A diamond metal composite material and its preparation method

Abstract

This invention discloses a diamond metal composite material and its preparation method, relating to the field of composite material technology. The material includes a metal matrix and a diamond composite. The diamond composite comprises 60%-75% by volume of the total composite material. The diamond composite includes diamond particles and a gradient functional transition layer composited on the surface of the diamond particles. The metal matrix is ​​composed of the following components by mass percentage: Ag 1-3wt%, In 0.5-1.5wt%, rare earth elements 0.1-0.2wt%, B 0.001-0.01wt%, Ta 0.01-0.03wt%, Zr 0.05-0.1wt%, with the balance being Cu. This composite material exhibits high thermal conductivity, excellent high-temperature stability, and superior wear resistance.

Description

Technical Field

[0001] This invention relates to the field of composite material technology, and in particular to a diamond metal composite material and its preparation method. Background Technology

[0002] In high-end manufacturing fields such as 5G communications, new energy vehicles, and aerospace, stringent requirements are placed on the heat dissipation efficiency and structural strength of core components. Traditional metal heat dissipation materials can no longer meet the heat dissipation needs of these components. Metal matrix composites, which combine the mechanical properties of metals with the high thermal conductivity of reinforcements, are gradually replacing traditional heat dissipation materials.

[0003] Diamond / metal composites are a common type of metal matrix composite, also known as diamond particle-reinforced metal matrix composites. They are particle-reinforced metal matrix composites formed by uniformly dispersing diamond particles within a metal. This composite combines the advantages of both metal and diamond, theoretically achieving superior thermal conductivity while maintaining an ideal coefficient of thermal expansion and low density. However, currently prepared diamond metal matrix composites exhibit low thermal conductivity, sometimes even lower than that of the metal matrix. This is primarily due to the poor wettability between the metal and diamond, resulting in a weak bond and numerous structural defects and voids at the interface. This leads to electron and phonon scattering at the interface, creating high interfacial thermal resistance and limiting the improvement of the composite's thermal conductivity. To address this issue, current methods mainly employ diamond surface modification and metal matrix alloying. However, these methods often suffer from unstable results, complex processes, high costs, and negative impacts on the composite's thermal conductivity.

[0004] To address the aforementioned issues, Chinese invention patent CN105986158B discloses a diamond-metal composite material. Specifically, the composite material comprises a metal matrix and a diamond composite, wherein the diamond composite comprises diamond particles and a surface coating bonded to the surface of the diamond particles. This invention also discloses a method for preparing the composite material and its applications. This method is simple, effective, and low-cost, yielding a composite material with excellent performance, showing great market potential in the field of electronic packaging heat sinks. However, its high-temperature stability and wear resistance still need further improvement.

[0005] It is evident that developing a diamond metal composite material with high thermal conductivity, excellent high-temperature stability and wear resistance, and its preparation method, has significant practical importance and market demand. Summary of the Invention

[0006] The main objective of this invention is to provide a diamond metal composite material with high thermal conductivity, excellent high-temperature stability and wear resistance, and a method for preparing the same.

[0007] To achieve the above objectives, the present invention provides a diamond metal composite material, comprising a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 60%-75% based on the total volume of the composite material; the diamond composite comprises diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 1-3wt%, In 0.5-1.5wt%, rare earth elements 0.1-0.2wt%, B 0.001-0.01wt%, Ta 0.01-0.03wt%, Zr 0.05-0.1wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 50-100nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 200-500nm; and the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 1-3μm.

[0008] Preferably, the rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:(0.8-1.2):(0.3-0.5).

[0009] Preferably, the method for preparing the diamond composite includes the following steps:

[0010] Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 500-800W to form a nanoscale pit structure on the surface.

[0011] Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere;

[0012] Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition;

[0013] Step D4, outer alloying treatment: Immerse the deposited diamond particles into Cu-Ti-Zr molten alloy and impregnate for 10-20 minutes under ultrasonic vibration assistance to form an outer alloy layer.

[0014] Preferably, the average particle size of the diamond particles in step D1 is 20-50 μm.

[0015] Preferably, the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1.

[0016] Preferably, the etching time in step D1 is 30-60 seconds.

[0017] Preferably, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas in step D2 is 10:1.

