Moalb / cu composite material and preparation method thereof

Abstract

The application discloses a MoAlB / Cu composite material and a preparation method thereof, and comprises the following steps: sequentially stacking a block MoAlB ceramic, a metal molybdenum foil and a metal Cu, and then performing warm and pressurized sintering to prepare an interface structure of MoAlB / Mo / Cu; and the molybdenum foil between the MoAlB ceramic and the metal Cu restrains the diffusion of Al atoms into the Cu matrix in the process of high-temperature and pressurized sintering of the MoAlB ceramic and the metal Cu, so that MoB compounds and Cu-Al alloys are formed, and meanwhile, a certain interface bonding strength is reserved between the MoAlB and the Cu. The copper layer guarantees the electric and thermal conductivity of the composite material, the MoAlB ceramic layer provides excellent high-temperature wear resistance and lubrication performance for the composite material, and the application has important significance for realizing the preparation of a copper-based composite material with high strength, high conductivity and high wear resistance.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of copper-based composite materials, and particularly relates to a MoAlB / Cu composite material and a preparation method thereof. BACKGROUND

[0002] With the progress of science and technology and the development of society, the performance of copper-based materials in the field of power electronics is required to be more stringent. In addition to ensuring good electrical conductivity, the copper-based materials also need to have excellent mechanical properties and wear resistance. At present, the widely used method is to prepare copper-based composite materials by adding ceramic particles or carbon nanotubes as reinforcing phases in the copper matrix to improve the wear resistance or mechanical properties of the copper-based materials.

[0003] MoAlB is a ceramic material with excellent performance, which has high hardness, good electrical conductivity and thermal conductivity, high-temperature oxidation resistance, and excellent high-temperature friction and wear behavior. It is considered as a very potential reinforcing phase of metal matrix composites.

[0004] It has been found in the current research that when MoAlB and copper are sintered at high temperature, Al atoms in MoAlB will diffuse into the Cu matrix. After the decomposition of MoAlB, MoB and Cu-Al alloy are generated at the ceramic-metal interface, which leads to the deterioration of the electrical conductivity and thermal conductivity of the composite material, and the loss of the research significance of MoAlB as a reinforcing phase to strengthen the wear resistance of the copper-based composite material. Therefore, a diffusion barrier material is usually added between MoAlB and copper to inhibit the diffusion behavior of Al atoms and improve the interface structure, so as to prepare a new type of copper-based composite material that meets the development needs of the times. SUMMARY

[0005] The technical problem to be solved by the application is to provide a MoAlB / Cu composite material and a preparation method thereof to solve the technical problem that Al atom diffusion occurs when MoAlB and copper are sintered at high temperature, which leads to the destruction of the ceramic phase and the deterioration of the performance of the composite material.

[0006] The application adopts the following technical scheme:

[0007] A MoAlB / Cu composite material preparation method, which comprises the following steps: placing MoAlB ceramic blocks, molybdenum foils and copper blocks in sequence and then performing warm and pressurized sintering treatment, introducing molybdenum foils at the interface between the copper blocks and the MoAlB ceramic blocks to form a MoAlB / Mo / Cu interface structure, and obtaining a MoAlB / Cu composite material.

[0008] Preferably, the size of the MoAlB ceramic blocks and the copper blocks is 25 mm in diameter and 3-5 mm in height.

[0009] Preferably, the thickness of the molybdenum foils is 5-15 μm.

[0010] Preferably, the warm and pressure sintering treatment is preceded by oil removal immersion washing of the MoAlB ceramic block, molybdenum foil and copper block, and drying after ultrasonic cleaning for standby.

[0011] More preferably, the oil removal immersion washing is completed in acetone.

[0012] More preferably, the ultrasonic cleaning time is 10-30 min.

[0013] Preferably, the warm and pressure sintering treatment is specifically:

[0014] heating at a heating rate of 5-10 ℃ / min to 300-500 ℃ and holding for 1-2 h; and continuously heating to 1000-1050 ℃ and holding for 2-10 h.

[0015] More preferably, the pressure is maintained at 15-25 MPa throughout the warm and pressure sintering treatment.

[0016] Preferably, argon is used as the protective atmosphere throughout the warm and pressure sintering treatment.

