Ceramic brake disc and preparation method and application thereof

Abstract

The invention relates to a ceramic brake disc which comprises a disc base body, and the disc base body is provided with a first surface and a second surface which are opposite to each other; the disc base body comprises silicon carbide, free silicon, short fiber bundles and long carbon fibers; wherein the long carbon fibers extend from the first surface to the second surface. The through hole is formed in the upper pressing head of the mold, and the blind hole matched with the through hole is formed in the forming surface of the lower pressing head of the mold, so that displacement of the long carbon fibers in the mold pressing process is limited, the long carbon fibers can have good axial orientation in the disc base body, the prepared ceramic brake disc has continuous and uniform vertical carbon fibers, and the service life of the ceramic brake disc is prolonged. The bending strength and the shearing strength of the ceramic brake disc in the Z-direction are effectively improved, so that the mechanical strength and the mechanical property of the ceramic brake disc are remarkably improved, meanwhile, the preparation cost is low, and the preparation process is simple.

Description

Technical Field

[0001] The present invention belongs to the field of ceramic brake discs, and in particular relates to a ceramic brake disc and a preparation method and application thereof. Background Art

[0002] There are two types of carbon ceramic brake discs on the market: one is made of continuous fibers, and the other is made of short fibers. Among them, short fiber brake discs have low cost, simple process, and convenient design of filling matrices of different costs, and have recently become one of the research and development hotspots.

[0003] Currently, most methods use molding to add vertical fibers to brake discs to enhance the mechanical strength and mechanical properties of carbon-ceramic brake discs. However, due to the large amount of compression (compression ratio of 3:1), during this process, the ordinary adding method will cause the vertical fibers to break under pressure, or the carbon fibers tend to be horizontally distributed under pressure, which significantly reduces the bending strength of the prepared product along the Z-direction, resulting in poor mechanical strength and mechanical properties of the prepared product. Summary of the invention

[0004] The purpose of the present invention is to provide a ceramic brake disc and a preparation method and use thereof. The disc matrix of the ceramic brake disc prepared by the present invention has continuous and uniform vertical carbon fibers, and the carbon fibers have good Z-direction orientation, which effectively increases the bending strength and shear strength of the ceramic brake disc along the Z-direction, thereby further improving the mechanical strength and mechanical properties of the ceramic brake disc.

[0005] In order to achieve the above object, the present invention provides a ceramic brake disc in a first aspect, wherein the ceramic brake disc comprises a disc substrate having a first surface and a second surface opposite to each other; the disc substrate comprises silicon carbide, free silicon, short fiber bundles and long carbon fibers;

[0006] Wherein, the carbon fibers extend from the first surface to the second surface.

[0007] Optionally, the angle between the carbon fiber and the thickness direction of the brake disc is within 20°.

[0008] Optionally, the long carbon fiber comprises a long carbon fiber rod or a long carbon fiber bundle;

[0009] Wherein, the distance between two adjacent long carbon fibers is 3 to 30 mm.

[0010] Optionally, the diameter of the long carbon fiber rod is 0.5-5 mm, and the diameter of each of the long carbon fiber bundles is 0.5-2 mm.

[0011] Optionally, the length of the long carbon fiber bundle is 2 to 5 cm.

[0012] Optionally, the length of the short fiber bundle is 0.5 to 1.5 cm, and the diameter of the short fiber bundle is 0.3 to 0.6 mm.

[0013] Optionally, based on the mass of the ceramic brake disc, the mass of silicon carbide in the ceramic brake disc is 45-65wt%, the content of free silicon is 5-12wt%, the content of long carbon fibers is 3-8wt%, and the content of short fiber bundles is 27-42wt%.

[0014] Optionally, the average particle size of the carbon powder is 0.5 to 20 μm.

[0015] Optionally, the density of the ceramic brake disc is 2.0-2.5 g / cm 3 The ceramic brake disc has a bending strength of more than 120 MPa in the direction parallel to the friction surface, a compressive strength of more than 240 MPa, a bending strength of more than 80 MPa in the Z-direction, and a shear strength of more than 12 MPa.

[0016] A second aspect of the present invention provides a method for preparing a ceramic brake disc, wherein the method comprises:

[0017] S1, mixing carbon powder, thermosetting resin monomer, silicon carbide powder, short fiber bundles and solvent, drying, separating agglomerated short fiber bundles, and obtaining a mixture;

[0018] S2, placing the long carbon fiber and the mixed material in a molding cavity of a mold respectively, and performing pressurized curing treatment to obtain a cured embryo;

[0019] S3, sequentially subjecting the solidified embryo to carbonization treatment and liquid phase siliconization;

[0020] Wherein, the mold includes an upper press head and a lower press head; the upper press head is provided with a through hole; the molding surface of the lower press head is provided with a blind hole matching the through hole, and during the pressurized curing process of step S2, the long carbon fiber is limited by the blind hole and the through hole to extend in a direction perpendicular to the disk surface.

