A method for preparing a carbon-ceramic brake disc and a carbon-ceramic brake disc

Abstract

The present application relates to the technical field of brake discs, and specifically discloses a method for preparing a carbon-ceramic brake disc and a carbon-ceramic brake disc. The method for preparing a carbon-ceramic brake disc provided in the present application comprises the following steps: preparing a mixture: weighing the components according to the following weight parts: 10-20 parts of boron nitride, 15-20 parts of 75-100% ethanol, and 60-75 parts of silicon particles, mixing the components evenly, and drying to obtain a mixture; melt siliconizing: placing the mixture at the bottom of a crucible, then placing a C / C preform on the mixture, placing the crucible in a high-temperature furnace for melt siliconizing, and cooling to obtain a carbon-ceramic brake disc. The method for preparing a carbon-ceramic brake pad provided in the present application has the advantages of high production efficiency and good surface structural integrity of the obtained carbon-ceramic brake pad, and has good application prospects.

Description

Technical Field

[0001] The present application relates to the technical field of brake discs, and in particular to a method for preparing a carbon-ceramic brake disc and a carbon-ceramic brake disc. Background Art

[0002] With the rapid development of the modern automotive industry, vehicle performance is becoming increasingly advanced, placing higher demands on braking performance. To meet these demands, brake materials must be lightweight, resistant to high-temperature oxidation, corrosion, and thermal fade. Carbon-ceramic composites are considered an ideal material for next-generation automotive brake discs due to their excellent friction properties, low density (approximately one-third that of conventional cast iron), superior corrosion resistance, and thermal fade resistance.

[0003] In the production of carbon-ceramic brake discs, the most common siliconizing process is liquid phase infiltration (LSI). The existing LSI process typically places a carbon / carbon preform block under the brake disc as support and a silicon absorption channel. An appropriate amount of silicon powder is then added to a crucible from the inner ring of the disc, and melt siliconized in a high-temperature furnace. However, this process can easily lead to a large amount of residual silicon material accumulating at the bottom of the carbon-ceramic brake disc after siliconizing, causing it to adhere to the disc. Furthermore, the C / C preform block can also adhere to the disc during siliconizing, making cleaning more difficult and prone to material shortages or dropouts, impacting product quality and production efficiency. Summary of the Invention

[0004] In order to solve the problem of residual silicon material and adhesion of C / C preform pads to carbon-ceramic brake discs in the existing siliconizing process, the present application provides a method for preparing a carbon-ceramic brake disc and a carbon-ceramic brake disc.

[0005] In a first aspect, the present application provides a method for preparing a carbon-ceramic brake disc, using the following technical solution:

[0006] A method for preparing a carbon-ceramic brake disc comprises the following steps:

[0007] Prepare a mixture: weigh the following components in parts by weight: 10-20 parts of boron nitride, 15-20 parts of 75-100% ethanol, and 60-75 parts of silicon particles, mix the components evenly, and dry them to obtain a mixture;

[0008] Melt siliconization: the mixture is placed at the bottom of a crucible, and then a C / C preform is placed on the mixture. The crucible is then placed in a high-temperature furnace for melt siliconization. After cooling, a carbon ceramic brake disc is obtained.

[0009] This application provides a method for preparing carbon-ceramic brake discs. By using a specific mixture for melt siliconization, this method effectively addresses the problem of residual silicon material adhering to the carbon-ceramic brake disc during traditional melt siliconization, thereby improving the quality and production efficiency of carbon-ceramic brake discs. Specifically, this application pre-places a mixture of boron nitride, ethanol, and silicon particles at the bottom of a crucible, using this mixture as a support layer for a carbon-ceramic preform. During the melt siliconization process, the silicon particles in the mixture gradually permeate the C / C preform, while a boron nitride layer gradually forms on the surface of the mixture. Boron nitride has excellent high-temperature stability and chemical corrosion resistance. This boron nitride layer effectively isolates the residual silicon material from the brake disc, preventing residual silicon from adhering to the carbon-ceramic brake disc. The evaporation of ethanol during the drying process forms a uniformly distributed microporous structure, which helps improve the efficiency of silicon material exudation and optimizes the surface quality and structural integrity of the carbon-ceramic brake disc. In summary, the present application can significantly improve the production efficiency of carbon-ceramic brake discs while greatly improving the quality of carbon-ceramic brake discs by using a specific mixture for melt siliconization.

