High-entropy carbide coated brake disc and method of making same

Abstract

The application discloses a high-entropy carbide coating brake disc and a preparation method thereof, and belongs to the technical field of brake disc coating material preparation. The preparation method of the high-entropy carbide coating brake disc, wherein the high-entropy carbide coating brake disc comprises a high-entropy carbide coating and a base body, comprises the following steps: S1, powder is proportioned according to requirements, and then mixed uniformly through ball milling to obtain a mixture; S2, the mixture is pressed and sintered to obtain a block body, and the block body is ball milled and sieved to obtain carbide powder; S3, the carbide powder and a binder phase are mixed into slurry, and the slurry is granulated to obtain granulated powder; and S4, the granulated powder is deposited on the surface of the base body through laser cladding to form a high-entropy carbide coating, thereby obtaining the high-entropy carbide coating brake disc. The high-entropy carbide coating brake disc prepared by the application has high hardness and good wear resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of brake disc coating materials, and particularly relates to a high-entropy carbide coating brake disc and a preparation method thereof. BACKGROUND

[0002] A brake system is a crucial component in the automotive field, which is directly related to the safety of the automobile in use and the reliability of the automobile in parking. As a core component of the brake system, a brake disc needs to operate under harsh working conditions and bear repeated mechanical load and thermal load, which is easy to cause friction noise and surface wear.

[0003] The main material of the brake disc is generally cast iron; in addition, the wear of the cast iron brake disc also produces fine particle dust, which pollutes the environment. A severely worn brake disc can cause the actual braking distance of the automobile to exceed the expectation, affecting the maneuverability and safety of driving. SUMMARY

[0004] The application overcomes the above technical problems and provides a high-entropy carbide coating brake disc and a preparation method thereof. The high-entropy carbide coating brake disc has high hardness and excellent wear resistance, and the preparation method is simple and suitable for industrial production.

[0005] The application solves the above technical problems through the following technical solutions.

[0006] A preparation method of a high-entropy carbide coating brake disc, the high-entropy carbide coating brake disc comprising a high-entropy carbide coating and a substrate; the preparation raw material of the high-entropy carbide coating comprises a powder and a binder phase, the powder comprising TiO2 powder, Nb2O5 powder, Ta2O5 powder, W powder, and carbon black;

[0007] The preparation method of the high-entropy carbide coating brake disc comprises the following steps:

[0008] S1. The powder is proportioned as required, and then mixed uniformly by ball milling to obtain a mixture;

[0009] S2. The mixture is pressed and sintered to obtain a block, and the block is ball milled and sieved to obtain a carbide powder; the sintering temperature is 2200-2300 DEG C;

[0010] S3. The carbide powder and the binder phase are mixed into a slurry, and the slurry is granulated to obtain granulated powder;

[0011] S4. The granulated powder is deposited on the surface of the substrate by laser cladding to form a high-entropy carbide coating, thereby obtaining a high-entropy carbide coating brake disc;

[0012] The laser power of the laser cladding is 1500-3000W, the laser scanning speed of the laser cladding is 8-20mm / s, and the overlap rate of the laser cladding is 30-60%.

[0013] In the application, the molar ratio of Ti:Ta:Nb:W in the powder is x:y:z:1-x-y-z, wherein 0

[0014] In the application, the molar ratio of the carbon element in the carbon black to the total molar amount of titanium element, tantalum element, niobium element and tungsten element in the powder is 1-3:1, preferably 1-2:1, more preferably 1.0-1.5:1, for example 1:1.

[0015] In the application, the binder phase is a Ni-based alloy powder, an Fe-based alloy powder or a Co-based alloy powder.

[0016] Further, the Ni-based alloy powder includes a nickel-copper high-temperature alloy powder, a nickel-based corrosion-resistant alloy powder and a nickel-based wear-resistant alloy powder; the nickel-copper high-temperature alloy powder comprises chromium, tungsten, molybdenum, cobalt, aluminum, titanium, boron and zirconium; the nickel-based corrosion-resistant alloy powder is a nickel-copper alloy, a nickel-chromium alloy, a nickel-molybdenum alloy or a nickel-chromium-molybdenum alloy; and the nickel-based wear-resistant alloy powder comprises chromium, molybdenum, tungsten, niobium, tantalum and indium.