[0021] Optionally, the through holes and the blind holes are distributed in an array; the diameters of the through holes and the blind holes are 0.5 to 5 mm, and the hole spacing is 3 to 30 mm; and each of the through holes contains 1 to 5 long carbon fibers.

[0022] Optionally, the ratio of the diameter of the long carbon fiber to the diameter of the blind hole is (0.9-0.97):1.

[0023] Optionally, based on the mass of the mixture, the content of carbon powder in the mixture is 10-30wt%, the content of thermosetting resin monomer is 15-40wt%, the content of silicon carbide powder is 0.1-25wt%, the content of short fiber bundle is 30-60wt%, and the content of solvent is 10-30wt%;

[0024] The length of the short fiber bundle is 0.5 to 1.5 cm, and the diameter of the short fiber bundle is 0.3 to 0.6 mm;

[0025] The thermosetting resin monomer is selected from one or more of phenolic resin, epoxy resin and furan resin; the solvent is selected from one or more of ethanol and tetramethylammonium hydroxide.

[0026] Optionally, the long carbon fiber comprises a long carbon fiber rod or a long carbon fiber bundle; the length of the long carbon fiber rod is 0.5 to 5 cm, and the diameter of the long carbon fiber rod is 0.5 to 5 mm; the length of the long carbon fiber bundle is 0.5 to 2 cm, and the diameter is 0.3 to 1.5 mm.

[0027] Optionally, the long carbon fiber is a resin long carbon fiber rod, the resin long carbon fiber rod comprises epoxy resin and carbon fiber, and based on the mass of the resin long carbon fiber rod, the content of epoxy resin in the long carbon fiber rod is 7-15wt%, and the content of carbon fiber is 85-93wt%;

[0028] In step S2, the method for preparing the solidified embryo body further comprises:

[0029] Insert the long carbon fiber rod into the blind hole, fill the mixture in step S1 into the molding cavity of the mold, press down the upper pressure head, and introduce the long carbon fiber rod into the through hole to perform pressurized curing to obtain the cured embryo.

[0030] Optionally, the long carbon fiber is a long carbon fiber bundle;

[0031] In step S2, the method for preparing the solidified embryo body further comprises:

[0032] a. mixing silicon carbide particles, thermosetting resin monomer and solvent to obtain a coating slurry;

[0033] b. applying the coating slurry on the surface of the long carbon fiber bundle and drying it to obtain a coated carbon fiber bundle;

[0034] c. Filling the mixture into the molding cavity of the mold, inserting the coated long carbon fiber bundle into the blind hole, pressing down the upper pressure head to guide the coated long carbon fiber bundle into the through hole, and performing pressurized curing treatment to obtain the cured embryo.

[0035] Optionally, the method further comprises: before the carbonization treatment, removing long carbon fibers above the surface of the solidified embryonic body.

[0036] Optionally, based on the mass of the coating slurry, the content of silicon carbide particles in the coating slurry is 30 to 50% by weight, the content of thermosetting resin monomer is 10 to 50% by weight, and the content of solvent is 30 to 40% by weight;

[0037] Optionally, in step S1, the mixing time is 2 to 4 hours; the drying conditions include: the drying temperature is 40 to 90° C., and the drying time is 8 to 12 hours;

[0038] In step S2, the conditions of the pressurized curing treatment include: a pressure of 5 to 30 MPa, a curing temperature of 100 to 150° C., and a heat preservation time of 1.5 to 3 hours;

[0039] In step S3, the carbonization treatment conditions include: carbonization temperature is 800-1200°C, and the insulation time is 2-6h;

[0040] The reaction conditions of the liquid phase siliconization include: the silicon source is selected from silicon powder, the average particle size of the silicon powder is 200-500 μm, the melting temperature is 1500-1900° C., and the insulation time is 2-4 hours.

[0041] A third aspect of the present invention provides a ceramic brake disc prepared by the method described in the second aspect of the present invention.

[0042] A fourth aspect of the present invention provides use of the ceramic brake disc described in the third aspect of the present invention in a vehicle or an aircraft.