[0010] In this application, when the amount of boron nitride is too small, silicon nodules and sticky materials will appear on the surface of the carbon-ceramic brake disc produced. When the amount of boron nitride is too large, the siliconization of the carbon-ceramic brake disc will be unsaturated, and the overall performance will deteriorate. When the amount of ethanol is too small, the uniformity of the mixture is poor, resulting in uneven penetration of silicon particles during the melt siliconization process, affecting the siliconization quality of the carbon-ceramic brake disc. When the amount of ethanol is too large, the mixture is not easy to dry, resulting in poor encapsulation of silicon particles by boron nitride, affecting the siliconization quality of the carbon-ceramic brake disc. Therefore, through experimental research, this application found that by controlling the addition amount of each component in the mixture within the above range, the siliconization quality of the brake disc is good, and the quality of the obtained carbon-ceramic brake disc is excellent.

[0011] In some embodiments, the weight portion of the boron nitride may be 10-15 parts or 15-20 parts.

[0012] In a specific embodiment, the weight portion of the boron nitride may be 10 parts, 15 parts or 20 parts.

[0013] In a specific embodiment, the weight portion of the ethanol may be 15 parts or 20 parts.

[0014] In some embodiments, the silicon particles may be present in an amount of 60-65 parts, 60-70 parts, 60-75 parts, 65-70 parts, 65-75 parts, or 70-75 parts by weight.

[0015] In a specific embodiment, the weight of the silicon particles may be 60 parts, 65 parts, 70 parts or 75 parts.

[0016] Optionally, the drying temperature is 75-85° C. and the drying time is 30±5 min.

[0017] Optionally, the melt siliconizing is carried out according to the following procedure:

[0018] The first heating stage: heating to 1400-1450℃ at a heating rate of 4-5℃ / min, and keeping warm;

[0019] The second heating stage: heating to 1650-1700℃ at a heating rate of 2-3℃ / min and keeping warm.

[0020] Optionally, the holding time of the first heating stage is 60-80 minutes, and the holding time of the second heating stage is 120-150 minutes.

[0021] Optionally, during the melt siliconizing process, the vacuum degree in the furnace is always maintained in the range of 200 to 300 Pa.

[0022] Optionally, the purity of the silicon particles is ≥99.9%, and the particle size is 1-3 mm; the density of the C / C preform is 1.1-1.5 g / cm 3 .

[0023] Optionally, the cooling is performed according to the following procedure:

[0024] The first cooling stage: keep the cooling rate no more than 2℃ / min and cool to 1000℃;

[0025] The second cooling stage: nitrogen is filled into the high-temperature furnace to maintain the pressure in the furnace at 95-100 kPa until it drops to room temperature and then the furnace is opened to obtain the carbon ceramic brake disc.

[0026] In a second aspect, the present application provides a carbon-ceramic brake disc, which is manufactured using the aforementioned method for preparing a carbon-ceramic brake disc.

[0027] In the present application, the carbon ceramic brake disc prepared by the preparation method of the carbon ceramic brake disc has no sticky material or adhesion on the bottom of the brake disc after melt siliconization, and the surface is silvery and has no color difference.

[0028] In summary, this application has the following beneficial effects:

[0029] In the present application, a mixture of boron nitride, ethanol and silicon particles is used to melt-siliconize a C / C preform, which can effectively prevent the residual silicon material after siliconizing from adhering to the carbon-ceramic brake disc, reduce the subsequent cleaning process, and reduce the risk of material shortage / dropping during cleaning, thereby greatly improving the production efficiency and surface structural integrity of the carbon-ceramic brake disc. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1Schematic diagram of the structure before melt siliconization; 1-mixture; 2-C / C preform; 3-crucible;

[0031] Figure 2 Schematic diagram of the structure after melt siliconization; 4-residual silicon and boron nitride; 5-boron nitride layer; 6-carbon ceramic brake disc;

[0032] Figure 3 is a bottom photograph of the carbon-ceramic brake pad obtained in Example 2;

[0033] Figure 4 This is a photo of the bottom of the carbon-ceramic brake pad obtained in Comparative Example 3. DETAILED DESCRIPTION

[0034] The present application provides a method for preparing a carbon-ceramic brake disc, comprising the following steps:

[0035] (1) Preparing a mixture: Weigh the following components in parts by weight: 10-20 parts of boron nitride, 15-20 parts of 75-100% ethanol, and 60-75 parts of silicon particles, mix the components evenly, and dry them at 75-85°C for 30±5 minutes to obtain a mixture;

