Copper-containing diamond composite material as well as preparation method and application thereof

Abstract

The invention belongs to the field of metal-based composite materials, and provides a copper-containing diamond composite material and a preparation method and application thereof. The design that an in-situ zigzag TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surfaces of diamond particles is adopted, the thickness of the TiC interface layer ranges from 85 nm to 120 nm, the thickness of the titanium-copper gradient transition layer ranges from 172 nm to 1600 nm, the titanium-copper gradient transition layer is divided into a titanium-rich area, a gradient area and a copper-rich area, and the volume fraction of diamond ranges from 20% to 50%. The preparation method comprises the steps of hydrogen plasma etching pretreatment, gradient layer preparation through magnetron co-sputtering, staged temperature control sintering and post-treatment. According to the copper-diamond composite material, excellent heat conduction and mechanical properties are achieved, the zigzag interface layer and the gradient transition layer form an interlocking structure, interface bonding is effectively enhanced, the problems that a traditional copper-diamond composite material is weak in interface bonding and insufficient in performance are solved, and the copper-diamond composite material has wide application value.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composites, specifically to a copper-diamond composite material, its preparation method, and its applications. Background Technology

[0002] In high-end technology fields such as modern electronic devices, high-power LED lighting, power electronic equipment, and aerospace, thermal management has become a key bottleneck restricting product performance improvement and technological development. These application scenarios place extremely stringent performance requirements on heat dissipation materials. With the continuous increase in power density and integration of electronic devices, traditional heat dissipation materials are no longer sufficient to meet the urgent need for efficient heat conduction, necessitating the development of new composite materials with ultra-high thermal conductivity, excellent mechanical strength, and good processing performance. Copper-diamond composite materials, with their ultra-high thermal conductivity of diamond and the good processing performance of copper alloy matrix, have become an ideal candidate material for solving the heat dissipation problem of high-power devices. While meeting the requirements for high thermal conductivity, they also need sufficient mechanical strength to withstand mechanical and thermal stresses under complex operating conditions. The successful development of such composite materials is of great significance for promoting the development of the electronic information industry towards higher power density and miniaturization. Simultaneously, it provides key material support for breakthroughs in thermal management technologies in fields such as aerospace and new energy vehicles, significantly improving the reliability and service life of related products and driving technological progress and industrial upgrading across the entire industry.

[0003] Despite the theoretically excellent performance potential of copper-diamond composites, current research and industrial applications still face numerous technical challenges and performance limitations. For example, Chinese patent CN105838916A discloses a method for preparing diamond-copper composites, but it suffers from insufficient interfacial bonding strength, resulting in the composite material's overall thermal conductivity and mechanical properties failing to meet expectations. In traditional preparation methods, the interfacial bonding between diamond and the copper alloy matrix relies primarily on physical contact, lacking effective chemical bonding. This weak interfacial bonding not only severely restricts heat transfer efficiency but also leads to easy interface debonding and performance degradation during use. Furthermore, the chemical inertness of the diamond surface creates significant differences in wettability and a mismatch in thermal expansion coefficients between it and the copper alloy matrix, further exacerbating the difficulty of interfacial bonding. In addition, existing preparation processes lack effective interface design and control methods, failing to achieve effective stress transfer and minimize thermal resistance between diamond and the copper alloy matrix. These technical bottlenecks severely limit the full realization of the thermal conductivity and mechanical properties of copper-diamond composites, hindering their promotion and industrialization in high-end applications. Summary of the Invention

[0004] (1) Technical problems to be solved

[0005] The purpose of this invention is to provide a copper-diamond composite material, its preparation method and its application, to solve the problems of insufficient thermal conductivity and mechanical properties of current copper-diamond composite materials.

[0006] (2) Technical solution

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A copper-containing diamond composite material includes diamond particles, an in-situ TiC interface layer, a titanium-copper gradient transition layer, and a copper alloy matrix, wherein the diamond particles are dispersed in the copper alloy matrix as a reinforcing phase.

[0009] A TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surface of the diamond particles. The TiC interface layer is directly bonded to the diamond particles, and the titanium-copper gradient transition layer connects the TiC interface layer and the copper alloy matrix.

[0010] The in-situ TiC interface layer has a sawtooth micromorphology, and the average thickness of the TiC interface layer is 85-120 nm.

[0011] The total thickness of the titanium-copper gradient transition layer is 172-1600 nm;

[0012] The titanium-copper gradient transition layer is divided into three functional regions according to the atomic percentage of Ti and Cu: a titanium-rich region adjacent to the TiC interface layer, a gradient region in the middle, and a copper-rich region connecting the copper alloy matrix.

