Composite slurry, preparation method therefor, and use thereof

Abstract

The present application relates to a composite slurry, a preparation method therefor, and a use thereof. The composite slurry comprises the following components: 5%-10% of silicon particles, 55%-65% of silicon carbide particles, 5%-10% of graphite particles, and 25%-35% of a resin solution, wherein the D50 particle size of the silicon particles is 38 µm-80 µm, the D50 particle size of the silicon particles is less than the D50 particle size of the silicon carbide particles, and the D50 particle size of the graphite particles is less than the D50 particle size of the silicon carbide particles. The components of the composite slurry comprise graphite particles, silicon particles, silicon carbide particles, and a resin solution in specific proportions. By controlling the particle size of the silicon particles, and ensuring that the particle size of the silicon carbide particles is greater than the particle sizes of the silicon particles and the graphite particles, the combined effect of these features enables a repair layer formed from the composite slurry to exhibit strong adhesion to a coated carbon-ceramic brake disc, high consistency, and high density.

Description

Composite slurry, its preparation method and application Technical Field

[0001] This application relates to the field of carbon ceramic brake disc technology, and in particular to a composite slurry, its preparation method and application. Background Technology

[0002] Currently, automotive brake discs are still mainly made of powder metallurgy and gray cast iron. These materials are heavy, have a low melting point, and are prone to deformation. Mid-to-high-end cars and racing vehicles are increasingly using brake discs made of carbon / ceramic composite materials. These discs offer advantages such as low density, high temperature resistance, high strength, good friction performance, and long service life. Carbon / ceramic composite materials mainly consist of carbon, silicon, and silicon carbide. The carbon is primarily composed of carbon fibers and matrix carbon. While these two carbon components remain stable at room temperature, they are easily oxidized at temperatures above 400°C. Prolonged exposure to high temperatures can cause oxidation, leading to grooves or other damage on the surface of carbon / ceramic composite brake discs. To better prevent carbon oxidation, coated carbon-ceramic brake discs have been developed. These discs have a silicon carbide (SiC) coating on their surface, which not only improves oxidation resistance but also enhances friction performance. Currently, the production cost and price of coated carbon-ceramic brake discs are relatively high. If the coating surface of a carbon / ceramic brake disc is damaged and rendered unusable, it would result in significant losses. Therefore, repairing them with a repair agent is essential. Traditional repair agents often result in poor adhesion between the coating and the carbon ceramic brake disc itself.

[0003] Therefore, it is necessary to improve traditional technologies. Summary of the Invention

[0004] Based on this, this application provides a composite slurry with good adhesion to the coated carbon ceramic brake disc body, its preparation method and application.

[0005] The technical solution to the above-mentioned technical problems in this application is as follows.

[0006] This application provides a composite slurry, which, by mass percentage, comprises 5%–10% silicon particles, 55%–65% silicon carbide particles, 5%–10% graphite particles, and 25%–35% resin solution. The silicon particles have a D50 particle size of 38 μm–80 μm, which is smaller than the D50 particle size of the silicon carbide particles, and the graphite particles have a D50 particle size is smaller than the D50 particle size of the silicon carbide particles.

[0007] In some embodiments, the D50 particle size of the graphite particles in the composite slurry is smaller than that of the silicon particles.

[0008] In some embodiments, the ratio of the D50 particle size of the silicon particles to the D50 particle size of the silicon carbide particles in the composite slurry is 0.3 to 0.96:1.

[0009] In some embodiments, the ratio of the D50 particle size of the graphite particles to the D50 particle size of the silicon carbide particles in the composite slurry is 0.05 to 0.5:1.

[0010] In some embodiments, the D50 particle size of the silicon carbide particles in the composite slurry is 40 μm to 150 μm.

[0011] In some embodiments, the graphite particles in the composite slurry have a D50 particle size of 10 μm to 20 μm.

[0012] In some embodiments, the silicon carbide particles in the composite slurry are loaded with silicon particles and graphite particles on their surface.

[0013] In some embodiments, the mass ratio of the graphite particles to the silicon carbide particles in the composite slurry is 1:10 to 13.