[0036] (2) Melt siliconization: Place the mixture on the bottom of a crucible and scrape it flat; then place the C / C preform on the mixture and lightly compact it to ensure that the plate surface is in full contact with the mixture. Place the crucible in a high-temperature furnace, evacuate the furnace to the ultimate vacuum, and then perform melt siliconization according to the following procedure:

[0037] The first heating stage: heating to 1400-1450℃ at a heating rate of 4-5℃ / min, and keeping at the above temperature for 60-80min;

[0038] The second heating stage: heating to 1650-1700℃ at a heating rate of 2-3℃ / min, and keeping at the above temperature for 120-150min;

[0039] The vacuum degree in the furnace is maintained at 200-300 Pa during the entire heating / insulation process;

[0040] (3) Cooling: After the heat preservation is completed, start cooling according to the following procedures:

[0041] The first cooling stage: keep the cooling rate no more than 2℃ / min and cool to 1000℃;

[0042] The second cooling stage: nitrogen is filled into the high-temperature furnace to maintain a slightly positive pressure (95-100 kPa, maintained by adding nitrogen during the cooling process) until it drops to room temperature and then the furnace is opened to obtain a carbon ceramic brake disc.

[0043] In this application, the C / C preform is a porous material containing carbon fibers and deposited carbon formed by needling carbon fibers and then depositing them at high temperature, with a density of 0.4 to 0.6 g / cm 3 The chemical composition of boron nitride is 43.6% boron + 56.4% nitrogen, with a density of 2.26g / cm 3 , melting point 3000°C; the purity of silicon particles is ≥99.9%, and the particle size is 1-3 mm; the crucible is a graphite crucible; the raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.

[0044] The present application is further described in detail below in conjunction with preparation examples, embodiments, performance testing experiments and accompanying drawings.

[0045] Preparation Examples 1-7

[0046] Preparation Examples 1-7 each provide a mixed material.

[0047] The difference between the above preparation examples is that the addition amount of each component in the mixture is shown in Table 1 below.

[0048] The preparation method of the mixed material provided in Preparation Example 1-7 is as follows: weigh the components according to the weight parts shown in Table 1, mix the components evenly, and dry them at 80° C. for 30 minutes to obtain the mixed material.

[0049] Comparative Preparation Examples 1-4

[0050] Comparative Preparation Examples 1-4 each provide a mixed material.

[0051] The difference between the above preparation example and preparation example 2 is that the addition amount of each component in the mixture is shown in Table 1 below.

[0052] Table 1 Addition amount of each component in the mixture provided by Preparation Examples 1-7 and Comparative Preparation Examples 1-4

[0053]

[0054] Examples 1-7

[0055] Examples 1-7 respectively provide a method for preparing a carbon-ceramic brake disc.

[0056] The difference between the above embodiments is that the mixed materials used in the carbon ceramic preparation method are respectively derived from Preparation Examples 1-7.

[0057] The method for preparing the carbon-ceramic brake disc provided in Examples 1-7 comprises the following steps:

[0058] (1) Prepare the mixture: proceed according to Preparation Example 1-7.

[0059] (2) Melt siliconization: Place the mixture on the bottom of a crucible and scrape it flat; then place the C / C preform on the mixture and lightly compact it to ensure that the plate surface is in full contact with the mixture. Place the crucible in a high-temperature furnace, evacuate the furnace to the ultimate vacuum, and then perform melt siliconization according to the following procedure:

[0060] The first heating stage: heating to 1400℃ at a heating rate of 4℃ / min and keeping at the above temperature for 60min;

[0061] The second heating stage: heating to 1700℃ at a heating rate of 2.5℃ / min, and keeping at the above temperature for 120-150min; the vacuum degree in the furnace is maintained at 250Pa during the whole heating / keeping process.

[0062] (3) Cooling: After the heat preservation is completed, start cooling according to the following procedures:

[0063] The first cooling stage: maintain the cooling rate at 1.5℃ / min and cool down to 1000℃;

[0064] The second cooling stage: nitrogen is filled into the high-temperature furnace to maintain a slightly positive pressure (100KPa, maintained by adding nitrogen during the cooling process) until it drops to room temperature and then the furnace is opened to obtain a carbon ceramic brake disc.

[0065] Comparative Examples 1-4

[0066] Comparative Examples 1-4 respectively provide a method for preparing a carbon-ceramic brake disc.

[0067] The difference between the comparative example and Example 2 is that the mixed materials used in the carbon ceramic preparation method are derived from comparative preparation examples 1-4 respectively.

[0068] Comparative Example 5

[0069] Comparative Example 5 provides a method for preparing a carbon-ceramic brake disc.