[0017] Another technical solution of the present application is a MoAlB / Cu composite material, which has a Vickers hardness of 300-350 HV, a wear rate of 0.5-0.7*10 -4 mm 3 / (N*m), and a friction coefficient of 0.18-0.2.

[0018] Compared with the prior art, the present application has at least the following beneficial effects:

[0019] A MoAlB / Cu composite material preparation method, by adding a molybdenum foil between copper and MoAlB, can solve the problem of decomposition of the ceramic reinforcing phase caused by the diffusion of aluminum atoms in MoAlB ceramic into the copper matrix during the hot-pressing sintering process. At the same time, the addition of the molybdenum foil further enhances the interfacial bonding of the composite material and improves the lubrication performance of the composite material, enabling the preparation of high-performance copper-based composite materials with excellent electrical conductivity, thermal conductivity, wear resistance and lubrication performance, meeting the new requirements of the new era for copper-based composite materials, providing a new idea and method for inhibiting the reaction between the ceramic reinforcing phase and the metal matrix at high temperatures and preparing feasible high-performance copper-based composite materials.

[0020] Further, the MoAlB ceramic block and the copper block used have a size of 25 mm in diameter and 3-5 mm in height. The thickness of the copper block and the ceramic block can be selected according to performance requirements to achieve the purpose of preparing high-performance copper-based composite materials with excellent electrical conductivity, wear resistance and lubrication.

[0021] Further, the thickness of the molybdenum foil is 5-15 microns, and the thickness of the molybdenum foil can be selected according to the experimental design requirements, but the molybdenum foil cannot be too thin to prevent the thin molybdenum foil from achieving the effect of inhibiting the diffusion of aluminum atoms.

[0022] Further, the ceramic block, the molybdenum foil and the copper block are baked after oil removal immersion and ultrasonic cleaning to remove the impurities and oil stains on the surface, eliminate the experimental variables, and avoid the introduction of impurities at the interface in the subsequent hot-pressing sintering process to reduce the interface bonding strength.

[0023] Further, the hot-pressing sintering process is to heat to 300-500 DEG C in a hot-pressing furnace for 1-2 hours, continue to heat to 1000-1050 DEG C for 2-10 hours, and the heating rate is 5-10 DEG C / min, which can ensure that the material is uniformly heated and is beneficial to obtain good interface bonding.

[0024] Further, the whole process is pressurized at 15-25 MPa, which can ensure that the material is uniformly heated and is beneficial to obtain good interface bonding.

[0025] Further, the hot-pressing sintering process uses argon as a protective atmosphere, and a customized graphite mold is used as a sintering mold, and the protective atmosphere of argon can avoid the oxidation of the material in the sintering process.

[0026] The MoAlB / Cu composite material is prepared by the hot-pressing sintering process, and the molybdenum foil is introduced as a diffusion barrier between MoAlB and copper to inhibit the severe interface reaction between the ceramic block and the metal matrix at high temperature, so that the high-performance copper-based composite material with excellent electrical conductivity, wear resistance and lubricity can be obtained, the completeness of the properties of the ceramic block and the metal matrix is reserved, and a feasible preparation method is provided for the large-scale promotion of the material in the fields of power electronics and rail transportation.

[0027] In summary, the MoAlB / Cu composite material prepared by the application has good interface and reinforcing effect, and the comprehensive performance of the copper-based composite material can be improved.

[0028] The technical solutions of the application will be further described in detail below with reference to the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is a preparation process schematic diagram;

[0030] Figure 2 It is a sample microstructure schematic diagram;

[0031] Figure 3 It is a friction coefficient curve of the MoAlB / Cu composite material prepared by the application and a friction time relationship diagram. DETAILED DESCRIPTION

[0032] The technical solutions of the present application will be described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0033] In the present application, all the embodiments and preferred embodiments mentioned in the present application can be combined to form new technical solutions, if not otherwise specified.

[0034] In the present application, all the technical features and preferred features mentioned in the present application can be combined to form new technical solutions, if not otherwise specified.

[0035] In the present application, the percentage (%) or the part refers to the percentage by weight or the weight part of the composition, if not otherwise specified.

[0036] In the present application, all the components or preferred components mentioned in the present application can be combined to form new technical solutions, if not otherwise specified.