[0014] In some embodiments, the solid content of the resin solution in the composite slurry is 70% to 80%.

[0015] In some embodiments, the resin solution in the composite slurry comprises a phenolic resin solution.

[0016] This application provides a method for preparing a composite slurry, comprising the following steps:

[0017] The raw materials are provided according to the above-mentioned composite slurry;

[0018] The silicon particles, silicon carbide particles, graphite particles, and resin solution are mixed to prepare a composite slurry.

[0019] This application provides, on the one hand, the application of the aforementioned composite slurry in repairing coated carbon ceramic brake discs.

[0020] In some embodiments, the application of repair coatings in carbon ceramic brake discs includes the following steps:

[0021] The above-mentioned composite slurry is applied to the area to be repaired on the coated carbon ceramic brake disc body to form a repair layer, thereby obtaining a coated carbon ceramic brake disc with a repair layer.

[0022] The coated carbon-ceramic brake disc with a repair layer is subjected to fused silica infiltration.

[0023] In some embodiments, in the application of repair coatings on carbon-ceramic brake discs, the fused silica infiltration includes the following steps:

[0024] The coated carbon-ceramic brake disc with the repair layer is placed in a silicon infiltration furnace, silicon powder is added, and the silicon powder is melted and infiltrated by capillary force, so that the coated carbon-ceramic brake disc body is connected to the repair layer.

[0025] In some embodiments, the application of repairing coated carbon ceramic brake discs includes, before the step of applying the composite slurry to the area to be repaired on the coated carbon ceramic brake disc body, a step of sequentially cleaning and drying the area to be repaired on the coated carbon ceramic brake disc body.

[0026] In some embodiments, in the application of repairing coated carbon ceramic brake discs, after the step of applying the composite slurry to the area to be repaired on the coated carbon ceramic brake disc body, the method further includes the steps of sequentially curing and polishing the composite slurry applied to the area to be repaired on the coated carbon ceramic brake disc body to form a repair layer.

[0027] In some embodiments, in the application of repair coated carbon ceramic brake discs, after the melt-diffusion step, a step of surface treatment is further included on the coated carbon ceramic brake disc obtained by melt-diffusion.

[0028] Compared with the prior art, the composite slurry of this application has the following beneficial effects:

[0029] The composite slurry of this application includes graphite particles, silicon particles, graphite particles and resin solution in a specific ratio. By controlling the particle size of silicon particles and controlling the particle size of silicon carbide particles to be larger than the particle sizes of silicon particles and graphite particles, the interaction of these features makes the repair layer formed by the composite slurry have better adhesion and higher consistency with the coated carbon ceramic brake disc, and the repair layer has higher density. Detailed Implementation

[0030] The present application will be further described in detail below with reference to the embodiments and examples. It should be understood that these embodiments and examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The purpose of providing these embodiments and examples is to make the disclosure of the present application more thorough and comprehensive.

[0031] It should also be understood that this application can be implemented in many different forms and is not limited to the embodiments and examples described herein. Those skilled in the art can make various alterations or modifications without departing from the spirit of this application, and the resulting equivalent forms also fall within the protection scope of this application. For example, features described or illustrated as part of one embodiment can be combined in a suitable manner in another embodiment to produce new embodiments. Furthermore, numerous specific details are set forth in the following description to provide a fuller understanding of this application; it should be understood that this application can be implemented without one or more of these details.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for descriptive purposes only and is not intended to be limiting of the application.

[0033] Unless otherwise stated or in case of contradiction, the terms or phrases used herein shall have the following meanings:

[0034] In this application, the terms "multiple", "various", "multiple times", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0035] The terms “combinations of,” “any combination of,” and “any combination of” used in this article include all suitable combinations of any two or more of the listed items.

[0036] In this document, the term "suitable" as used in "suitable combination", "suitable method", "any suitable method", etc., refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0037] In this document, terms such as "preferred," "better," "more suitable," and "ideal" are merely descriptions of more effective implementation methods or embodiments, and should be understood not to limit the scope of protection of this application. If multiple "preferred" terms appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "preferred" term shall be independent.