[0018] Preferably, the deposition temperature in step D2 is 500-600℃, the bias voltage is -100 to -150V, and the deposition rate is 5-10nm / min.

[0019] Preferably, the deposition temperature in step D3 is 600℃, the bias voltage is -80 to -120V, and it is divided into three stages. The initial stage lasts for 1-10 minutes, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 10-40 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 40-60 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

[0020] Preferably, the Cu-Ti-Zr molten alloy in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance Cu.

[0021] Another object of the present invention is to provide a method for preparing the diamond metal composite material, comprising the following steps: mixing metal matrix powder and diamond composite material evenly, and then placing the mixture in a magnetic field oscillator under a vacuum of 10... - 2 Mix the material with a vibratory magnetic field for 15-25 minutes. Then, slowly pour the mixed material into a graphite mold using a vibration filling method. After filling, place a graphite pressure head above the material, controlling the gap between the pressure head and the inner wall of the mold to be 0.1-0.2 mm. Then, place the graphite mold containing the material into a spark plasma sintering (SPCS) machine for SPCS. After SPCS, wait for the mold to cool to room temperature, remove the pre-sintered blank, and then perform microwave-strengthened sintering to obtain a diamond metal composite material.

[0022] Preferably, the frequency of the vibration magnetic field-assisted mixing is 60Hz and the power is 1200W.

[0023] Preferably, the specific parameters of the discharge plasma sintering are: sintering temperature 645-655℃, heating rate 48-52℃ / min; applied pressure 28-32MPa, pressure maintained at constant pressure; sintering time 5-8min; plasma current 8000A.

[0024] Preferably, the specific parameters for microwave-enhanced sintering are: sintering temperature 845-855℃, heating rate 28-32℃ / min; applied pressure 38-42MPa; sintering time 8-12min.

[0025] Due to the application of the above technical solution, the present invention has the following beneficial effects:

[0026] (1) The diamond metal composite material disclosed in this invention has a simple preparation method, is easy to industrialize, has high preparation efficiency, low dependence on equipment, and has high application value.

[0027] (2) The diamond metal composite material disclosed in this invention includes a metal matrix and a diamond composite. The volume percentage of the diamond composite is 60%-75% based on the total volume of the composite material. The diamond composite contains diamond particles and a gradient functional transition layer composited on the surface of the diamond particles. The metal matrix is ​​made of the following components in mass percentage: Ag 1-3wt%, In 0.5-1.5wt%, rare earth elements 0.1-0.2wt%, B 0.001-0.01wt%, Ta 0.01-0.03wt%, Zr 0.05-0.1wt%, with the balance being Cu. The gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outward. The inner layer is a TiC layer with a thickness of 50-100nm. The intermediate layer is a Ti-Zr solid solution layer with a thickness of 200-500nm. The outer layer is a Cu-Ti-Zr alloy layer with a thickness of 1-3μm. Through the design of the above components and structure, the interaction between the components and structure can be better utilized, giving the composite material advantages such as high thermal conductivity, high temperature stability and excellent wear resistance.

[0028] (3) The diamond metal composite material disclosed in this invention is made of the following components in mass percentage: Ag 1-3wt%, In 0.5-1.5wt%, rare earth elements 0.1-0.2wt%, B 0.001-0.01wt%, Ta 0.01-0.03wt%, Zr 0.05-0.1wt%, with the balance being Cu; Ag forms a nano-precipitate phase at the grain boundary, inhibiting the diffusion of Cu atoms; In forms a high-temperature stable phase LaIn3 with rare earth elements (such as Y and La), pinning the grain boundary to prevent the formation of the brittle phase Cu4Ti; B preferentially adsorbs at the defects at the diamond / transition layer interface, forming BC bonds to enhance the interfacial bonding force; Ta and Zr work together to form a TaZr2 intermetallic compound at the interface, improving wear resistance; Zr forms a Cu5Zr precipitate phase with Cu, which, together with the fine grain strengthening of Ag, significantly improves the room temperature hardness of the metal matrix while maintaining high thermal conductivity. The precise proportion of multiple elements (with the content of each element controlled within a specific range to avoid excess or deficiency) has achieved a simultaneous improvement in thermal conductivity, strength, and high-temperature stability, breaking through the performance ceiling of single-element alloying.