[0037] In the present application, unless otherwise specified, the numerical range "a~b" represents a shorthand notation for any real number combination between a and b, wherein a and b are both real numbers. For example, the numerical range "6~22" represents that all the real numbers between "6~22" have been listed herein, and "6~22" is only a shorthand notation for these numerical combinations.

[0038] The lower limit and the upper limit of the range disclosed in the present application can be one or more lower limits and one or more upper limits, respectively.

[0039] In the present application, the term "and / or" used herein means any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0040] In the present application, unless otherwise specified, each reaction or operation step can be carried out sequentially or according to the sequence. Preferably, the reaction method herein is carried out sequentially.

[0041] Unless otherwise specified, the professional and scientific terms used herein have the same meaning as those familiar to those skilled in the art. In addition, any method or material similar or equivalent to the described content can also be applied in the present application.

[0042] The application provides a MoAlB / Cu composite material and a preparation method thereof. The copper-based composite material with excellent electric conductivity, heat conductivity, wear resistance and lubrication performance can be obtained by adding a molybdenum foil between MoAlB and copper and then adopting a hot-pressing sintering preparation process. The reaction of MoAlB and copper at high temperature is inhibited by adding the molybdenum foil, the decomposition of MoAlB and copper into MoB and copper-aluminum alloy caused by the interface diffusion of Al atoms is avoided, a good interface and reinforcing effect are obtained, the comprehensive performance of the copper-based composite material is improved, and a feasible preparation method is provided for the large-scale promotion of the MoAlB / Cu composite material in the field of power electronics.

[0043] Referring to Figure 1 The application provides a preparation method of a MoAlB / Cu composite material, which comprises the following steps:

[0044] S1, preparing raw materials, including MoAlB ceramic blocks, copper blocks and a molybdenum foil;

[0045] The mass range interval of the MoAlB ceramic blocks is 9-15 g, the mass range interval of the copper blocks is 13-22 g, and the mass range interval of the molybdenum foil is 25-75 mg.

[0046] The size of the MoAlB ceramic blocks and the copper blocks is 25 mm in diameter and 3-5 mm in height; the thickness of the MoAlB ceramic blocks and the copper blocks is selected according to performance requirements, and the thickness of the molybdenum foil is 5-15 microns.

[0047] S2, the MoAlB ceramic blocks, the copper blocks and the molybdenum foil obtained in step S1 are immersed in acetone for oil removal and washing, and then are dried after being ultrasonically treated for 10-30 min;

[0048] S3, the MoAlB ceramic blocks, the molybdenum foil and the copper blocks obtained in step S2 are sequentially stacked and placed for warm-pressing sintering treatment, the molybdenum foil is introduced at the interface between the copper blocks and the MoAlB ceramic blocks to form a MoAlB / Mo / Cu interface structure, and a MoAlB / Cu composite material is obtained by hot-pressing sintering.

[0049] The temperature of the warm-pressing sintering treatment is 300-500 DEG C, the holding time is 1-2 h, the temperature is continuously increased to 1000-1050 DEG C, the holding time is 2-10 h, and the temperature increasing rate is controlled to be 5-10 DEG C / min, and the pressure is controlled to be 15-25 MPa throughout the whole process.

[0050] Argon is used as a protective atmosphere throughout the whole process of the warm-pressing sintering treatment, and a customized graphite mold is used as a sintering mold.

[0051] The MoAlB / Cu composite material of the application utilizes the molybdenum foil between the MoAlB ceramic block and the copper block to inhibit the diffusion of Al atoms into the Cu matrix during the high-temperature press sintering process of the MoAlB ceramic block and the copper block to form MoB compounds and Cu-Al alloys, and meanwhile, a certain interface bonding strength is retained between the MoAlB ceramic block and the copper block; wherein the copper layer ensures the electric and thermal conductivity of the composite material, and the MoAlB ceramic layer provides excellent high-temperature wear resistance and lubrication performance for the composite material, which is of great significance to the preparation of copper-based composite materials with high strength, high conductivity and high wear resistance.