[0013] The volume fraction of diamond particles in the composite material is 20-50%, and the particle size of the diamond particles is 15-45 μm.

[0014] The copper alloy matrix is ​​selected from one of the Cu-Cr, Cu-Zr, Cu-Be, and Cu-Ag copper alloys.

[0015] Furthermore, the titanium-rich region has a thickness of 52-500 nm, a Ti content of 80-95 at%, and a Cu content of 5-20 at%. This titanium-rich region thickness is the remaining thickness of the pre-fabricated titanium-rich region layer after the Ti-C in-situ reaction during the preparation process. The gradient region has a thickness of 60-700 nm, with the Ti content gradually decreasing from 80 at% to 20 at%, and the Cu content correspondingly increasing from 20 at% to 80 at%. The copper-rich region has a thickness of 60-500 nm, a Cu content of 80-95 at%, and a Ti content of 5-20 at.

[0016] Furthermore, the serrated TiC interface layer is formed by the in-situ reaction between the activated diamond particle surface and Ti atoms in the titanium-rich region, forming an interlocking structure with the titanium-copper gradient transition layer.

[0017] This invention employs a dual-layer interface design, consisting of an in-situ TiC interface layer and a titanium-copper gradient transition layer, primarily to enhance the thermal conductivity and mechanical properties of copper-diamond composites. The core of this technical solution lies in achieving efficient bonding and synergistic effects between the diamond reinforcing phase and the copper alloy matrix through a meticulously designed multi-layer interface structure, thereby significantly improving the overall performance of the composite material. The in-situ TiC interface layer design aims to address the fundamental problems of poor wettability and weak chemical bonding between diamond and the copper alloy matrix. The titanium carbide layer formed through the in-situ Ti-C reaction constructs strong chemical bonds on the diamond surface. This chemical bonding method achieves a more stable and efficient interface connection compared to traditional physical contact. The serrated microstructure of the TiC interface layer further enhances the mechanical interlocking effect of the interface. This unique morphology not only increases the interface contact area but also significantly improves the interface shear strength and stress transfer efficiency through a geometric anchoring effect. The titanium-copper gradient transition layer design aims to alleviate the differences in thermal expansion coefficients and elastic modulus mismatch between diamond and the copper alloy matrix. Through three functional zones—a titanium-rich zone, a gradient zone, and a copper-rich zone—a smooth transition in composition and properties from the TiC interface layer to the copper alloy matrix is ​​achieved. The titanium-rich zone exhibits good chemical compatibility with the TiC interface layer, the gradient zone provides stress buffering and thermal conductivity bridging through the continuous variation of Ti and Cu composition, and the copper-rich zone ensures good bonding with the copper alloy matrix. This gradient design effectively disperses interfacial stress concentration, reduces the risk of interfacial cracking during thermal cycling, and provides a continuous heat transfer channel. The synergistic effect of the entire double-layer interface system fully utilizes the ultra-high thermal conductivity of diamond and the good machinability of the copper alloy matrix, resulting in a composite effect superior to simple combinations of single components, achieving simultaneous improvement in thermal conductivity and mechanical properties.

[0018] This invention also discloses a method for preparing a copper-containing diamond composite material, comprising the following steps:

[0019] S1. Directional pretreatment of diamond particle surface: Hydrogen plasma etching, directional activation and surface conditioning are used to obtain an active and smooth interface, which provides an ideal substrate for the uniform deposition of the subsequent titanium-copper gradient layer.

[0020] S2. Pre-preparation of titanium-copper gradient transition layer: Based on the activated surface obtained in step S1, titanium-rich region, gradient region and copper-rich region are sequentially deposited on the surface of diamond particles using magnetron co-sputtering technology and segmented power-adjustable deposition method to form a pre-coated structure with gradient composition distribution.

[0021] S3. Controlled high-temperature sintering composite: Through precise staged temperature control, the in-situ reaction of Ti-C is activated. At a sintering temperature of 870-920℃, Ti atoms in the titanium-rich region react with the activated diamond surface to generate a serrated TiC interface layer.

[0022] S4. Post-processing, including controlled cooling and stabilization, to ensure the stability of the newly formed interface structure and eliminate reactive stress.

[0023] Furthermore, in step S1, the hydrogen plasma etching process involves treating the diamond particles in hydrogen plasma for 5-15 minutes at a temperature of 400-500°C and a plasma power of 200-600W to remove the oxide layer and impurities on the surface, exposing a clean and flat surface. Subsequently, a directional activation process is performed in an inert atmosphere at a temperature of 600-750°C for 30-180 minutes to form a high density of reactive sites on the flat surface. Finally, the pretreatment parameters are precisely controlled through surface conditioning to form a uniform active distribution on the surface of the diamond particles that is conducive to the subsequent Ti-C reaction.