[0043] Through the above technical scheme, the preparation method provided by the present invention inserts long carbon fibers into a mold and fills the mold with a short fiber mixture, and then molds and prepares a ceramic brake disc. The present invention opens a through hole on the upper pressure head of the mold and opens a blind hole matching the through hole on the molding surface of the lower pressure head of the mold to limit the displacement of the carbon fiber during the molding process, so that the carbon fiber can be evenly distributed in the mold along the pressure direction and has good Z-direction orientation. The prepared ceramic brake disc has vertical carbon fibers running through the thickness direction of the disc, which effectively increases the bending strength and shear strength of the ceramic brake disc along the Z-direction, thereby significantly improving the mechanical strength and mechanical properties of the ceramic brake disc. At the same time, the preparation cost is low and the preparation process is simple.

[0044] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0046] Figure 1 This is the ceramic brake disc prepared in Example 1 of the present invention.

[0047] Figure 2 This is a schematic structural diagram of the mold provided in Example 1 of the present invention.

[0048] Description of Reference Numerals

[0049] 1. Through hole opened by the upper pressing head of the mold; 2. Long carbon fiber; 3. Blind hole opened by the lower pressing head of the mold. DETAILED DESCRIPTION

[0050] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0051] A first aspect of the present disclosure provides a ceramic brake disc, wherein the ceramic brake disc comprises a disc substrate having a first surface and a second surface opposite to each other; the disc substrate comprises silicon carbide, free silicon, short fiber bundles and long carbon fibers;

[0052] Wherein, the carbon fibers extend from the first surface to the second surface.

[0053] In a specific embodiment of the present disclosure, the angle between the carbon fiber and the thickness direction of the brake disc is within 20°, preferably within 10°.

[0054] In a specific embodiment of the present disclosure, the long carbon fibers include long carbon fiber rods or long carbon fiber bundles; wherein the spacing between two adjacent long carbon fibers is 3 to 30 mm, preferably 3 to 15 mm.

[0055] In the above embodiment, a plurality of long carbon fibers are evenly distributed in the disk matrix, so that the overall strength of the disk matrix is ​​further improved. In another embodiment, a plurality of groups of long carbon fibers are distributed in the disk matrix, each group may include a plurality of, preferably 2 to 5, long carbon fibers, and the spacing between two adjacent groups of long carbon fibers is 3 to 30 mm, preferably 3 to 15 mm.

[0056] In a specific embodiment of the present disclosure, the long carbon fiber includes a long carbon fiber rod or a long carbon fiber bundle; the diameter of the long carbon fiber rod is 0.5-5 mm, preferably 0.5-1.5 mm, and the diameter of the long carbon fiber bundle is 0.5-2 mm, preferably 0.5-1 mm.

[0057] In a specific embodiment of the present disclosure, the length of the long carbon fiber is 2 to 5 cm, preferably 3 to 4 cm.

[0058] In a specific embodiment of the present disclosure, the length of the short fiber bundle is 0.5 to 1.5 cm, preferably 0.8 to 1.3 cm, and the diameter of the short fiber bundle is 0.3 to 0.6 mm, preferably 0.4 to 0.5 mm.

[0059] In a specific embodiment of the present disclosure, based on the mass of the ceramic brake disc, the content of silicon carbide in the ceramic brake disc is 45-65wt%, preferably 50-60wt%, the content of free silicon is 5-12wt%, preferably 7-10wt%, the content of long carbon fiber is 3-8wt%, preferably 4-7wt%, and the content of short fiber bundles is 27-42wt%, preferably 30-40wt%.

[0060] In a specific embodiment of the present disclosure, the average particle size of the carbon powder is 0.5 to 20 μm, preferably 0.5 to 10 μm.

[0061] In a specific embodiment of the present disclosure, the density of the ceramic brake disc is 2.0-2.5 g / cm 3 , preferably 2.1 to 2.3 g / cm 3 The ceramic brake disc has a bending strength in a direction parallel to the friction surface of more than 120 MPa, preferably 120-180 MPa, a compressive strength of more than 240 MPa, preferably 240-300 MPa, a bending strength in the Z-direction of more than 80 MPa, preferably 80-130 MPa, and a shear strength of more than 12 MPa, preferably 12-20 MPa.

[0062] The ceramic brake disc prepared in the present invention has continuous and uniform vertical carbon fibers in its disc matrix, which effectively increases the bending strength and shear strength of the ceramic brake disc along the Z-direction, thereby further improving the mechanical strength and mechanical properties of the ceramic brake disc.

[0063] A second aspect of the present disclosure provides a method for preparing a ceramic brake disc, wherein the method comprises:

[0064] S1, mixing carbon powder, thermosetting resin monomer, silicon carbide powder, short fiber bundles and solvent, drying, separating agglomerated short fiber bundles, and obtaining a mixture;

[0065] S2, placing the long carbon fiber and the mixed material in a molding cavity of a mold respectively, and performing pressurized curing treatment to obtain a cured embryo;

[0066] S3, sequentially subjecting the solidified embryo to carbonization treatment and liquid phase siliconization;

[0067] Wherein, the mold includes an upper press head and a lower press head; the upper press head is provided with a through hole; the molding surface of the lower press head is provided with a blind hole matching the through hole, and during the pressurized curing process of step S2, the long carbon fiber is limited by the blind hole and the through hole to extend in a direction perpendicular to the disk surface.