[0038] In this application, terms such as "further," "even further," and "particularly" are used to describe purposes and indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0039] In this application, "optionally," "optionally," and "optional" mean that something is optional, that is, it means that it is selected from either "with" or "without." If there are multiple "optional" entries in a technical solution, unless otherwise specified, and there are no contradictions or mutual constraints, each "optional" entry shall be independent.

[0040] In this application, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on quantity.

[0041] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0042] In this application, when numerical intervals (i.e., numerical ranges) are involved, unless otherwise specified, the distribution of selectable numerical values ​​within the numerical interval is considered continuous, and includes the two endpoints of the numerical interval (i.e., the minimum and maximum values), as well as every numerical value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that numerical interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints, which is equivalent to directly listing every integer. When multiple numerical ranges are provided to describe features or characteristics, these numerical ranges can be merged. In other words, unless otherwise specified, the numerical ranges disclosed herein should be understood to include any and all subranges included therein. The "numerical value" in the numerical interval can be any quantitative value, such as a number, percentage, ratio, etc. The term "numerical interval" can be broadly included to include numerical interval types such as percentage intervals, ratio intervals, and proportion intervals.

[0043] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0044] In this application, the terms "room temperature" or "normal temperature" generally refer to 4℃ to 35℃, for example, 20℃ ± 5℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 10℃ to 30℃. In some embodiments of this application, "room temperature" or "normal temperature" refers to 20℃ to 30℃.

[0045] In this application, if the unit of a data range is only followed by the right endpoint, it indicates that the units of the left and right endpoints are the same. For example, 3~5h means that the units of the left endpoint "3" and the right endpoint "5" are both h (hours).

[0046] All references to documents mentioned in this application are incorporated herein by reference as if each document were individually incorporated by reference. Unless they conflict with the inventive purpose and / or technical solution of this application, all cited documents are incorporated herein by reference in their entirety and for all purposes. When citing documents in this application, the definitions of relevant technical features, terms, nouns, phrases, etc., are also incorporated herein by reference. When citing documents in this application, examples and preferred embodiments of the cited technical features may also be incorporated herein by reference, but only to the extent that they enable the implementation of this application. It should be understood that when the cited content conflicts with the description in this application, this application shall prevail or modifications shall be made adaptably to the description in this application.

[0047] The mass or weight of the relevant components mentioned in the embodiments of this application can refer not only to the specific content of each component, but also to the proportional relationship of mass or weight between the components. Therefore, any scaling up or down of the content of the relevant components according to the embodiments of this application is within the scope disclosed in the embodiments of this application. Specifically, the mass or weight mentioned in the embodiments of this application can be units known in the chemical industry, such as μg, mg, g, and kg.

[0048] The process for repairing uncoated carbon ceramic brake discs uses carbon fiber cloth as a carrier and is repaired through resin bonding, impregnation, carbonization, and silicon infiltration. This production process has a long production cycle, is complicated, and has a high repair cost. Furthermore, the defects in these repaired parts are mainly filled with carbon fiber cloth, which is easily oxidized at temperatures above 400°C. During normal braking, the temperature of the brake disc will be above 400°C, resulting in a short service life.

[0049] One embodiment of this application provides a composite slurry, the components of which include 5% to 10% silicon particles, 55% to 65% silicon carbide particles, 5% to 10% graphite particles, and 25% to 35% resin solution. The D50 particle size of the silicon particles is 38 μm to 80 μm, and the D50 particle size of the silicon particles is smaller than that of the silicon carbide particles, and the D50 particle size of the graphite particles is smaller than that of the silicon carbide particles.

[0050] The composite slurry of this application includes graphite particles, silicon particles, graphite particles and resin solution in a specific ratio. By controlling the particle size of silicon particles and controlling the particle size of silicon carbide particles to be larger than the particle sizes of silicon particles and graphite particles, the interaction of these features makes the repair layer formed by the composite slurry have better adhesion and higher consistency with the coated carbon ceramic brake disc, and the repair layer has higher density.