[0070] The difference between the comparative example and Example 2 is that the mixed material is replaced by silicon particles.

[0071] Performance testing

[0072] Carbon ceramic brake discs were prepared according to the methods provided in Examples 1-7 and Comparative Examples 1-5, and then the presence of silicon nodules and sticking materials on the bottom of the brake discs was observed. Various performance tests were also conducted on the carbon ceramic brake discs. The results are shown in Table 2 below.

[0073] (1) Opening rate: Tested in accordance with the provisions of GB / T 1966-2024;

[0074] (2) Bending strength: Tested in accordance with the provisions of GB / T 6569-2006;

[0075] (3) Tensile strength: Tested in accordance with the provisions of GB / T 33501-2017.

[0076] Table 2 Performance test results of carbon ceramic brake discs obtained in Examples 1-7 and Comparative Examples 1-5

[0077]

[0078]

[0079] According to the test results in Table 2, the carbon-ceramic brake discs obtained in Examples 1-7 of the present application have no silicon nodules or sticking materials on their surfaces; whereas the carbon-ceramic brake discs obtained in Comparative Examples 1 and 3-5 have small or large amounts of silicon nodules and sticking materials. Furthermore, the carbon-ceramic brake discs obtained in Comparative Examples 3-4 have a bending strength of only 125-142 MPa and a tensile strength of only 71-74 MPa. The carbon-ceramic brake disc obtained in Comparative Example 2 has an apparent porosity of up to 15%, a bending strength of only 109 MPa, and a tensile strength of only 67 MPa. Therefore, it is explained that the present application uses boron nitride, ethanol and silicon particles as a mixture to melt siliconize the C / C preform, and the weight proportions of the three are controlled within the following range: 10-20 parts of boron nitride, 15-20 parts of 75%-100% ethanol, and 60-75 parts of silicon particles. Under the premise of ensuring the basic performance of the carbon-ceramic brake disc, it can effectively prevent the residual silicon material after siliconization from adhering to the carbon-ceramic brake disc, so that no silicon nodules remain on the surface of the brake disc, reduce the subsequent cleaning process, and reduce the risk of material shortage / dropping during cleaning, thereby greatly improving the production efficiency and surface structural integrity of the carbon-ceramic brake disc.

[0080] Although the present invention has been described in detail above using general descriptions and specific embodiments, it will be apparent to those skilled in the art that modifications and improvements may be made based on the present invention. Therefore, such modifications and improvements, which do not depart from the spirit of the present invention, are intended to be within the scope of protection claimed herein.

Claims

1. A method for preparing a carbon ceramic brake disc, characterized in that: The following steps are involved: Prepare a mixture: weigh the following components in parts by weight: 10-20 parts of boron nitride, 15-20 parts of 75-100% ethanol, and 60-75 parts of silicon particles, mix the components evenly, and dry them to obtain a mixture; Melt siliconization: placing the mixture at the bottom of a crucible, then placing the C / C preform on the mixture, and then placing the crucible in a high-temperature furnace for melt siliconization. After cooling, a carbon ceramic brake disc is obtained; The melt siliconizing is carried out according to the following procedure: The first heating stage: heating to 1400~1450℃ at a heating rate of 4~5℃ / min, keeping warm for 60-80min; The second heating stage: heat up to 1650~1700℃ at a heating rate of 2-3℃ / min and keep warm for 120-150min.

2. The method for preparing a carbon ceramic brake disc according to claim 1, characterized in that: The drying temperature is 75-85° C. and the drying time is 30±5 min.

3. The method for preparing a carbon ceramic brake disc according to claim 1, characterized in that: During the melt siliconizing process, the vacuum degree in the furnace is always maintained in the range of 200-300 Pa.

4. The method for preparing a carbon ceramic brake disc according to claim 1, characterized in that: The purity of the silicon particles is ≥99.9% and the particle size is 1-3 mm; the density of the C / C preform is 1.1-1.5 g / cm 3 .

5. The method for preparing a carbon-ceramic brake disc according to any one of claims 1 to 4, characterized in that: The cooling is carried out according to the following procedure: The first cooling stage: keep the cooling rate no more than 2℃ / min and cool to 1000℃; The second cooling stage: nitrogen is filled into the high-temperature furnace to maintain the pressure in the furnace at 95-100 kPa until it drops to room temperature and then the furnace is opened to obtain the carbon ceramic brake disc.

6. A carbon ceramic brake disc, characterized in that: The carbon ceramic brake disc is prepared by the preparation method according to any one of claims 1 to 5.

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