[0024] Furthermore, in step S2, the substrate temperature of the magnetron co-sputtering technology is 200-400℃ to ensure uniform deposition of a titanium-copper gradient transition layer on the flat surface of the activated diamond particles, and the sputtering deposition rate is 2-8 nm / min.

[0025] The segmented power-adjusted deposition method in step S2 includes first depositing a titanium-rich prefabricated layer with a titanium target power of 250-300W and a copper target power of 10-30W, controlling the prefabricated layer thickness within the range of 80-600nm. Then, gradient deposition is performed in 5-8 deposition segments, with the titanium target power decreasing from 250-300W to 50-80W and the copper target power increasing from 10-30W to 250-280W, controlling the deposition thickness within the range of 60-700nm. Finally, when depositing the copper-rich region, the copper target power is 250-300W and the titanium target power is 10-30W, controlling the deposition thickness within the range of 60-500nm. After the Ti-C in-situ reaction in step S3, some Ti atoms in the titanium-rich prefabricated layer are converted into a TiC interface layer.

[0026] Furthermore, the staged temperature control in step S3 includes the following: In the first stage, the temperature is slowly increased to 750-800℃ at a rate of 1-3℃ / min and held for 30-60 minutes for pre-reaction nucleation. During this stage, the activated diamond particles begin to react initially with Ti atoms at the interface of the adjacent titanium-rich region. In the second stage, the temperature is increased to 870-920℃ at a rate of 2-5℃ / min and held for 2-4 hours. During this stage, the Ti-C reaction proceeds fully, and TiC exhibits a serrated microstructure from the flat interface to the titanium-copper gradient. The transition layer grows at a rate of 20-40 nm / h to achieve an average thickness of 85-120 nm. In the third stage, the temperature is lowered to below 500 °C at a rate of 3-8 °C / min and then allowed to cool naturally to room temperature. During the second stage sintering process, a slower heating rate of 2-3 °C / min and a longer holding time of 3-4 hours are conducive to the full diffusion of Ti atoms to form a large serrated structure, while a faster heating rate of 4-5 °C / min and a shorter holding time of 2-2.5 hours restrict the diffusion to form a small serrated structure.

[0027] Furthermore, the controlled high-temperature sintering composite in step S3 adopts hot isostatic pressing or powder metallurgy sintering process, with a sintering pressure of 60-180MPa. Appropriate pressure is conducive to the full contact between the surface of the activated diamond particles and the titanium-rich area and the Ti-C reaction, promoting the formation of the serrated micro-morphology TiC interface layer. The holding time is 2-5 hours, and the sintering atmosphere is a vacuum or inert gas protection.

[0028] Furthermore, the post-processing in step S4 includes firstly, briefly holding the TiC interface layer at 600-650℃ for 10-30 minutes during controlled cooling to stabilize the newly formed TiC interface layer structure with an average thickness of 85-120nm and a sawtooth microstructure; then, performing a low-temperature annealing treatment at 500-650℃ for 10-60 minutes under an inert atmosphere to eliminate the internal stress generated during the Ti-C reaction and optimize the bonding between the sawtooth TiC interface layer and the titanium-copper gradient transition layer; finally, performing a stress release treatment by holding the TiC interface layer at 200-400℃ for 1-4 hours to ensure the stable bonding between the diamond particles dispersed in the copper alloy matrix and the TiC interface layer and the titanium-copper gradient transition layer formed sequentially on its surface.

[0029] (3) Beneficial technical effects

[0030] 1) Significantly enhanced interfacial bonding strength: Through the dual effects of chemical bonding of the in-situ TiC interfacial layer and mechanical interlocking of the serrated microstructure, the problem of weak interfacial bonding in traditional copper-diamond composite materials is effectively solved, and strong chemical bonding between diamond and copper alloy matrix is ​​achieved.

[0031] 2) Significantly improved stress transfer efficiency: The three-zone functional design of the titanium-copper gradient transition layer effectively alleviates the difference in thermal expansion coefficients and elastic modulus mismatch between diamond and copper alloy matrix through the smooth transition of composition and properties, and significantly improves stress transfer efficiency.

[0032] 3) Excellent thermal conductivity: The double-layer interface structure provides a continuous and efficient heat transfer channel, giving full play to the ultra-high thermal conductivity of diamond and achieving a significant improvement in the overall thermal conductivity of the composite material.

[0033] 4) Precise and controllable preparation process: The preparation method of segmented surface treatment combined with in-situ reaction realizes precise control of interface structure. The organic combination of hydrogen plasma etching, directional activation, magnetron co-sputtering and staged sintering process ensures the stability and reproducibility of product quality.