[0017] Further, the Fe-based alloy powder is a martensitic alloy steel, a high-chromium cast iron, an austenitic manganese steel or a martensitic stainless steel.

[0018] Further, the Co-based alloy powder includes a platinum-cobalt alloy, a samarium-cobalt alloy, a zirconium-cobalt alloy or a tungsten-cobalt alloy.

[0019] In the application, the D50 of the TiO2 powder, the Ta2O5 powder, the Nb2O5 powder and the W powder is 2-4μm.

[0020] In the application, the purity of the TiO2 powder, the Ta2O5 powder, the Nb2O5 powder and the W powder is ≥99.5%.

[0021] In the application, the D50 of the carbon black is 0.4-0.6μm.

[0022] In the application, the purity of the carbon black is ≥99.9%.

[0023] In S2, the presser pressure of the press is 80-100t, and the holding pressure time is 3-10min.

[0024] In S2, the sintering temperature is 2200-2300℃, and the sintering time is 4-6h.

[0025] In S2, the sintered product is cooled to room temperature in the furnace.

[0026] In S2, the particle size of the sieved product is 1-10μm.

[0027] In S3, the volume ratio of the carbide powder to the binder phase in the slurry is 5-8:1-3.

[0028] In S3, the mass ratio of the ethanol solution to the sum of the mass of the carbide powder and the binder phase to the mass of PEG2000 in the slurry is 100:60-75:0.5-2.

[0029] For example, the mass ratio of the ethanol solution to the sum of the mass of the carbide powder and the binder phase to the mass of PEG2000 in the slurry is 100:70:1.4.

[0030] The ethanol solution comprises 90% ethanol and 10% water.

[0031] In S3, the slurry further comprises a step of colloidal milling.

[0032] Further in S3, the colloidal milling time is 10-12h.

[0033] Further in S3, the colloidal milling further comprises adding 0.5-2wt% PEG4000 based on the mass of the ethanol solution.

[0034] In S3, the granulation further comprises a step of densification treatment.

[0035] Further in S3, the step of densification treatment comprises heating at 400-600℃ for 1-3h in a nitrogen atmosphere, then sintering at 800-1200℃ for 1.5-4.5h under vacuum, and then sieving through a 150-300 mesh sieve.

[0036] For example, the step of densification treatment comprises heating at 450℃ for 2h in a nitrogen atmosphere, then sintering at 900℃ for 2h under vacuum, and then sieving through a 200 mesh sieve.

[0037] In S4, the substrate is preheated, and the preheating temperature is 200-300℃.

[0038] In S4, the laser cladding is performed by a synchronous laser cladding method.

[0039] In S4, the laser power of the laser cladding is 2000-3000W, for example, 2000W, 2500W and 3000W.

[0040] In S4, the laser scanning speed of the laser cladding is 10-18 mm / s.

[0041] In S4, the overlap rate of the laser cladding is 40-50%.

[0042] In S4, the spot diameter of the laser cladding is 2-4 mm, preferably 3-4 mm.

[0043] In S4, the powder feeding rate of the laser cladding is 5-150 g / min, preferably 15-50 g / min.

[0044] In S4, the defocusing amount of the laser cladding is 0.5-1.5 mm, preferably 0.8-1.3 mm.

[0045] The application further discloses a high-entropy carbide coating brake disc prepared by the preparation method.

[0046] In the application, the material of the base body is gray cast iron.

[0047] In the application, the thickness of the high-entropy carbide coating is 0.2-2 mm, preferably, the thickness of the coating is 0.5-1.6 mm, for example, 1.3 mm.

[0048] In the application, the composition of the high-entropy carbide coating comprises (Ti x Nb y Ta z W 1-x-y-z )C, wherein 0

[0049] In the application, the single-track cladding dilution rate d of the high-entropy carbide coating is 20-30%, wherein d=D / (D+H), D is the single-track cladding depth, and H is the single-track cladding height.

[0050] In the application, the single-track cladding wh of the high-entropy carbide coating is 3.0-3.9, wh=W / H, wherein W represents the width of the high-entropy carbide coating cladding layer.

[0051] In the application, the single-track cladding wetting angle θ of the high-entropy carbide coating is 35-45°; wherein the wetting angle θ is used to represent the compatibility between the high-entropy carbide coating and the base body.