[0051] Among them, the shrinkage rate of the reaction between graphite and silicon is small, which effectively improves the bonding force between the repair layer formed by the composite slurry and the coated carbon ceramic brake disc, and effectively promotes the density of the repair layer; by controlling the particle size of silicon particles, the pores formed during melting are small, which effectively improves the consistency between the repair layer and the coating of the coated carbon ceramic brake disc, and effectively improves the density of the repair layer.

[0052] Research has found that if graphite particles are replaced with carbon particles, gaps exist between the repair layer formed by the composite slurry and the coating of the carbon-ceramic brake disc, resulting in lower bonding strength between the repair layer and the coating, thus affecting the repair pass rate. Analysis suggests this is due to the greater shrinkage rate of the reaction between carbon particles and silicon particles.

[0053] If the silicon particles are too large, the adhesion between the repair layer and the coated carbon-ceramic brake disc will also weaken. Analysis suggests that during the molten silicon infiltration stage, the silicon melts into a liquid state, and large-particle silicon will form large pores in this area, preventing it from becoming dense. This results in pores forming on the coating surface, thus weakening the adhesion between the repair layer and the coated carbon-ceramic brake disc.

[0054] It is understood that, by mass percentage, the composite slurry contains, but is not limited to, 5%, 6%, 7%, 8%, 9%, and 10% silicon particles; 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, and 75% silicon carbide particles; 5% of graphite particles; and 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, and 35% resin solution.

[0055] It is understood that in the composite slurry, the mass ratio of silicon particles to silicon carbide particles is 1:5.5 to 1:13. Further, the mass ratio of silicon particles to silicon carbide particles includes, but is not limited to, 1:5.5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, and 1:13.

[0056] It is understood that in the composite slurry, the mass ratio of graphite particles to silicon carbide particles is 1:5.5 to 1:13. Further, the mass ratio of graphite particles to silicon carbide particles includes, but is not limited to, 1:5.5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, and 1:13. Optionally, the mass ratio of graphite particles to silicon carbide particles is 1:10 to 1:13.

[0057] In some of these examples, the D50 particle size of the graphite particles in the composite slurry is smaller than that of the silicon particles.

[0058] In some of these examples, the ratio of the D50 particle size of silicon particles to the D50 particle size of silicon carbide particles in the composite slurry is 0.3 to 0.96:1.

[0059] It is understood that the ratio between the D50 particle size of silicon particles and the D50 particle size of silicon carbide particles includes, but is not limited to, 0.3:1, 0.38:1, 0.4:1, 0.5:1, 0.53:1, 0.6:1, 0.7:1, 0.76:1, 0.8:1, 0.9:1, and 0.96:1.

[0060] In some of these examples, the ratio of the D50 particle size of graphite particles to the D50 particle size of silicon carbide particles in the composite slurry is 0.05 to 0.5:1.

[0061] It is understood that the ratio between the D50 particle size of graphite particles and the D50 particle size of silicon carbide particles includes, but is not limited to, 0.05:1, 0.06:1, 0.1:1, 0.15:1, 0.2:1, 0.3:1, 0.4:1, and 0.5:1.

[0062] It is understood that the D50 particle size of silicon particles includes, but is not limited to, 38μm, 40μm, 42μm, 45μm, 48μm, 50μm, 52μm, 55μm, 58μm, 60μm, 62μm, 65μm, 68μm, 70μm, 72μm, 75μm, 78μm, and 80μm; in some examples, it can be any two of these point values ​​as end values ​​within a range, the same below.

[0063] In some of these examples, the D50 particle size of the silicon carbide particles in the composite slurry is 40 μm to 150 μm.

[0064] It is understood that the D50 particle size of silicon carbide particles includes, but is not limited to, 40μm, 42μm, 45μm, 48μm, 50μm, 52μm, 55μm, 58μm, 60μm, 62μm, 65μm, 68μm, 70μm, 72μm, 75μm, 78μm, 80μm, 85μm, 90μm, 95μm, 100μm, 105μm, 110μm, 115μm, 120μm, 125μm, 130μm, 135μm, 140μm, 145μm, and 150μm.

[0065] In some of these examples, the D50 particle size of the graphite particles in the composite slurry is 10 μm to 20 μm.