[0052] The performance of the prepared MoAlB / Cu composite material changes with the addition ratio of MoAlB in the copper matrix, and in general, the mechanical properties of the composite material are improved compared with pure copper, and the composite material has excellent wear resistance and lubrication performance; within the addition content range of MoAlB, the Vickers hardness of the MoAlB / Cu composite material prepared by the application ranges from 300 to 350 HV, the wear rate ranges from 0.5 to 0.7*10 -4 mm 3 / (N·m), and the friction coefficient ranges from 0.18 to 0.2.

[0053] To make the purpose, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below in combination with the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. The components of the embodiments of the application described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. All other embodiments obtained by those of ordinary skill in the art without creative labor based on the embodiments in the application belong to the scope of protection of the application.

[0054] Embodiment 1

[0055] 1. The raw materials for sintering are MoAlB ceramic blocks, copper blocks and molybdenum foils, and the adopted process is hot-press sintering. The size of the ceramic block and the copper block is 25mm in diameter and 3mm in height. The thickness of the copper block and the ceramic block can be selected according to the performance requirements, and the thickness of the molybdenum foil is 5μm.

[0056] 2. The ceramic block, the copper block and the molybdenum foil are subjected to oil removal immersion washing with acetone and ultrasonic treatment for 10min, and then are dried.

[0057] 3. The hot-pressing sintering process is to heat to 300℃ in a hot-pressing furnace for 2h, continue to heat to 1000℃ for 10h, the heating rate is 5℃ / min, and the whole process is under 15MPa pressure.

[0058] The composite material prepared by the preparation process of Example 1 has high mechanical strength and wear resistance, relatively poor electrical conductivity, and part of MoB and copper-aluminum alloy is still generated at the interface bonding, which is suitable for use in working conditions with high requirements for mechanical properties and friction properties and low requirements for electrical conductivity.

[0059] Example 2

[0060] 1. The raw materials for sintering are MoAlB ceramic blocks, copper blocks and molybdenum foils, the process adopted is hot-pressing sintering, the size of the ceramic blocks and copper blocks is 25mm in diameter and 3mm in height. The thickness of the copper blocks and ceramic blocks can be selected according to performance requirements, and the thickness of the molybdenum foil is 10μm.

[0061] 2. The ceramic blocks, copper blocks and molybdenum foils are immersed in acetone for oil removal and washing, and then dried after ultrasonic treatment for 20min.

[0062] 3. The hot-pressing sintering process is to heat to 400℃ in a hot-pressing furnace for 2h, continue to heat to 1030℃ for 10h, the heating rate is 8℃ / min, and the whole process is under 20MPa pressure.

[0063] The composite material prepared by the preparation process of Example 2 has high mechanical strength and wear resistance, good electrical conductivity, good interface bonding between the ceramic blocks and the molybdenum foils and between the molybdenum foils and the copper blocks, and is suitable for use in working conditions with balanced requirements for mechanical properties, friction properties and electrical conductivity.

[0064] Example 3

[0065] 1. The raw materials for sintering are MoAlB ceramic blocks, copper blocks and molybdenum foils, the process adopted is hot-pressing sintering, the size of the ceramic blocks and copper blocks is 25mm in diameter and 3mm in height. The thickness of the copper blocks and ceramic blocks can be selected according to performance requirements, and the thickness of the molybdenum foil is 15μm.

[0066] 2. The ceramic blocks, copper blocks and molybdenum foils are immersed in acetone for oil removal and washing, and then dried after ultrasonic treatment for 30min.

[0067] 3. The hot-pressing sintering process is to heat to 500℃ in a hot-pressing furnace for 2h, continue to heat to 1050℃ for 10h, the heating rate is 10℃ / min, and the whole process is under 25MPa pressure.

[0068] The composite material prepared by the preparation process of Example 3 has poor mechanical strength and wear resistance, good electrical conductivity, and poor interface bonding between the ceramic block and the molybdenum foil and the molybdenum foil and the copper block. The excessively thick molybdenum foil is difficult to melt at high temperatures to react with the ceramic block and the copper block, and is suitable for use in working conditions with low requirements for mechanical properties and friction properties and strict requirements for electrical conductivity.