[0052] In the application, the average microhardness of the high-entropy carbide coating is 410-1280 HV0.5, for example, 688.2 HV0.5.

[0053] In the application, the friction coefficient of the high-entropy carbide coating brake disc is 0.27-0.35 mm 2N / m.

[0054] In the present application, the wear rate of the high-entropy carbide coating brake disc is 4*10 -4 ~ 100*10 -4 mm 3 / N·m, for example 6.56*10 -4 mm 3 / N·m.

[0055] On the basis of common sense in the art, the above-mentioned preferred conditions can be combined arbitrarily, i.e. to obtain each preferred example of the present application.

[0056] Compared with the prior art, the present application has the following beneficial effects:

[0057] The high-entropy carbide coating brake disc of the present application is prepared by laser cladding high-entropy carbide on the substrate. First, the appropriate powder components are selected, and then the conditions of laser cladding are strictly controlled. It is found through the research of the present application that the laser power and the laser scanning speed both have good bonding force and apparent quality when the high-entropy carbide coating is cladded on the substrate surface. Finally, the single-track cladding dilution rate d is 20-30%, the shape parameter wh is in the range of 3.0-3.9, and the wetting angle θ between the cladding layer and the substrate is 35-45°, so as to ensure that the high-entropy carbide coating cladded on the substrate has excellent apparent quality.

[0058] The high-entropy carbide coating brake disc of the present application has high hardness and good wear resistance. The average microhardness of the high-entropy carbide coating is 410-1280HV0.5; the friction coefficient of the high-entropy carbide coating brake disc is 0.27-0.35mm 2 / N·m, and the wear rate is 4*10 -4 ~ 100*10 -4 mm 3 / N·m. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 It is the product diagram of the high-entropy carbide coating brake disc of Example 1.

[0060] Figure 2 It is the cross-sectional SEM diagram of the high-entropy carbide coating and the substrate prepared by single-track cladding of Example 2.

[0061] Figure 3 It is the cross-sectional SEM diagram of the high-entropy carbide coating and the substrate prepared by multi-track cladding of Example 3.

[0062] Figure 4 It is the cladding morphology diagram of the high-entropy carbide coating of Example 3.

[0063] Figure 5 It is the hardness test comparison diagram of Test Example 1.

[0064] Figure 6 Friction coefficient test comparison chart for test example 2.

[0065] Figure 7 Wear rate test comparison chart for test example 2. DETAILED DESCRIPTION

[0066] In order to facilitate the understanding of the present application, the following will make a more comprehensive and detailed description of the present application in combination with the preferred embodiments, but the protection scope of the present application is not limited to the following specific embodiments.

[0067] Unless otherwise defined, all the professional terms used in the following have the same meaning as that generally understood by the person skilled in the art. The professional terms used in the present application are only for the purpose of describing the specific embodiments, and are not intended to limit the protection scope of the present application.

[0068] The particle size of TiO2 powder, Ta2O5 powder, Nb2O5 powder and W powder in the raw material for preparing the high-entropy carbide coating in the following examples and comparative examples is D50=2-4 μm, and the purity is all ≥99.5%; the particle size of carbon black is D50=0.4-0.6 μm, and the purity is all ≥99.9%.

[0069] The gray cast iron grade is HT250.

[0070] Preferably, the binder phase is NiCu element powder; in the NiCu element powder, the mass fraction of Ni is ≥63%; Cu: 28-34%; Fe ≤2.5%; Mn ≤2.2%; Si ≤0.5%; C ≤0.3%; S ≤0.024%.

[0071] In the specific mode of the present application, the ball mill adopts a hard alloy lining mixer, the grinding balls are tungsten carbide grinding balls, the grinding balls are large balls with a diameter of 10 mm and small balls with a diameter of 4 mm, and the mass ratio of the large balls to the small balls in the grinding balls is 1:1, and the mass ratio of the grinding balls to the powder is 4:1.

[0072] Example 1

[0073] 1. The high-entropy carbide coating brake disc in this embodiment comprises a high-entropy carbide coating and a substrate (gray cast iron).