[0068] The preparation method provided by the present invention inserts carbon fiber into a mold and fills it with a short fiber mixture, and then molds it to prepare a ceramic brake disc. The present invention sets a blind hole on the lower pressure head of the mold to fix the carbon fiber in the blind hole, and sets a through hole on the upper pressure head of the mold to limit the displacement of the carbon fiber during the molding process, so that the carbon fiber can be evenly distributed along the pressure direction in the mold and has good axial orientation. The prepared ceramic brake disc has continuous and uniform vertical carbon fiber, which effectively increases the bending strength and shear strength of the ceramic brake disc along the Z-direction, thereby significantly improving the mechanical strength and mechanical properties of the ceramic brake disc. At the same time, the preparation cost is low and the preparation process is simple.

[0069] In a specific embodiment of the present disclosure, the through holes and the blind holes are distributed in an array; the apertures of the through holes and the blind holes are 0.5 to 5 mm, preferably 0.5 to 2 mm, and the hole spacing is 3 to 30 mm, preferably 3 to 15 mm; each of the through holes contains 1 to 5 long carbon fibers, preferably 1 long carbon fiber.

[0070] In the above embodiment, the number, hole diameter and hole spacing of the blind holes and the through holes are equal and the positions correspond one to one. Controlling the hole diameter, hole spacing and distribution of the through holes and blind holes on the mold within the specified range of the present invention can better fix the resin long carbon fiber rod in the mold so that it does not move during the molding process, so that the carbon fiber can be evenly distributed in the mold along the pressure direction. The prepared ceramic brake disc has continuous and uniform vertical carbon fibers, which effectively increases the bending strength and shear strength of the ceramic brake disc along the Z-direction, thereby further improving the mechanical strength and mechanical properties of the ceramic brake disc.

[0071] In a specific embodiment of the present disclosure, the ratio of the diameter of the long carbon fiber to the diameter of the blind hole is (0.9-0.97):1, preferably (0.95-0.97):1.

[0072] In a specific embodiment of the present disclosure, based on the mass of the mixture, the content of carbon powder in the mixture is 10-30wt%, preferably 15-20wt%, the content of thermosetting resin monomer is 15-40wt%, preferably 20-30wt%, the content of silicon carbide powder is 0.1-25wt%, preferably 10-12wt%, the content of short fiber bundles is 30-60wt%, preferably 45-55wt%, and the content of solvent is 10-30wt%, preferably 15-30wt%.

[0073] In a specific embodiment of the present disclosure, the length of the short fiber bundle is 0.5 to 1.5 cm, preferably 0.8 to 1.2 cm, and the diameter of the short fiber bundle is 0.3 to 1.5 mm, preferably 0.5 to 0.8 mm.

[0074] In a specific embodiment of the present disclosure, the thermosetting resin monomer is selected from one or more of phenolic resin, epoxy resin and furan resin, preferably phenolic resin; the solvent is selected from one or more of ethanol and tetramethylammonium hydroxide, preferably ethanol.

[0075] In a specific embodiment of the present disclosure, the long carbon fiber is a resin long carbon fiber rod or a long carbon fiber bundle; the length of the resin long carbon fiber rod is 2 to 5 cm, preferably 3 to 4 cm, and the diameter of the resin long carbon fiber rod is 0.5 to 5 mm, preferably 0.5 to 1.5 mm; the length of the long fiber bundle is 2 to 4 cm, preferably 3 to 4 cm, and the diameter is 0.3 to 1.5 mm, preferably 0.5 to 1.0 mm.

[0076] In the above embodiment, when the diameter of the long carbon fiber rod is controlled to be suitable for the aperture of the through hole and the blind hole of the mold, the uniformity and axial orientation of the carbon fiber in the mold can be further improved, so that the bending strength and shear strength of the ceramic brake disc along the Z-direction are enhanced, thereby further improving the mechanical strength and mechanical properties of the ceramic brake disc.