[0029] (4) The diamond metal composite material disclosed in this invention has a semi-coherent interface between the inner TiC layer of the gradient functional transition layer and diamond, which reduces the basic thermal resistance through "phonon matching"; the atomic radius of Zr in the middle Ti-Zr solid solution is larger than that of Ti, and a "stress buffer zone" is formed from diamond to the outer layer through "gradient doping", which reduces the residual stress at the interface and avoids crack initiation; the outer Cu-Ti-Zr alloy forms a "composition gradient" with Cu and Zr elements in the metal matrix, and the interface metallurgical bonding is achieved through diffusion welding, eliminating the thermal resistance abrupt change caused by traditional physical bonding. The synergistic effect of the three-layer structure optimizes the interface thermal resistance and stress at the same time, solving the bottleneck of the prior art where "thermal conductivity and structural stability" cannot be achieved simultaneously.

[0030] (5) The diamond metal composite material disclosed in this invention has a high degree of matching between the outer Cu-Ti-Zr alloy layer and the metal matrix composition. During the sintering process, it can act as a "liquid phase channel" to promote the penetration of the metal matrix into the diamond gaps and solve the wetting problem at high volume fractions. In the metal matrix, Ag lowers the alloy melting point, and In further optimizes the melt viscosity, so that the metal matrix can still achieve complete filling at a diamond volume fraction of 60%-75%. This design breaks through the contradiction between "high volume fraction and densification" in traditional composite materials and lays the foundation for ultra-high thermal conductivity. The TiC inner layer forms a semi-coherent interface with diamond. The interface stress is relieved by gradient Zr element doping (intermediate layer), and the Ti3Cu4 particles in the outer Cu-Ti-Zr alloy achieve electron-phonon synergistic thermal conduction. The vibration magnetic field-assisted mixing can effectively improve the particle dispersion uniformity. The two-step sintering method uses SPS low-temperature pre-sintering to suppress diamond thermal damage (<800℃) and microwave sintering to shorten the cycle and reduce energy consumption. Detailed Implementation

[0031] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art. Example 1

[0032] A diamond-metal composite material includes a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 60% based on the total volume of the composite material; the diamond composite comprises diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 1wt%, In 0.5wt%, rare earth elements 0.1wt%, B 0.001wt%, Ta 0.01wt%, Zr 0.05wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 50nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 200nm; the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 1μm; the rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:0.8:0.3.

[0033] The method for preparing the diamond composite includes the following steps:

[0034] Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 500W to form a nanoscale pit structure on the surface.

[0035] Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere;

[0036] Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition;

[0037] Step D4, outer alloying treatment: The deposited diamond particles are immersed in Cu-Ti-Zr molten alloy and impregnated for 10 minutes under ultrasonic vibration to form an outer alloy layer.

[0038] The average particle size of the diamond particles in step D1 is 20 μm; the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1; and the etching time in step D1 is 30 s.

[0039] In step D2, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas is 10:1; the deposition temperature in step D2 is 500℃, the bias voltage is -100V, and the deposition rate is 5nm / min.

[0040] The deposition temperature in step D3 is 600℃, the bias voltage is -80V, and it is divided into three stages. The initial stage lasts for 1 minute, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 10 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 40 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

[0041] The Cu-Ti-Zr molten alloy described in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance being Cu.

[0042] A method for preparing the diamond metal composite material includes the following steps: mixing metal matrix powder and diamond composite material evenly, then placing the mixture in a magnetic field oscillator under a vacuum of 10... -2 Mix the material with a vibratory magnetic field for 15 minutes. Then, slowly pour the mixed material into a graphite mold using a vibration filling method. After filling, place a graphite pressure head above the material, controlling the gap between the pressure head and the inner wall of the mold to be 0.1 mm. Then, place the graphite mold containing the material into a discharge plasma sintering (SPCS) device for SPCS. After SPCS, wait for the mold to cool to room temperature, remove the pre-sintered blank, and then perform microwave-strengthened sintering to obtain a diamond metal composite material.