[0074] The raw material for preparing the high-entropy carbide coating comprises a powder and a binder phase;

[0075] The powder is TiO2 powder, Ta2O5 powder, Nb2O5 powder, W powder and carbon black; the molar ratio of Ti:Nb:Ta:W in the powder is 3:1:1:1, and the molar amount of carbon element in the carbon black: the total molar amount of titanium element, tantalum element, niobium element and tungsten element in the powder is 1:1;

[0076] The binder phase is NiCu elemental powder (Ni: 63%; Cu: 31.676%; Fe: 2.5%; Mn: 2.0%; Si: 0.5%; C: 0.3%; S: 0.024%).

[0077] The thickness of the coating is 1.3 mm.

[0078] 2. The preparation method of the high-entropy carbide coating brake disc in this embodiment is as follows:

[0079] S1. The powders are proportioned as required, and then mixed uniformly after 10 h of ball milling to obtain a mixture;

[0080] S2. The mixture is poured into a mold and placed under a press with a pressure of 100 t for pressing, and the pressure is maintained for 4 min. Then, the temperature is raised to 2300°C in a carbon tube furnace, and sintering is performed at this temperature for 5 h. After the furnace is cooled to room temperature, a block is obtained;

[0081] The block is subjected to ball milling and sieving (through a 1500 mesh sieve) to obtain carbide powder with a composition of (Ti 1 / 2 Nb 1 / 6 Ta 1 / 6 W 1 / 6 )C;

[0082] S3. The carbide powder and the binder phase are mixed to form a slurry. The carbide powder and the binder phase are mixed in a volume ratio of 7:1. Then, the slurry is prepared by mixing 90% ethanol solution, the sum of the mass of the carbide powder and the binder phase, and PEG2000 in a mass ratio of 100:70:1.4. After 2 min of beating, the slurry is obtained;

[0083] Colloid milling: the slurry is ground for 12 h by a colloid mill, and then 1 wt% of the dispersant PEG4000 is added to the ethanol solution. Finally, the slurry is atomized and granulated;

[0084] Densification treatment: the slurry is heated at 450°C for 2 h in a nitrogen atmosphere to remove the solvent, and then the atomized and granulated powder is sintered at 900°C for 2 h under vacuum conditions to make it more dense. The granulated powder is sieved through a 200 mesh sieve. The granulated powder is spherical and meets the LC particle size requirement (15-150 μm).

[0085] S4. The substrate is preheated at 200-300°C, and the granulated powder is deposited onto the surface of the substrate by synchronous laser cladding. The laser power for laser cladding is 2500 W, the laser scanning speed is 10 mm / s, the overlap rate is 50%, the spot diameter is 4 mm, the powder feeding amount is 28.6 g / min, and the defocusing amount is 1 mm.

[0086] The granulated powder is deposited onto the surface of the substrate by laser cladding to form a high-entropy carbide coating. Figure 1 The high-entropy carbide coating brake disc product obtained in this embodiment is shown in the figure.

[0087] The following examples and test examples are only selected gray cast iron material base sample for the convenience of exploring the test and subsequent test, and gray cast iron brake disc is not selected as the test object.

[0088] Example 2

[0089] In this embodiment, the effects of different laser power (P) and laser scanning speed (v) of laser cladding on the coating quality of high-entropy carbide coated brake disc are explored, so the laser power (P) and laser scanning speed (v) of laser cladding are different from those of example 1, and other steps and parameters are the same as those of example 1.

[0090] According to the parameters in table 1, orthogonal test is carried out, and the corresponding test number under different laser power (P) and laser scanning speed (v) test is shown in the table. The test number in table 1 corresponds to Figure 2 Test number, Figure 2 The cross-sectional SEM image of high-entropy carbide coating prepared by single pass cladding and the substrate is shown in the figure. Figure 2 The abscissa is P (W), and the ordinate is v (mm / s).

[0091] Table 1

[0092]

[0093]

[0094] Note: ① in the table, P and v respectively refer to laser power P and laser scanning speed v; ② W, H and D respectively refer to the width, height and depth of single pass cladding layer measured in the test; ③ dilution rate d = D / (D+H); ④ width-height ratio wh = W / H.

[0095] The geometric morphology of the cladding layer (i.e. high-entropy carbide coating) is affected by multiple process parameters, including laser power, laser scanning speed, spot diameter, powder feeding speed and defocusing amount. Among these parameters, laser power and laser scanning speed have the most significant impact on the surface quality of the coating. Specifically, when the laser scanning speed v remains unchanged, as the laser power P increases, the surface quality of the coating improves. However, at a lower laser power P, as the scanning speed v increases, the coating height decreases, resulting in a decrease in cladding quality.