[0077] In a specific embodiment of the present disclosure, the long carbon fiber is a long carbon fiber rod; the resin long carbon fiber rod comprises epoxy resin and carbon fiber, and based on the mass of the resin long carbon fiber rod, the content of epoxy resin in the resin long carbon fiber rod is 7-15wt%, preferably 9-13wt%, and the content of carbon fiber is 85-93wt%, preferably 87-91wt%;

[0078] In step S2, the method for preparing the solidified embryo body further comprises:

[0079] Insert the resin long carbon fiber rod into the blind hole, fill the mixture in step S1 into the molding cavity of the mold, press down the upper pressure head to guide the resin long carbon fiber rod into the through hole, perform pressurized curing treatment, and obtain the cured embryo.

[0080] In another specific embodiment of the present disclosure, the long carbon fiber is a long carbon fiber bundle; in step S2, the method for preparing the solidified embryo body further includes:

[0081] a. mixing silicon carbide particles, thermosetting resin monomer and solvent to obtain a coating slurry;

[0082] b. applying the coating slurry on the surface of the long carbon fiber bundle and drying it to obtain a coated long carbon fiber bundle;

[0083] c. Filling the mixture into the molding cavity of the mold, inserting the coated long carbon fiber bundle into the blind hole, pressing down the upper pressure head to guide the coated long carbon fiber bundle into the through hole, and performing pressurized curing treatment to obtain the cured embryo.

[0084] In the above embodiment, since the hardness of the long carbon fiber bundle is lower than that of the long carbon fiber rod, it is necessary to insert a mold that has been immersed in the short fiber bundle mixture in advance to ensure that the long carbon fiber bundle will not break during the pressing process, so that the pressed long carbon fiber bundle can also be evenly distributed in the disc matrix of the ceramic brake disc with good axial orientation, so that the prepared ceramic brake disc has good mechanical strength and mechanical properties.

[0085] In another specific embodiment of the present disclosure, the method further comprises: before the carbonization treatment, removing the long carbon fibers above the surface of the solidified embryonic body.

[0086] In a specific embodiment of the present disclosure, based on the mass of the coating slurry, the content of silicon carbide particles in the coating slurry is 30 to 50% by weight, preferably 35 to 45% by weight, the content of thermosetting resin is 10 to 50% by weight, preferably 20 to 35% by weight, and the content of solvent is 30 to 40% by weight, preferably 33 to 37% by weight;

[0087] In a specific embodiment of the present disclosure, in step S1, the mixing time is 2 to 4 hours, preferably 2 to 3 hours; the drying conditions include: the drying temperature is 40 to 70° C., the drying time is 8 to 12 hours, preferably, the drying temperature is 50 to 60° C., and the drying time is 9 to 10 hours;

[0088] In step S2, the conditions of the pressurized curing treatment include: a pressure of 5 to 30 MPa, a curing temperature of 100 to 150° C., and a heat preservation time of 1.5 to 3 hours. Preferably, the pressure is 15 to 25 MPa, the curing temperature is 120 to 150° C., and the heat preservation time is 1.5 to 2.5 hours.

[0089] In step S3, the carbonization treatment conditions include: carbonization temperature of 800-1200° C., insulation time of 2-6 hours, preferably, carbonization temperature of 900-1000° C., insulation time of 3-4 hours;

[0090] The reaction conditions of the liquid phase siliconization include: the silicon source is selected from silicon powder, the average particle size of the silicon powder is 200-500μm, the melt infiltration temperature is 1500-1900℃, and the insulation time is 2-4h. Preferably, the melt infiltration temperature is 1600-1750℃, and the insulation time is 1-2h.

[0091] A third aspect of the present disclosure provides a ceramic brake disc prepared by the method described in the second aspect of the present disclosure.

[0092] A fourth aspect of the present disclosure provides use of the ceramic brake disc described in the third aspect of the present disclosure in a vehicle or an aircraft.

[0093] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0094] Example 1

[0095] a. According to the raw materials with a carbon powder content of 10wt%, a thermosetting resin monomer content of 20wt%, a silicon carbide powder content of 10wt%, a short fiber bundle content of 40wt%, and an alcohol content of 20wt%, after mixing and stirring for 2h, a mixture is obtained, wherein the short fiber bundle has a diameter of 0.4mm and a length of 1cm;

[0096] b. Insert the long carbon fiber rod into the blind hole of the lower pressure head of the mold, fill the mixture in step a into the mold, press down the upper pressure head of the mold, and introduce the long carbon fiber rod into the preset through hole of the upper pressure head, and pressurize and cure for 3 hours at 150° C., and the curing pressure is 20 MPa to obtain a cured embryo, wherein the mass ratio of the mixture in step a to the long carbon fiber rod is 95:5; the diameter of the long carbon fiber rod (containing 10wt% of epoxy resin and 90wt% of carbon fiber) is 1mm, and the length is 4cm, the hole diameter of the through hole of the upper pressure head and the blind hole of the lower pressure head is 1.04mm, the hole spacing is 10mm, each blind hole contains 1 long carbon fiber rod, and the ratio of the diameter of the long carbon fiber rod to the hole diameter of the blind hole is 0.96:1;