[0043] The frequency of the vibration magnetic field-assisted mixing is 60 Hz, and the power is 1200 W. The specific parameters of the discharge plasma sintering are: sintering temperature 645℃, heating rate 48℃ / min; applied pressure 28MPa, pressure maintained at constant pressure; sintering time 5 min; plasma current 8000A. The specific parameters of the microwave-enhanced sintering are: sintering temperature 845℃, heating rate 28℃ / min; applied pressure 38MPa; sintering time 8 min. Example 2

[0044] A diamond-metal composite material includes a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 65% based on the total volume of the composite material; the diamond composite comprises diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 1.5wt%, In 0.8wt%, rare earth elements 0.13wt%, B 0.003wt%, Ta 0.015wt%, Zr 0.06wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 60nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 300nm; the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 1.5μm; the rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:0.9:0.35.

[0045] The method for preparing the diamond composite includes the following steps:

[0046] Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 600W to form a nanoscale pit structure on the surface.

[0047] Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere;

[0048] Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition;

[0049] Step D4, outer alloying treatment: The deposited diamond particles are immersed in Cu-Ti-Zr molten alloy and impregnated for 13 minutes under ultrasonic vibration to form an outer alloy layer.

[0050] The average particle size of the diamond particles in step D1 is 25 μm; the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1; and the etching time in step D1 is 40 s.

[0051] In step D2, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas is 10:1; the deposition temperature in step D2 is 530℃, the bias voltage is -120V, and the deposition rate is 6nm / min.

[0052] The deposition temperature in step D3 is 600℃, the bias voltage is -90V, and it is divided into three stages. The initial stage lasts for 4 minutes, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 20 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 45 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

[0053] The Cu-Ti-Zr molten alloy described in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance being Cu.

[0054] A method for preparing the diamond metal composite material includes the following steps: mixing metal matrix powder and diamond composite material evenly, then placing the mixture in a magnetic field oscillator under a vacuum of 10... -2 The material was mixed with a vibratory magnetic field for 18 minutes. Then, the mixed material was slowly poured into a graphite mold using a vibration filling method. After filling, a graphite pressure head was placed above the material, with the gap between the pressure head and the inner wall of the mold controlled at 0.13 mm. The graphite mold containing the material was then placed into a spark plasma sintering (SPS) equipment for SPS. After SPS, the mold was allowed to cool to room temperature, the pre-sintered blank was removed, and then microwave-strengthened sintering was performed to obtain a diamond metal composite material.

[0055] The frequency of the vibration magnetic field-assisted mixing is 60 Hz, and the power is 1200 W. The specific parameters of the discharge plasma sintering are: sintering temperature 648℃, heating rate 49℃ / min; applied pressure 29 MPa, pressure maintained at constant pressure; sintering time 6 min; plasma current 8000 A. The specific parameters of the microwave-enhanced sintering are: sintering temperature 848℃, heating rate 29℃ / min; applied pressure 39 MPa; sintering time 9 min. Example 3

[0056] A diamond-metal composite material includes a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 68% based on the total volume of the composite material; the diamond composite comprises diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 2wt%, In 1wt%, rare earth elements 0.15wt%, B 0.006wt%, Ta 0.02wt%, Zr 0.07wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 80nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 350nm; the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 2μm; the rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:1:0.4.

[0057] The method for preparing the diamond composite includes the following steps:

[0058] Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 650W to form a nanoscale pit structure on the surface.

[0059] Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere;

[0060] Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition;

[0061] Step D4, outer alloying treatment: The deposited diamond particles are immersed in Cu-Ti-Zr molten alloy and impregnated for 15 minutes under ultrasonic vibration to form an outer alloy layer.

[0062] The average particle size of the diamond particles in step D1 is 35 μm; the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1; and the etching time in step D1 is 45 s.

[0063] In step D2, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas is 10:1; the deposition temperature in step D2 is 550℃, the bias voltage is -130V, and the deposition rate is 7.5nm / min.

[0064] The deposition temperature in step D3 is 600℃, the bias voltage is -100V, and it is divided into three stages. The initial stage lasts for 6 minutes, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 25 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 50 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

[0065] The Cu-Ti-Zr molten alloy described in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance being Cu.