[0066] It is understood that the D50 particle size of graphite particles includes, but is not limited to, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, and 20μm.

[0067] In some of these examples, the surface of the silicon carbide particles in the composite slurry is loaded with both particles and graphite particles.

[0068] It is understood that at least some silicon particles and graphite particles are loaded on the surface of silicon carbide particles; further, it is understood that some or all silicon particles and graphite particles are loaded on the surface of silicon carbide particles.

[0069] By controlling the particle size of silicon particles, silicon carbide particles, and graphite particles, the particle size difference between the three types of particles is small, and the mixing uniformity is good. This can further improve the bonding strength and consistency between the repair layer formed by the composite slurry and the coated carbon ceramic brake disc body, as well as the density of the repair layer.

[0070] In some of these examples, the solid content of the resin solution in the composite slurry is 70% to 80%.

[0071] Compared to directly using resin as a binder, which requires pressing at high temperatures and pressures, posing a risk of damage to the coated carbon-ceramic brake disc and potentially destroying its coating and internal fiber structure, thus reducing its mechanical properties, this application utilizes a resin solution and controls its solid content to effectively enhance the bonding strength between the repair layer formed by the composite slurry and the coated carbon-ceramic brake disc. This eliminates the need for external pressure, resulting in non-destructive repair. Furthermore, the reaction between the resin carbon formed by the carbonization of the polymer resin and silicon further enhances the bonding strength between the repair layer and the coated carbon-ceramic brake disc.

[0072] It is understood that the solid content of the resin solution includes, but is not limited to, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, and 80%.

[0073] In some of these examples, the resin solution in the composite slurry includes a phenolic resin solution.

[0074] It is understandable that phenolic resin solutions can be cured at room temperature.

[0075] One embodiment of this application provides a method for preparing a composite slurry, comprising the following steps:

[0076] The raw materials are provided according to the above-mentioned composite slurry;

[0077] A composite slurry is prepared by mixing silicon particles, silicon carbide particles, graphite particles and resin solution.

[0078] The low shrinkage rate of the reaction between graphite particles and silicon effectively enhances the bonding strength between the repair layer formed by the composite slurry and the coated carbon-ceramic brake disc, and also effectively promotes the density of the repair layer. By controlling the particle size of silicon particles, the pores formed during melting are smaller, effectively improving the consistency between the repair layer and the coating of the coated carbon-ceramic brake disc, and also effectively improving the density of the repair layer. By controlling the particle size of silicon carbide particles to be larger than that of silicon and graphite particles, the surface of silicon carbide particles is loaded with silicon and graphite particles, which is beneficial for subsequent silicon infiltration reaction, thereby improving the bonding strength and consistency between the repair layer and the coating of the coated carbon-ceramic brake disc, as well as the density of the repair layer.

[0079] In some examples, the method for preparing the composite slurry involves mixing silicon particles, silicon carbide particles, graphite particles, and a resin solution, followed by stirring; further, the stirring equipment is a high-pressure pneumatic stirrer; further, the stirring time is 2 to 3 hours.

[0080] One embodiment of this application provides the application of the above-described composite slurry or the composite slurry prepared by the above-described method in the repair of coated carbon ceramic brake discs.

[0081] In some of these examples, the application of repair coatings in carbon ceramic brake discs includes the following steps:

[0082] The composite slurry or the composite slurry prepared by the above preparation method is applied to the area to be repaired on the coated carbon ceramic brake disc body to form a repair layer, thereby obtaining a coated carbon ceramic brake disc with a repair layer.

[0083] The coated carbon ceramic brake disc with a repair layer is subjected to fused silica infiltration.

[0084] It is understood that another embodiment of this application provides a method for repairing coated carbon ceramic brake discs, including the following steps:

[0085] The composite slurry or the composite slurry prepared by the above preparation method is applied to the area to be repaired on the coated carbon ceramic brake disc body to form a repair layer, thereby obtaining a coated carbon ceramic brake disc with a repair layer.

[0086] The coated carbon ceramic brake disc with a repair layer is subjected to fused silica infiltration.