[0096] Based on the analysis of table 1 and Figure 2 The following conclusions can be drawn:

[0097] 1. Dilution rate d is an important factor affecting the quality of the cladding layer, and its calculation formula is d = D / (D + H), wherein D represents the single pass depth of high-entropy carbide coating, i.e. the depth of the cladding layer into the substrate; H represents the height of the high-entropy carbide coating, i.e. the increased height of the cladding layer relative to the surface of the substrate. Too low dilution rate will result in poor metallurgical bonding effect of the alloy surface, which is easy to fall off; and too high dilution rate will make the substrate composition of the cladding layer too much, resulting in poor crack and fusion. In this embodiment, the preferred dilution rate is 25% to 30%, and the cladding layer dilution rate of the test groups with test numbers 5, 9, 10, 17 and 18 is better.

[0098] 2. The shape parameter wh of the cladding layer can reflect the quality problem through the geometric characteristics of the cross section of the cladding layer, and its calculation formula is wh = W / H, wherein W represents the width of the high-entropy carbide coating, i.e. the coverage range of the cladding layer on the substrate surface. When the wh value is low, the cladding layer is easy to fall off from the substrate; and when wh = 3.0 to 3.9, there is good bonding between the cladding layer and the substrate. The shape parameter wh of the cladding layer of the test groups with test numbers 9, 12, 13, 17, 18, 21, 22, 23 and 24 is better.

[0099] 3. Wettability angle θ represents the contact between the cladding layer and the substrate, and its size can reflect the bonding force between the cladding layer and the substrate. Too large wettability angle θ indicates that the bonding force between the cladding layer and the substrate is insufficient, and too small wettability angle θ may have other problems. The preferred wettability angle θ range is 35 to 45°, and the wettability angle θ of the test groups with test numbers 5, 7, 8, 9, 10, 11, 12, 13, 16 and 21 is better.

[0100] Considering the results of all test groups, the preferred test group 9, i.e. the best process window is that the laser power P is 2500 W and the laser scanning speed v is 10 mm / s.

[0101] Embodiment 3

[0102] This embodiment explores the influence of the change of different overlap rates on the coating quality of high-entropy carbide coated brake disc. Under the test conditions of embodiment 1, other steps and parameters are kept unchanged, and only the overlap rate is adjusted to 30%, 40%, 50%, 60% and 70% respectively, and laser cladding experiment is carried out. The SEM diagram of the cross section of the high-entropy carbide coating and the substrate prepared by multi-pass cladding is as shown in Figure 3 , and the macroscopic cladding appearance is as shown in Figure 4 .

[0103] By analyzing Figure 3 , the following conclusions can be drawn:

[0104] 1. When the overlap ratio is low, such as 30%, the interface between the coating and the substrate appears "wavy", which means that the coating fails to completely cover the substrate, resulting in a smaller effective thickness of the coating.

[0105] 2. When the overlap rate is high, such as 70%, the bonding surface between the coating and the substrate is relatively smooth and the overlap is complete, but the coating width is limited. This will lead to a significant increase in the amount of cladding powder used, thereby reducing economic benefits.

[0106] Figure 4 The cladding morphology diagram with a 50% overlap rate shows a relatively smooth cladding layer surface, free from obvious defects such as pores, inclusions, or cracks, indicating a high coating quality. Therefore, considering the coating's adhesion, effective thickness, economic benefits, and microstructure quality, a 50% overlap rate was selected as the optimal overlap rate. This choice balances the coating's coverage and economic benefits, ensuring high coating quality.

[0107] Comparative Example 1

[0108] This comparative study investigates the effect of changes in the composition of high-entropy carbide coatings on the performance of high-entropy carbide-coated brake discs.

[0109] The difference between this comparative example and Example 1 is as follows:

[0110] The raw material for preparing the coating is only TiO2 powder, and the final TiC coating is obtained.

[0111] Test Example 1

[0112] The hardness results measured for Comparative Example 1 and Example 1 using different coatings are shown in [reference]. Figure 5 . Figure 5 The vertical axis represents hardness, measured in HV; the horizontal axis represents the test points, specifically the points taken at equal intervals from the coating to the substrate to test the hardness. The test points are adjusted by the instrument according to the thickness of the brake disc, and the test interval varies from tens to hundreds of micrometers.