[0066] A method for preparing the diamond metal composite material includes the following steps: mixing metal matrix powder and diamond composite material evenly, then placing the mixture in a magnetic field oscillator under a vacuum of 10... -2 Mix the material with a vibratory magnetic field for 20 minutes. Then, slowly pour the mixed material into a graphite mold using a vibration filling method. After filling, place a graphite pressure head above the material, controlling the gap between the pressure head and the inner wall of the mold to be 0.15 mm. Then, place the graphite mold containing the material into a spark plasma sintering (SPCS) device for SPCS. After SPCS, wait for the mold to cool to room temperature, remove the pre-sintered blank, and then perform microwave-strengthened sintering to obtain a diamond metal composite material.

[0067] The frequency of the vibration magnetic field-assisted mixing is 60 Hz, and the power is 1200 W. The specific parameters of the discharge plasma sintering are: sintering temperature 650℃, heating rate 50℃ / min; applied pressure 30 MPa, pressure maintained at constant pressure; sintering time 6.5 min; plasma current 8000 A. The specific parameters of the microwave-enhanced sintering are: sintering temperature 850℃, heating rate 30℃ / min; applied pressure 40 MPa; sintering time 10 min. Example 4

[0068] A diamond-metal composite material includes a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 73% based on the total volume of the composite material; the diamond composite comprises diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 2.5wt%, In 1.3wt%, rare earth elements 0.18wt%, B 0.009wt%, Ta 0.025wt%, Zr 0.09wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 90nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 450nm; the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 2.5μm; the rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:1.1:0.45.

[0069] The method for preparing the diamond composite includes the following steps:

[0070] Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 750W to form a nanoscale pit structure on the surface.

[0071] Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere;

[0072] Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition;

[0073] Step D4, outer alloying treatment: The deposited diamond particles are immersed in Cu-Ti-Zr molten alloy and impregnated for 18 minutes under ultrasonic vibration to form an outer alloy layer.

[0074] The average particle size of the diamond particles in step D1 is 45 μm; the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1; and the etching time in step D1 is 55 s.

[0075] In step D2, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas is 10:1; the deposition temperature in step D2 is 590℃, the bias voltage is -140V, and the deposition rate is 9nm / min.

[0076] The deposition temperature in step D3 is 600℃, the bias voltage is -110V, and it is divided into three stages. The initial stage lasts for 8 minutes, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 10-40 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 40-60 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

[0077] The Cu-Ti-Zr molten alloy described in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance being Cu.

[0078] A method for preparing the diamond metal composite material includes the following steps: mixing metal matrix powder and diamond composite material evenly, then placing the mixture in a magnetic field oscillator under a vacuum of 10... -2 The material was mixed with a vibratory magnetic field for 23 minutes under Pa. Then, the mixed material was slowly poured into a graphite mold using a vibration filling method. After filling, a graphite pressure head was placed above the material, with the gap between the pressure head and the inner wall of the mold controlled at 0.18 mm. The graphite mold containing the material was then placed into a spark plasma sintering (SPS) equipment for SPS. After SPS, the mold was allowed to cool to room temperature, the pre-sintered blank was removed, and then microwave-strengthened sintering was performed to obtain a diamond metal composite material.

[0079] The frequency of the vibration magnetic field-assisted mixing is 60 Hz, and the power is 1200 W. The specific parameters of the discharge plasma sintering are: sintering temperature 653℃, heating rate 51℃ / min; applied pressure 31 MPa, pressure held at constant pressure; sintering time 7.5 min; plasma current 8000 A. The specific parameters of the microwave-enhanced sintering are: sintering temperature 853℃, heating rate 31℃ / min; applied pressure 41 MPa; sintering time 11 min. Example 5

[0080] A diamond-metal composite material includes a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 75% based on the total volume of the composite material; the diamond composite comprises diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 3wt%, In 1.5wt%, rare earth elements 0.2wt%, B 0.01wt%, Ta 0.03wt%, Zr 0.1wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 100nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 500nm; the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 3μm; the rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:1.2:0.5.

[0081] The method for preparing the diamond composite includes the following steps:

[0082] Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 800W to form a nanoscale pit structure on the surface.

[0083] Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere;

[0084] Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition;

[0085] Step D4, outer alloying treatment: The deposited diamond particles are immersed in Cu-Ti-Zr molten alloy and impregnated for 20 minutes under ultrasonic vibration to form an outer alloy layer.

[0086] The average particle size of the diamond particles in step D1 is 50 μm; the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1; and the etching time in step D1 is 60 s.