[0097] c. taking the solidified embryo body in step b out of the mold, removing the long carbon fiber rods above the surface, and then putting it into a carbonization furnace for carbonization treatment and removing burrs and processing heat dissipation holes to obtain a carbonized embryo body, wherein the carbonization temperature is 1000° C. and the holding time is 4 hours;

[0098] d. Liquid phase siliconization is performed on the carbonized body in step c to obtain a carbon ceramic body, wherein the silicon source is pure silicon powder, the melt infiltration temperature is 1800° C., and the holding time is 4 hours.

[0099] e. Mechanically process the surface and side of the carbon ceramic body in step d to obtain a ceramic brake disc.

[0100] Example 2

[0101] a. A raw material having a carbon powder content of 10wt%, a thermosetting resin monomer content of 20wt%, a silicon carbide powder content of 10wt%, a short fiber bundle content of 40wt%, and an alcohol content of 20wt% is stirred for 2h to obtain a mixture, wherein the short fiber bundle has a diameter of 0.6mm and a length of 1cm;

[0102] b. Mixing liquid phenolic resin and alcohol to obtain a coating slurry, wherein the mass ratio of phenolic resin monomer to alcohol is 1:1;

[0103] c. applying the coating slurry in step b to the surface of the long carbon fiber bundle, and placing it in an oven at 60° C. to completely dry the ethanol to obtain the coated long carbon fiber bundle, wherein the mass ratio of the coating slurry in step b to the long carbon fiber bundle is 2:9;

[0104] d. Fill the mixture in step a into the mold, and insert the coated long carbon fiber bundle into the mixture, wherein the mass ratio of the mixture in step a to the long carbon fiber bundle is 95:5, press down the upper pressing head of the mold, and pressurize and cure for 3 hours at 150° C., and the curing pressure is 20 MPa to obtain a cured embryo, wherein each long carbon fiber bundle has a diameter of 1 mm and a length of 4 cm, the aperture of the through hole of the upper pressing head and the blind hole of the lower pressing head is 1.04 mm, the hole spacing is 10 mm, and the ratio of the hole diameter of the long carbon fiber bundle to the blind hole is 0.96:1;

[0105] e. taking the solidified embryo body in step b out of the mold, removing the long carbon fibers above the surface, and then putting it into a carbonization furnace for carbonization treatment and removing burrs and processing heat dissipation holes to obtain a carbonized embryo body, wherein the carbonization temperature is 1000° C. and the holding time is 3 hours;

[0106] f. Liquid phase siliconization is performed on the carbonized body in step c to obtain a carbon ceramic body, wherein the silicon source is pure silicon powder, the melt infiltration temperature is 1850° C., and the holding time is 4 hours.

[0107] g. Mechanically process the surface and side of the carbon ceramic body in step d to obtain a ceramic brake disc.

[0108] Example 3

[0109] The method of Example 1 is adopted, with the only difference that in step b, the diameter of the long carbon fiber rod is 1.2 mm, the diameter of the through hole and the blind hole is 2 mm, each blind hole contains one long carbon fiber rod, and the ratio of the diameter of the long carbon fiber rod to the diameter of the blind hole is 0.6:1.

[0110] Example 4

[0111] The method of Example 1 is adopted, the only difference being that in step b, each blind hole contains 6 long carbon fiber rods.

[0112] Comparative Example 1

[0113] a. Filling a long carbon fiber rod (with the same specifications and dimensions as those in Example 1) and a short fiber filler into a mold, pressing down the upper pressure head of the mold, and pressurizing and curing at 150° C. for 3 h at a curing pressure of 20 MPa to obtain a cured embryo, wherein the upper pressure head and the lower pressure head of the mold used do not contain through holes and blind holes;

[0114] b. taking the solidified embryo body in step a out of the mold, placing it in a carbonization furnace for carbonization treatment, removing burrs and processing heat dissipation holes to obtain a carbonized embryo body, wherein the carbonization temperature is 1000° C. and the holding time is 4 hours;

[0115] c. Liquid phase siliconization of the carbonized body in step b is performed to obtain a carbon ceramic body, wherein the silicon source is pure silicon powder, the melt infiltration temperature is 1750° C., and the holding time is 3 hours.

[0116] d. Mechanically process the surface and side of the carbon ceramic body in step c to obtain a ceramic brake disc.

[0117] Test Case

[0118] The ceramic brake discs prepared in Examples 1 to 4 and Comparative Example 1 were tested as follows:

[0119] The flexural strength of the prepared product was measured by a universal testing machine (WDW-05), and the test standard was GB / T 6569.

