propylene: argon is 1.2:1), depositing at 1020 ℃ and depositing pressureThe force is 3-5 kPa, the deposition time is 100h, and the density of the deposited sample is 1.44g/cm³(ii) a And processing the rest of the deposited sample except the end face size to the finished size of the brake disc.

And 4, step 4: melt siliconizing

Putting the processed brake disc sample piece into a crucible containing silicon powder, and then putting the brake disc sample piece into a high-temperature furnace for melt siliconizing at the melt siliconizing temperature of 1700 ℃, under a vacuum atmosphere, for 1.5h, wherein the density of the product after melt siliconizing is 2.42g/cm³。。

And 5: end face finish grinding

And (4) performing end face fine grinding on the brake disc subjected to the molten siliconizing to obtain a finished carbon-ceramic brake disc product.

All of the above examples and comparative examples were tested for performance, including: performing density test on the semi-finished product after the CVI process is finished; the dynamic friction coefficient of the carbon-ceramic brake disc; in the carbon-ceramic brake disc obtained after completion of the melt siliconizing, the open porosity of the full-mesh bed portion (for comparative example 1, the open porosity in table 1 indicates the overall open porosity because the full-mesh bed portion is omitted), and the finally obtained test data are as shown in table 1:

TABLE 1

	Example 1	Comparative example 1	Example 2	Example 3
					Density after CVI (g/cm)3)	1.38	1.02	1.50	1.44
Coefficient of dynamic friction (Whole net tyre layer)	0.43	0.23	0.50	0.46
					Open area ratio (full net tyre part)	1.0％	12.3％	0.5％	0.7％

From table 1 it can be seen that the density achieved by example 1 is significantly higher than in comparative example 1 at the same CVI deposition time, i.e.: the carbon fiber preform designed in a variable density mode can reach the required density before melt siliconizing in shorter CVI deposition time, thereby greatly shortening the production time of the carbon ceramic brake disc and reducing the production cost; from the open pore ratio in table 1, it can be found that the carbon ceramic material prepared from the carbon fiber preform designed in the "variable density" manner has a much lower open pore ratio than the carbon ceramic material prepared from the ordinary carbon fiber preform, and therefore, it is certain that the carbon ceramic material prepared from the "variable density" carbon fiber preform has a higher compactness of the surface of the full-mesh tire layer than the "ordinary carbon fiber preform", and the higher compactness, the better wear resistance, and therefore, the better wear resistance is exhibited. In addition, from the test result of the dynamic friction coefficient, the dynamic friction coefficient value of the carbon ceramic material prepared by the variable-density carbon fiber preform is higher than that of the common carbon ceramic material, and the main reason is that the density of the surface of the full-mesh bed layer of the carbon ceramic material prepared by the variable-density carbon fiber preform is higher, the content of SiC formed by the full-mesh bed layer is relatively higher, and the dynamic friction coefficient can be improved to a certain extent by taking SiC as a friction-increasing hard phase. Therefore, the rapid preparation method of the carbon-ceramic brake disc provided by the invention can obviously improve the frictional wear performance of the existing common carbon-ceramic material while reducing the production cost and improving the product processing efficiency.