[0069] Comparative Example 1

[0070] In the comparative example, no molybdenum foil is used as a diffusion barrier for the MoAlB-Cu laminated composite material. The material has a compact structure, strong interface bonding, and a clear diffusion layer between the ceramic block and the copper block. The main components of the diffusion layer are MoB and copper-aluminum alloy. The presence of the diffusion layer reduces the electrical conductivity of the composite material, but the presence of hard MoB makes the composite material have strong wear resistance.

[0071] Referring to Figure 1 The method of the present application includes three steps of raw material preparation, oil removal and cleaning, and hot pressing and sintering, and can prepare a MoAlB-Cu composite material with a molybdenum foil as a diffusion barrier, and can solve the problem of Al atom diffusion into the copper matrix during high-temperature sintering of MoAlB and copper to form MoB and copper-aluminum alloy.

[0072] Referring to Figure 2 The MoAlB-Cu laminated composite material without adding a molybdenum foil as a diffusion barrier has a clear diffusion interface layer, and the MoAlB-Cu laminated composite material with a molybdenum foil as a diffusion barrier has no clear diffusion interface layer and has good interface bonding strength, which is beneficial to maintaining excellent electrical conductivity of the composite material while maintaining wear-reducing lubrication performance and good mechanical properties.

[0073] Referring to Figure 3 The mass fraction ratio of the MoAlB ceramic block and the copper block is 1:1, and the corresponding MoAlB / Cu composite material is prepared according to the process flow described in the patent, and then the friction and wear experiment is carried out. The figure is the result of the friction and wear experiment, in which the vertical axis COF represents the friction coefficient and the horizontal axis represents the friction time.

[0074] It is concluded that from the figure, as the friction time continues, the friction coefficient of the composite material stabilizes at about 0.18, and compared with the stable friction coefficient of pure copper 0.75, the friction coefficient of the prepared composite material is greatly reduced, which indicates that the prepared composite material has excellent lubrication performance.

[0075] In summary, the MoAlB / Cu composite material and the preparation method thereof can effectively avoid defects in the preparation process of the copper-based composite material, and can prepare a MoAlB / Cu composite material diffusion barrier interface, solve the problem of decomposition of the ceramic reinforcing phase caused by the diffusion of aluminum atoms in the MoAlB ceramic to the copper matrix during the hot-pressing sintering process, obtain good interface and reinforcing effect, and improve the comprehensive performance of the copper-based composite material.

[0076] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for producing a MoAlB / Cu composite material, characterized by, MoAlB ceramic bulk, molybdenum foil and copper bulk are placed in sequence and then subjected to warm and pressure sintering treatment, the thickness of the molybdenum foil is 10 μm, the molybdenum foil is introduced at the interface between the copper bulk and the MoAlB ceramic bulk to form the interface structure of MoAlB / Mo / Cu, and the MoAlB / Cu composite material is obtained.

2. The MoAlB / Cu composite material production method according to claim 1, wherein The size of the MoAlB ceramic bulk and the copper bulk is 25 mm in diameter and 3-5 mm in height.

3. The MoAlB / Cu composite material production method according to claim 1, wherein The warm and pressure sintering treatment is as follows: the MoAlB ceramic bulk, the molybdenum foil and the copper bulk are subjected to oil removal immersion washing, ultrasonic cleaning and drying.

4. The MoAlB / Cu composite material production method according to claim 3, wherein The oil removal immersion washing is completed in acetone.

5. The MoAlB / Cu composite material production method according to claim 3, wherein The ultrasonic cleaning is performed for 10-30 min.

6. The MoAlB / Cu composite material production method according to claim 1, wherein The warm and pressure sintering treatment is as follows: the temperature is raised to 300-500 ℃ at a temperature raising rate of 5-10 ℃ / min and is kept for 1-2 h; the temperature is continuously raised to 1000-1050 ℃ and is kept for 2-10 h.

7. The MoAlB / Cu composite material production method according to claim 6, wherein During the warm and pressure sintering treatment, the pressure is kept at 15-25 MPa.

8. The MoAlB / Cu composite material production method according to claim 1, wherein During the warm and pressure sintering treatment, argon is used as the protective atmosphere.

9. MoAlB / Cu composite material prepared according to the method of any one of claims 1 to 8, characterized in that The Vickers hardness is 300-350 HV, the wear rate is 0.5-0.7*10 -4 mm 3 / (N*m), and the friction coefficient is 0.18-0.2.

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