[0087] In step D2, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas is 10:1; the deposition temperature in step D2 is 600℃, the bias voltage is -150V, and the deposition rate is 10nm / min.

[0088] The deposition temperature in step D3 is 600℃, the bias voltage is -120V, and it is divided into three stages. The initial stage lasts for 10 minutes, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 40 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 60 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

[0089] The Cu-Ti-Zr molten alloy described in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance being Cu.

[0090] A method for preparing the diamond metal composite material includes the following steps: mixing metal matrix powder and diamond composite material evenly, then placing the mixture in a magnetic field oscillator under a vacuum of 10... -2 The material was mixed with a vibratory magnetic field for 25 minutes. Then, the mixed material was slowly poured into a graphite mold using a vibration filling method. After filling, a graphite pressure head was placed above the material, with the gap between the pressure head and the inner wall of the mold controlled at 0.2 mm. The graphite mold containing the material was then placed into a spark plasma sintering (SPS) device for SPS. After SPS, the mold was allowed to cool to room temperature. The pre-sintered blank was then removed and subjected to microwave-strengthened sintering to obtain a diamond metal composite material.

[0091] The frequency of the vibration magnetic field-assisted mixing is 60 Hz, and the power is 1200 W. The specific parameters of the discharge plasma sintering are: sintering temperature 655℃, heating rate 52℃ / min; applied pressure 32 MPa, pressure maintained at constant pressure; sintering time 8 min; plasma current 8000 A. The specific parameters of the microwave-enhanced sintering are: sintering temperature 855℃, heating rate 32℃ / min; applied pressure 42 MPa; sintering time 12 min.

[0092] Comparative Example 1

[0093] A diamond metal composite material and its preparation method are basically the same as those in Example 1, except that In and Ta are not added; and there is no intermediate Ti-Zr gradient deposition step.

[0094] Comparative Example 2

[0095] A diamond metal composite material and its preparation method are basically the same as those in Example 1, except that Zr and B are not added; and there is no outer alloying treatment step.

[0096] To further illustrate the beneficial technical effects of the diamond metal composite materials involved in the various embodiments of the present invention, relevant performance tests were conducted on the diamond metal composite materials involved in Examples 1-5 and Comparative Examples 1-2. The test results are shown in Table 1, and the test methods are as follows:

[0097] (1) Thermal conductivity: The laser flash method (NETZSCH LFA467) was used to test the sample size φ10×2mm according to GB / T 22588-2008.

[0098] (2) Wear ratio: The wear ratio was measured using a DHM-2 wear ratio tester. The SiC grinding wheel used in the test had an outer diameter of 100mm, an inner diameter of 20mm, and a thickness of 20mm. During the measurement, the pneumatic pressure was 500g, the grinding wheel linear speed was 15m / s, and the workpiece oscillation frequency was 35 times / min.

[0099] (3) Thermal expansion coefficient test: The thermal expansion coefficient of the composite material is measured using a static thermomechanical analyzer.

[0100] As can be seen from Table 1, the diamond metal composite material disclosed in the embodiments of the present invention has better thermal conductivity, wear resistance and high temperature resistance than the comparative product; the combination of In, Ta, Zr, B, intermediate Ti-Zr gradient deposition steps and outer alloying treatment steps is beneficial to improving the above properties.

[0101] Table 1

[0102] project thermal conductivity Wear ratio coefficient of thermal expansion unit W / (m·K) <![CDATA[×10 4 ]]> <![CDATA[×10 -6 / K]]> Example 1 892 13.7 5.8 Example 2 896 14.5 5.4 Example 3 904 15.5 4.8 Example 4 914 16.1 4.5 Example 5 919 16.9 4.0 Comparative Example 1 758 9.3 8.6 Comparative Example 2 745 8.7 8.0

[0103] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.

Claims

1. A diamond metal composite material, characterized in that, The material comprises a metal matrix and a diamond composite, wherein the volume percentage of the diamond composite is 60%-75% based on the total volume of the composite material; the diamond composite includes diamond particles and a gradient functional transition layer composited on the surface of the diamond particles; the metal matrix is ​​composed of the following components by mass percentage: Ag 1-3wt%, In 0.5-1.5wt%, rare earth elements 0.1-0.2wt%, B 0.001-0.01wt%, Ta 0.01-0.03wt%, Zr 0.05-0.1wt%, with the balance being Cu; the gradient functional transition layer consists of an inner layer, an intermediate layer, and an outer layer from the surface of the diamond particles outwards; the inner layer is a TiC layer with a thickness of 50-100nm; the intermediate layer is a Ti-Zr solid solution layer with a thickness of 200-500nm; and the outer layer is a Cu-Ti-Zr alloy layer with a thickness of 1-3μm.