[0087] In some of these examples, in applications that repair coated carbon-ceramic brake discs, fused silica infiltration includes the following steps:

[0088] The coated carbon-ceramic brake disc with a repair layer is placed in a silicon infiltration furnace, silicon powder is added, and the silicon powder is melted and infiltrated by capillary force, so that the coated carbon-ceramic brake disc body and the repair layer are connected.

[0089] In some of these examples, in applications such as repair coatings on carbon ceramic brake discs, the D50 particle size of the silica powder is 6 mm to 10 mm.

[0090] In some of these examples, in the application of repair coatings on carbon-ceramic brake discs, the temperature of molten silicon infiltration is 1450℃~1500℃, the time is 2h~3h, and the vacuum degree is less than 1kPa.

[0091] It is understandable that after the silicon powder is added and before the silicon powder is melted and infiltrated by capillary force, there is also a step of evacuating and heating the silicon infiltration furnace.

[0092] It is understandable that in the process of placing the carbon ceramic brake disc with the repair layer in the silicon infiltration furnace, the carbon ceramic brake disc with the repair layer is first placed in the graphite tooling, and then the tooling is placed in the silicon infiltration furnace.

[0093] The purpose of using graphite tooling is to prevent silicon absorption.

[0094] In some examples, the application of repairing coated carbon ceramic brake discs includes, prior to the step of applying the composite slurry to the area to be repaired on the coated carbon ceramic brake disc body, a step of sequentially cleaning and drying the area to be repaired on the coated carbon ceramic brake disc body.

[0095] Clean the impurities in the area to be repaired to improve the bonding strength and performance after repair.

[0096] In some of these examples, in applications involving the repair of coated carbon-ceramic brake discs, ultrasonic cleaning is employed. Specifically, the cleaning frequency is 50 kHz, and the cleaning time is 20–30 minutes.

[0097] In some of these examples, the application in repairing coated carbon-ceramic brake discs involves drying in a constant-temperature drying oven. Specifically, the drying temperature is 120°C–130°C, and the drying time is 2–3 hours.

[0098] In some examples, in the application of repairing coated carbon ceramic brake discs, after the step of applying the composite slurry to the area to be repaired on the coated carbon ceramic brake disc body, the steps further include curing and polishing the composite slurry applied to the area to be repaired on the coated carbon ceramic brake disc body in sequence to form a repair layer.

[0099] It is understandable that when phenolic resin solution is used as a binder, it can be cured at room temperature; furthermore, the curing time is 6h to 8h.

[0100] In some examples, in the application of repair coating carbon ceramic brake discs, after the melt-diffusion step, a step of surface treatment is also included on the coated carbon ceramic brake disc obtained by melt-diffusion.

[0101] It is understandable that, in some of these examples, the application of repair coatings in carbon ceramic brake discs includes the following steps:

[0102] Step S1: Clean and dry the areas of the coated carbon ceramic brake disc to be repaired in sequence;

[0103] Step S2: Apply the composite slurry prepared by the above-mentioned composite slurry or the above-mentioned preparation method to the area to be repaired on the coated carbon ceramic brake disc body after drying in step S1. Then, the composite slurry applied to the area to be repaired on the coated carbon ceramic brake disc body is cured and polished in sequence to form a repair layer, thereby obtaining a coated carbon ceramic brake disc with a repair layer.

[0104] Step S3: The coated carbon-ceramic brake disc with the repair layer obtained in step S2 is subjected to melt silicon infiltration;

[0105] Step S4: Perform surface treatment on the coated carbon ceramic brake disc obtained by melt infiltration in step S3.

[0106] The composite slurry prepared by the above-mentioned composite slurry or the above-mentioned preparation method is used to repair the part of the coated carbon ceramic brake disc body to be repaired. The resulting repair layer has strong adhesion and good compatibility with the coated carbon ceramic brake disc body. Moreover, the repair is simple, the cycle is short, it is a non-destructive repair, the repair layer has high uniformity, good process stability, low repair cost, high repair yield, high strength, and excellent friction and wear performance.

[0107] The present application will be described in further detail below with reference to specific embodiments, but the embodiments of the present application are not limited thereto.