[0120] The compressive strength of the prepared product was measured by a universal testing machine (WDW-05), and the test standard was GB / T 34559.

[0121] The bending strength of the prepared product in the Z-direction was measured by a universal testing machine (WDW-05), and the test standard was GB / T6569.

[0122] The shear strength of the prepared product was measured by a universal testing machine (WDW-05), and the test standard was ASTM D2344 / D2344M-13.

[0123] The angle between the vertical carbon fiber and the thickness direction of the brake disc was measured by a microscopic scanner (equipment model Leica DM3000). The angle between 100 long fiber bundles and the thickness direction was tested and the average value was calculated.

[0124] Table 1

[0125]

[0126] Table 2

[0127]

[0128] According to the test results in Table 1 and Table 2, it can be seen that the carbon-ceramic brake disc provided by the present invention has continuous and uniform vertical carbon fibers compared with the comparative example, and the average angle of the vertical carbon fibers in the thickness direction of the brake disc can be controlled below 20°. The bending strength and shear strength of the ceramic brake disc along the Z-direction are significantly improved, and it has high bending and compressive strength, excellent mechanical strength and mechanical properties. At the same time, the preparation cost is low and the preparation process is simple.

[0129] It can be seen from the test results of Example 1 that when the preparation method, the type of long carbon fiber used, the preparation of the components in the mixture, the mold used and the specifications of the mold are within the specified range of the present invention, the effect and performance of the product prepared by the present invention can be improved; from the test results of Examples 2 to 4, it can be seen that when the type of long carbon fiber used, the hole diameters of the through holes and blind holes in the mold, the diameter of the long carbon fiber, and the number of long carbon fibers contained in each blind hole are all within the preferred range of the present invention, the bending strength and shear strength of the ceramic brake disc prepared by the present invention along the Z-direction can be further improved, so that the ceramic brake disc has better mechanical strength and mechanical properties.

[0130] It can be seen from the test results of Comparative Example 1 that since Comparative Example 1 adopts the conventional method for preparing ceramic brake discs, during the dry pressing process, the carbon fibers will be broken under the action of pressure, or most of them tend to be distributed horizontally, so that the average angle between the vertical fibers in the ceramic brake disc and the thickness direction of the brake disc is above 20°, resulting in the prepared ceramic brake disc having a bending strength and shear strength along the Z-direction that are significantly lower than those of Examples 1 to 4, and its bending strength and compressive strength are significantly reduced, and its mechanical strength and mechanical properties are poor.

[0131] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0132] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0133] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A ceramic brake disc, wherein: The ceramic brake disc comprises a disc substrate having a first surface and a second surface opposite to each other; the disc substrate comprises silicon carbide, free silicon, short fiber bundles and long carbon fibers; Wherein, the long carbon fibers extend from the first surface to the second surface.

2. The ceramic brake disc according to claim 1, wherein: The angle between the long carbon fiber and the thickness direction of the brake disc is within 20°.

3. The ceramic brake disc according to claim 1, wherein: The long carbon fiber comprises a long carbon fiber rod or a long carbon fiber bundle; Wherein, the distance between two adjacent long carbon fibers is 3 to 30 mm.

4. The ceramic brake disc according to claim 3, wherein: The diameter of the long carbon fiber rod is 0.5-5 mm, and the diameter of each long carbon fiber bundle is 0.5-2 mm.

5. The ceramic brake disc according to claim 1, wherein: The length of the long carbon fiber is 2 to 5 cm.

6. The ceramic brake disc according to claim 1, wherein: The length of the short fiber bundle is 0.5 to 1.5 cm, and the diameter of the short fiber bundle is 0.3 to 0.6 mm.

7. The ceramic brake disc according to claim 1, wherein: Based on the mass of the ceramic brake disc, the content of silicon carbide in the ceramic brake disc is 45-65wt%, the content of free silicon is 5-12wt%, the content of long carbon fiber is 3-8wt%, and the content of short fiber bundle is 27-42wt%.

8. The ceramic brake disc according to claim 1, wherein: The average particle size of the carbon powder is 0.5 to 20 μm.

9. The ceramic brake disc according to claim 1, wherein: The density of the ceramic brake disc is 2.0-2.5 g / cm 3 The ceramic brake disc has a bending strength of more than 120 MPa in a direction parallel to the friction surface, a compressive strength of more than 240 MPa, a bending strength of more than 80 MPa in the Z-direction, and a shear strength of more than 12 MPa.