[0113] Figure 5 The figures show the coating hardness test results for Example 1 and Comparative Example 1, combined with... Figure 5 It can be known that:

[0114] In Example 1, the average hardness of the high-entropy carbide coating was 688.2 HV0.5 (0.5 refers to a load of 0.5 kg), while in Comparative Example 1, the average hardness of the TiC coating was 456.2 HV0.5, and the average hardness of the gray cast iron substrate was 210.5 HV0.5.

[0115] It should be noted that the hardness distribution of high-entropy carbide coatings is uneven; therefore, the hardness values ​​obtained from hardness tests are average values.

[0116] The high-entropy carbide coating in Example 1 showed higher average hardness value than Comparative Example 1, which represented that the high-entropy carbide coating in Example 1 had better wear resistance and durability. Meanwhile, the hardness of the high-entropy carbide coating was significantly improved compared with the gray cast iron substrate, which helped to improve the overall performance of the substrate.

[0117] Test Example 2

[0118] This test example was determined by UMT-2 reciprocating friction and wear tester of Bruker U.S. Company (Bruker UMT, USA); SiN ball was used as the counterpart, friction load was 2000N, friction frequency was 900HZ, friction radius was 2mm, and time was set to 30s.

[0119] The friction coefficient test results of the TiC coating of Comparative Example 1 and the high-entropy carbide coating of Example 1 are shown in Table 1, and the wear rate test results are shown in Table 2. Figure 6 Figure 7 The wear rate refers to the volume lost per unit sliding distance and unit contact surface friction load; the friction coefficient refers to the area lost per unit sliding distance and unit contact surface friction load. By analyzing the data of Table 1 and Table 2, the following conclusions can be drawn: Figure 6 Figure 7

[0120] 1. The high-entropy carbide coating of Example 1 had a shorter time required for the running-in stage compared with the TiC coating of Comparative Example 1, and the high-entropy carbide coating of Example 1 could reach the stable running-in stage faster after the running-in stage. Therefore, the test results of Example 1 entered the stable stage in a shorter time, which indicated that the high-entropy carbide coating brake disc of the present application had better sensitivity and the characteristics of fast completion of the wear process.

[0121] 2. The friction coefficient of the TiC coating of Comparative Example 1 was stable at about 0.48, while the friction coefficient of the high-entropy carbide coating of Example 1 was stable at about 0.3, which indicated that the coating of Example 1 had a lower friction coefficient.

[0122] 3. In terms of wear rate, the wear rate of the high-entropy carbide coating of Example 1 was 0.000656, while the wear rate of the high-entropy carbide coating of Comparative Example 1 was 0.00106. This result proved that the high-entropy carbide coating of Example 1 had better strengthening effect under the "high mixing entropy" effect, thereby significantly improving the wear resistance of the coating.

[0123] ​​​High-entropy carbide coated brake discs, as a new type of wear-resistant material, have significant advantages. This high-entropy carbide coated brake disc not only has high wear resistance and durability, but also can maintain high braking force even after multiple braking operations. This coating technology not only reduces the wear and particle emission of the brake system, but also improves the overall braking performance, especially in continuous braking or harsh environments.

[0124] Unless otherwise specifically indicated, various materials, reagents, instruments and equipment and the like used in the present application can be purchased from the market or can be prepared by existing methods. The above specific examples further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method of manufacturing a high-entropy carbide coated brake disc, characterized in that, The high-entropy carbide coating brake disc comprises a high-entropy carbide coating and a substrate; the preparation raw material of the high-entropy carbide coating comprises a powder and a binder phase, and the powder comprises TiO2 powder, Nb2O5 powder, Ta2O5 powder, W powder and carbon black; The composition of the high-entropy carbide coating includes (Ti x Nb y Ta z W 1-x-y-z )C, wherein 0 < x < 1, 0 < y < 1, 0 < z < 1, 0 < 1-x-y-z < 1. The preparation method of the high-entropy carbide coating brake disc comprises the following steps: S1. The powder is proportioned as required, and then mixed uniformly by ball milling to obtain a mixture; S2. The mixture is pressed and sintered to obtain a block, and the block is ball milled and sieved to obtain a carbide powder; the sintering temperature is 2200-2300 DEG C; S3. The carbide powder and the binder phase are mixed into a slurry, and the volume ratio of the carbide powder to the binder phase is 5-8:1-3; the slurry is granulated to obtain granulated powder; the granulation further comprises a densification treatment step, and the densification treatment step is heating at 400-600 DEG C for 1-3 h in a nitrogen atmosphere, and then sintering at 800-1200 DEG C for 1.5-4.5 h under vacuum, and then sieving through a 150-300 mesh sieve; S4. The granulated powder is deposited on the surface of the substrate by laser cladding to form a high-entropy carbide coating, thereby obtaining a high-entropy carbide coating brake disc; The laser power of the laser cladding is 1500-3000 W, the laser scanning speed of the laser cladding is 8-20 mm / s, and the overlap rate of the laser cladding is 30-60%.