[0108] Example 1

[0109] (1) Clean the impurities on the surface of the carbon ceramic brake disc coating to be repaired by ultrasonic water washing, and then dry it; the ultrasonic cleaning time is 20 min and the cleaning frequency is 50 kHz; the drying equipment is a constant temperature drying oven, the temperature is 120℃ and the time is 2 to 3 h.

[0110] (2) The raw materials silicon powder, silicon carbide powder, graphite powder and resin solution are mixed in a mass percentage ratio of 5%:65%:5%:25% and stirred to obtain a uniform repair agent; wherein, the resin solution is a phenolic resin solution with a solid content of 80%; in the repair agent, the D50 particle size of silicon particles is 38μm, the D50 particle size of silicon carbide particles is 50μm and the D50 particle size of graphite particles is 20μm;

[0111] (3) Fill the repair agent into the surface of the carbon ceramic brake disc coating repair area after cleaning in step (1). After the repair agent has completely cured, use sandpaper to smooth the filled area.

[0112] (4) Place the carbon ceramic brake disc after step (3) into a graphite tooling, put silicon particles (particle size 10mm) into the repair area, put the graphite tooling into a high-temperature silicon infiltration furnace, evacuate the furnace and raise the temperature to carry out melt silicon infiltration; the temperature of the high-temperature silicon infiltration furnace is 1450℃, the time is 2h, and the vacuum degree is less than 1kPa.

[0113] (5) The carbon ceramic brake disc after molten silicon infiltration is finely processed and the surface is treated to obtain the repaired coated carbon ceramic brake disc.

[0114] Example 2

[0115] The process is basically the same as in Example 1, except that in step (2), the mass percentages of the raw materials silicon powder, silicon carbide powder, graphite powder and resin solution in the repair agent are 5%:60%:5%:30%.

[0116] Example 3

[0117] The process is basically the same as in Example 1, except that in step (2), the mass percentages of the raw materials silicon powder, silicon carbide powder, graphite powder and resin solution in the repair agent are 10%:55%:5%:25%.

[0118] Example 4

[0119] The process is basically the same as in Example 1, except that in step (2) the D50 particle size of silicon particles is 48 μm, the D50 particle size of silicon carbide particles is 50 μm, and the D50 particle size of graphite particles is 20 μm.

[0120] Example 5

[0121] The process is basically the same as in Example 1, except that in step (2) the D50 particle size of silicon particles is 38 μm, the D50 particle size of silicon carbide particles is 100 μm, and the D50 particle size of graphite particles is 20 μm.

[0122] Example 6

[0123] The process is basically the same as in Example 1, except that in step (2) the D50 particle size of silicon particles is 50 μm, the D50 particle size of silicon carbide particles is 100 μm, and the D50 particle size of graphite particles is 15 μm.

[0124] Example 7

[0125] The process is basically the same as in Example 1, except that in step (2) the particle size of silicon particles is 80 μm, the D50 particle size of silicon carbide particles is 150 μm, and the D50 particle size of graphite particles is 10 μm.

[0126] Comparative Example 1

[0127] The process is basically the same as in Example 1, except that in step (2) of the repair agent, graphite powder is replaced with carbon powder of equal mass, and the D50 particle size of the carbon particles in the prepared repair agent is 20 μm.

[0128] Comparative Example 2

[0129] It is basically the same as Example 1, except that in step (2) the D50 particle size of the silicon particles in the repair agent is 2 mm.

[0130] Comparative Example 3

[0131] The process is basically the same as in Example 1, except that in step (2) the D50 particle size of silicon carbide particles is 15 μm, the D50 particle size of silicon particles is larger than that of silicon carbide particles, and the D50 particle size of graphite particles is larger than that of silicon carbide particles.

[0132] The component parameters of the repair agents used in each embodiment and comparative example are shown in Table 1. "Silicon particles:silicon carbide particles" refers to the ratio between the D50 particle size of silicon particles and the D50 particle size of silicon carbide particles, and "graphite particles:silicon carbide particles" refers to the ratio between the D50 particle size of graphite particles and the D50 particle size of silicon carbide particles.