2. The diamond metal composite material according to claim 1, characterized in that, The rare earth elements are La, Ce, and Y mixed in a mass ratio of 1:(0.8-1.2):(0.3-0.5).

3. The diamond metal composite material according to claim 1, characterized in that, The method for preparing the diamond composite includes the following steps: Step D1, Plasma etching of diamond surface: Place diamond particles in a plasma etching machine, introduce Ar / O2 mixed gas, and etch at 13.56MHz RF power of 500-800W to form a nanoscale pit structure on the surface. Step D2, Inner TiC Deposition: Deposition is carried out by magnetron sputtering with a Ti target as the source in an Ar / CH4 mixed gas atmosphere; Step D3, intermediate Ti-Zr gradient deposition: The sample with the inner layer deposited is transferred to the dual-target sputtering station for dual-target co-sputtering deposition; Step D4, outer alloying treatment: Immerse the deposited diamond particles into Cu-Ti-Zr molten alloy and impregnate for 10-20 minutes under ultrasonic vibration assistance to form an outer alloy layer.

4. The diamond metal composite material according to claim 3, characterized in that, The average particle size of the diamond particles in step D1 is 20-50 μm; the volume ratio of Ar to O2 in the Ar / O2 mixed gas in step D1 is 3:1; and the etching time in step D1 is 30-60 s.

5. The diamond metal composite material according to claim 3, characterized in that, In step D2, the flow ratio of Ar to CH4 in the Ar / CH4 mixed gas is 10:1; the deposition temperature in step D2 is 500-600℃, the bias voltage is -100 to -150V, and the deposition rate is 5-10nm / min.

6. The diamond metal composite material according to claim 3, characterized in that, The deposition temperature in step D3 is 600℃, the bias voltage is -80 to -120V, and it is divided into three stages. The initial stage lasts for 1-10 minutes, during which the Ti target power is 150W and the Zr target power is 150W. The intermediate stage lasts for 10-40 minutes, during which the Ti target power is increased from 150W to 225W and the Zr target power is decreased from 150W to 75W through linear adjustment controlled by the program. The final stage lasts for 40-60 minutes, during which the Ti target power is maintained at 225W and the Zr target power at 75W.

7. The diamond metal composite material according to claim 3, characterized in that, The Cu-Ti-Zr molten alloy described in step D4 comprises the following components by weight percentage: Ti 5wt%, Zr 3wt%, and the balance being Cu.

8. A method for preparing a diamond metal composite material according to any one of claims 1-7, characterized in that, The process includes the following steps: After uniformly mixing the metal matrix powder and diamond composite, the mixture is placed in a magnetic field oscillator under a vacuum of 10... -2 Mix the material with a vibratory magnetic field for 15-25 minutes. Then, slowly pour the mixed material into a graphite mold using a vibration filling method. After filling, place a graphite pressure head above the material, controlling the gap between the pressure head and the inner wall of the mold to be 0.1-0.2 mm. Then, place the graphite mold containing the material into a spark plasma sintering (SPCS) machine for SPCS. After SPCS, wait for the mold to cool to room temperature, remove the pre-sintered blank, and then perform microwave-strengthened sintering to obtain a diamond metal composite material.

9. The method for preparing diamond metal composite material according to claim 8, characterized in that, The frequency of the vibration magnetic field-assisted mixing is 60Hz, and the power is 1200W.

10. The method for preparing the diamond metal composite material according to claim 8, characterized in that, The specific parameters for the discharge plasma sintering are: sintering temperature 645-655℃, heating rate 48-52℃ / min; applied pressure 28-32MPa, pressure maintained at constant pressure; sintering time 5-8min; plasma current 8000A. The specific parameters for the microwave-enhanced sintering are: sintering temperature 845-855℃, heating rate 28-32℃ / min; applied pressure 38-42MPa; sintering time 8-12min.