2. The method of claim 1, wherein the high-entropy carbide coated brake disc is prepared by the steps of: At least one of the following conditions a-b is met: a. The molar ratio of Ti:Ta:Nb:W in the powder is x:y:z:1-x-y-z, wherein 0 b. The molar amount of carbon in the carbon black:the total molar amount of titanium, tantalum, niobium and tungsten in the powder is 1-3:

1.

3. The method for preparing a high-entropy carbide-coated brake disc as described in claim 1, characterized in that, At least one of the following conditions a-e is met: a. The binder phase is a Ni-based alloy powder, an Fe-based alloy powder or a Co-based alloy powder; b. The D50 of the TiO2 powder, the Ta2O5 powder, the Nb2O5 powder and the W powder is 2-4 μm; c. The purity of the TiO2 powder, the Ta2O5 powder, the Nb2O5 powder and the W powder is all greater than or equal to 99.5%; d. The D50 particle size of the carbon black is D50=0.4-0.6 μm; e. The purity of the carbon black is greater than or equal to 99.9%.

4. The method for preparing a high-entropy carbide-coated brake disc as described in claim 3, characterized in that, At least one of the following conditions a-c is met: a. The Ni-based alloy powder comprises a nickel-copper high-temperature alloy powder, a nickel-based corrosion-resistant alloy powder and a nickel-based wear-resistant alloy powder; b. The Fe-based alloy powder is a martensitic alloy steel, a high-chromium cast iron, an austenitic manganese steel or a martensitic stainless steel; c. The Co-based alloy powder comprises a platinum-cobalt alloy, a samarium-cobalt alloy, a zirconium-cobalt alloy or a tungsten-cobalt alloy.

5. The method for preparing a high-entropy carbide-coated brake disc as described in claim 1, characterized in that, At least one of the following conditions a-c is met: a. The presser pressure of the pressing machine is 80-100 t, and the holding pressure time is 3-10 min; b. The sintering time is 4-6 h; c. The particle size of the sieving is 1-10 μm.

6. The method for preparing a high-entropy carbide-coated brake disc as described in claim 1, characterized in that, At least one of the following conditions a-b is met: a. The mass ratio of ethanol solution:sum of carbide powder and binder phase mass:PEG2000 in the slurry is 100:60~75:0.5~2; b. The method further comprises a step of glue grinding before the granulation.

7. The method for preparing a high-entropy carbide-coated brake disc as described in claim 1, characterized in that, At least one of the following conditions a~e is met: a. The substrate needs to be preheated, and the preheating temperature is 200~300℃; b. The laser cladding method is a synchronous laser cladding method; c. The laser cladding spot diameter is 2~4mm; d. The laser cladding powder feeding rate is 5~150g / min; e. The laser cladding defocusing amount is 0.5~1.5mm.

8. The high-entropy carbide coated brake disc prepared by the method of any one of claims 1~7.

9. The high entropy carbide coated brake disc of claim 8, wherein, At least one of the following conditions a~b is met: a. The substrate material is gray cast iron; b. The thickness of the high-entropy carbide coating is 0.2~2mm.

10. The high entropy carbide coated brake disc of claim 8, wherein, At least one of the following conditions a~c is met: a. The average microhardness of the high-entropy carbide coating is 410~1280 HV0.5; b. the high-entropy carbide coated brake disc has a friction coefficient of 0.27-0.35 mm 2 / N·m; c. the high-entropy carbide coated brake disc has a wear rate of 4 x 10 -4 ~100 x 10 -4 mm 3 / N·m.

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