[0133] Table 1

[0134]

[0135] The performance of the coated carbon-ceramic brake discs repaired in each embodiment and comparative example was tested: the shear strength between the coating and the substrate was tested to characterize the bonding force between the repair coating formed by the repair agent and the coated carbon-ceramic brake disc, and the value was the mean of five samples (GB / T 28889-2012); the coating density was measured, and the standard deviation of different densities with the same proportion of formulation was calculated to characterize the consistency of the repair coating; the density was characterized by measuring the percentage of the repair coating density to the theoretical silicon carbide density (silicon carbide density: 3.21). The results are shown in Table 2.

[0136] Table 2

[0137]

[0138] As can be seen from Table 2, compared with Comparative Examples 1-3, the repair agents prepared in Examples 1-7 have better bonding strength, higher consistency and density.

[0139] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A composite paste, characterized by, The composition, by mass percentage, includes 5%–10% silicon particles, 55%–65% silicon carbide particles, 5%–10% graphite particles, and 25%–35% resin solution. The D50 particle size of the silicon particles is 38 μm–80 μm, which is smaller than that of the silicon carbide particles, and the D50 particle size of the graphite particles is smaller than that of the silicon carbide particles.

2. The composite paste of claim 1, wherein, The D50 particle size of the graphite particles is smaller than that of the silicon particles.

3. The composite paste of claim 1, wherein, The composite slurry satisfies at least one of the following characteristics: (1) The ratio between the D50 particle size of the silicon particles and the D50 particle size of the silicon carbide particles is 0.3 to 0.96:1; (2) The ratio between the D50 particle size of the graphite particles and the D50 particle size of the silicon carbide particles is 0.05 to 0.5:

1.

4. The composite slurry according to any one of claims 1 to 3, wherein The composite slurry satisfies at least one of the following characteristics: (1) The D50 particle size of the silicon carbide particles is 40μm to 150μm; (2) The D50 particle size of the graphite particles is 10μm to 20μm; (3) The surface of the silicon carbide particles is loaded with silicon particles and graphite particles.

5. The composite slurry according to any one of claims 1 to 3, wherein The composite slurry satisfies at least one of the following characteristics: (1) The solid content of the resin solution is 70% to 80%; (2) The resin solution includes a phenolic resin solution; (3) The mass ratio of the graphite particles to the silicon carbide particles is 1:10 to 13.

6. A method of preparing a composite paste, characterized by, Includes the following steps: The raw material is provided according to any one of claims 1 to 5; The silicon particles, silicon carbide particles, graphite particles, and resin solution are mixed to prepare a composite slurry.

7. The application of the composite slurry as described in any one of claims 1 to 5 in the repair of coated carbon ceramic brake discs.

8. Use according to claim 7, wherein the compound is ###0002### Includes the following steps: The composite slurry is applied to the area to be repaired on the coated carbon ceramic brake disc body to form a repair layer, resulting in a coated carbon ceramic brake disc with a repair layer. The coated carbon-ceramic brake disc with a repair layer is subjected to fused silica infiltration.

9. Use according to claim 8, wherein the compound is ###0002### The fused silicon infiltration process includes the following steps: The coated carbon-ceramic brake disc with the repair layer is placed in a silicon infiltration furnace, silicon powder is added, and the silicon powder is melted and infiltrated by capillary force, so that the coated carbon-ceramic brake disc body is connected to the repair layer.

10. Use according to any one of claims 8 to 9, characterized in that, The step satisfies at least one of the following characteristics: (1) Before the step of applying the composite slurry to the repair area of ​​the coated carbon ceramic brake disc body, the repair area of ​​the coated carbon ceramic brake disc body is further cleaned and dried in sequence. (2) After the step of applying the composite slurry to the repaired area of ​​the coated carbon ceramic brake disc body, the method further includes the step of curing and polishing the composite slurry applied to the repaired area of ​​the coated carbon ceramic brake disc body in sequence to form the repair layer. (3) After the melt infiltration step, the method further includes a step of surface treatment of the coated carbon ceramic brake disc obtained by melt infiltration.

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