10. A method for preparing a ceramic brake disc, wherein: The method includes: S1, mixing carbon powder, thermosetting resin monomer, silicon carbide powder, short fiber bundles and solvent, drying, separating agglomerated short fiber bundles, and obtaining a mixture; S2, placing the long carbon fiber and the mixed material in a molding cavity of a mold respectively, and performing pressurized curing treatment to obtain a cured embryo; S3, sequentially subjecting the solidified embryo to carbonization treatment and liquid phase siliconization; Wherein, the mold includes an upper press head and a lower press head; the upper press head is provided with a through hole; the molding surface of the lower press head is provided with a blind hole matching the through hole, and during the pressurized curing process of step S2, the long carbon fiber is limited by the blind hole and the through hole to extend in a direction perpendicular to the disk surface.

11. The method according to claim 10, wherein: The through holes and the blind holes are distributed in an array; the diameters of the through holes and the blind holes are 0.5 to 5 mm, and the hole spacing is 3 to 30 mm; and each of the through holes contains 1 to 5 long carbon fibers.

12. The method according to claim 10, wherein: The ratio of the diameter of the long carbon fiber to the diameter of the blind hole is (0.9-0.97):

1.

13. The method according to claim 10, wherein: Based on the mass of the mixture, the content of carbon powder in the mixture is 10-30wt%, the content of thermosetting resin monomer is 15-40wt%, the content of silicon carbide powder is 0.1-25wt%, the content of short fiber bundle is 30-60wt%, and the content of solvent is 10-30wt%; The length of the short fiber bundle is 0.5 to 1.5 cm, and the diameter of the short fiber bundle is 0.3 to 0.6 mm; The thermosetting resin monomer is selected from one or more of phenolic resin, epoxy resin and furan resin; the solvent is selected from one or more of ethanol and tetramethylammonium hydroxide.

14. The method according to claim 10, wherein: The long carbon fiber is a resin long carbon fiber rod or a long carbon fiber bundle; the length of the resin long carbon fiber rod is 2-5cm, and the diameter of the resin long carbon fiber rod is 0.5-5mm; the length of the long carbon fiber bundle is 2-5cm, and the diameter is 0.3-1.5mm.

15. The method according to claim 10 or 14, wherein: The long carbon fiber is a resin long carbon fiber rod, and the resin long carbon fiber rod comprises epoxy resin and carbon fiber. Based on the mass of the resin long carbon fiber rod, the content of epoxy resin in the resin long carbon fiber rod is 7-15wt%, and the content of carbon fiber is 85-93wt%; In step S2, the method for preparing the solidified embryo body further comprises: Insert the resin long carbon fiber rod into the blind hole, fill the mixture in step S1 into the molding cavity of the mold, press down the upper pressure head to guide the resin long carbon fiber rod into the through hole, perform pressurized curing treatment, and obtain the cured embryo.

16. The method according to claim 10 or 14, wherein: The long carbon fiber is a long carbon fiber bundle. In step S2, the method for preparing the solidified embryo body further includes: a. mixing silicon carbide particles, thermosetting resin monomer and solvent to obtain a coating slurry; b. applying the coating slurry on the surface of the long carbon fiber bundle and drying it to obtain a coated long carbon fiber bundle; c. Filling the mixture into the molding cavity of the mold, inserting the long fibers of the coated long carbon fiber bundle into the blind hole, pressing down the upper pressure head to guide the coated long carbon fiber bundle into the through hole, and performing pressurized curing treatment to obtain the cured embryo.

17. The method according to claim 10, wherein: The method further comprises: before the carbonization treatment, removing the long carbon fibers above the surface of the solidified embryonic body.

18. The method according to claim 16, wherein: Based on the mass of the coating slurry, the content of silicon carbide particles in the coating slurry is 30 to 50% by weight, the content of thermosetting resin monomer is 10 to 50% by weight, and the content of solvent is 30 to 40% by weight.

19. The method according to claim 10, wherein: In step S1, the mixing time is 2 to 4 hours; the drying conditions include: the drying temperature is 40 to 90° C., and the drying time is 8 to 12 hours; In step S2, the conditions of the pressurized curing treatment include: a pressure of 5 to 30 MPa, a curing temperature of 100 to 150° C., and a heat preservation time of 1.5 to 3 hours; In step S3, the carbonization treatment conditions include: carbonization temperature is 800-1200°C, and the insulation time is 2-6h; The reaction conditions of the liquid phase siliconization include: the silicon source is selected from silicon powder, the average particle size of the silicon powder is 200-500 μm, the melting temperature is 1500-1900° C., and the insulation time is 2-4 hours.

20. A ceramic brake disc prepared by the method according to any one of claims 10 to 19.

21. Use of the ceramic brake disc according to claim 20 in a vehicle or an aircraft.

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