[0034] 5) Good structural stability: The post-treatment process of controlled cooling and graded heat treatment effectively eliminates the internal stress generated during the Ti-C reaction, ensuring the structural stability and long-term reliability of the composite material under complex working conditions.

[0035] 6) Significant synergistic enhancement effect: The synergistic effect of the multi-layer interface system allows the excellent performance of each component to be fully utilized and effectively combined, achieving an enhancement effect that far exceeds that of a simple combination of single materials. Attached Figure Description

[0036] Figure 1 The microstructure characteristics and line scan elemental distribution of the copper-containing diamond composite material prepared in Example 2 of this invention are shown.

[0037] Figure 2 This is a comparison chart of the thermal conductivity and coefficient of thermal expansion performance of the embodiments and comparative examples of the present invention.

[0038] Figure 3 This is a comparison chart of the bending strength and elastic modulus properties of the embodiments and comparative examples of the present invention.

[0039] Figure 4 This is a comparison chart of Vickers hardness and thermal cycling stability in the embodiments and comparative examples of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0041] Example 1

[0042] A copper-containing diamond composite material includes diamond particles, an in-situ TiC interface layer, a titanium-copper gradient transition layer, and a copper alloy matrix, wherein the diamond particles are dispersed in the copper alloy matrix as a reinforcing phase.

[0043] A TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surface of the diamond particles. The TiC interface layer is directly bonded to the diamond particles, and the titanium-copper gradient transition layer connects the TiC interface layer and the copper alloy matrix. The in-situ TiC interface layer has a serrated microstructure and an average thickness of 95 nm. The total thickness of the titanium-copper gradient transition layer is 350 nm. The titanium-copper gradient transition layer is divided into three functional regions according to the atomic percentage of Ti and Cu: a titanium-rich region adjacent to the TiC interface layer, a gradient region in the middle, and a copper-rich region connecting the copper alloy matrix. The volume fraction of diamond particles in the composite material is 30%, and the particle size of the diamond particles is 25 μm. The copper alloy matrix in this embodiment is selected from the Cu-Cr system. The titanium-rich region has a thickness of 150 nm, a Ti content of 85 at%, and a Cu content of 15 at%. This thickness represents the remaining thickness of the pre-fabricated titanium-rich region layer after the in-situ reaction of Ti-C during the preparation process. The gradient region has a thickness of 100 nm, with the Ti content gradually decreasing from 80 at% to 20 at%, and the Cu content correspondingly increasing from 20 at% to 80 at%. The copper-rich region has a thickness of 100 nm, a Cu content of 85 at%, and a Ti content of 15 at%. The serrated TiC interface layer is formed through the in-situ reaction of activated diamond particles with Ti atoms in the titanium-rich region, forming an interlocking structure with the titanium-copper gradient transition layer.

[0044] The preparation method of a copper-containing diamond composite material according to this embodiment includes the following steps:

[0045] S1. Oriented pretreatment of diamond particle surface: A smooth and active interface is obtained through hydrogen plasma etching, directional activation, and surface conditioning, providing an ideal substrate for the uniform deposition of the subsequent titanium-copper gradient layer. Hydrogen plasma etching is performed in hydrogen plasma for 10 minutes at a temperature of 450°C and a plasma power of 400W to remove the oxide layer and impurities on the diamond particle surface, exposing a clean and smooth surface. Subsequently, directional activation is performed in an inert atmosphere at a temperature of 675°C for 90 minutes to form a high density of reactive sites on the smooth surface. Finally, surface conditioning precisely controls the pretreatment parameters to form a uniform active distribution on the diamond particle surface that is conducive to the subsequent Ti-C reaction.

[0046] S2. Pre-preparation of the titanium-copper gradient transition layer: Based on the activated surface obtained in step S1, a titanium-rich region, a gradient region, and a copper-rich region are sequentially deposited on the surface of diamond particles using magnetron co-sputtering technology and a segmented power-controlled deposition method to form a pre-coated structure with a gradient composition distribution. The segmented power-controlled deposition method includes first depositing the titanium-rich region pre-layer with a titanium target power of 275W and a copper target power of 20W, and controlling the pre-layer thickness to 250nm. Then, the gradient region deposition is divided into 6 deposition segments, with the titanium target power decreasing from 275W to 65W segment by segment and the copper target power increasing from 20W to 265W segment by segment, and the deposition thickness controlled to 100nm. Finally, when completing the copper-rich region deposition, the copper target power is 275W and the titanium target power is 20W, and the deposition thickness is controlled to 100nm. After the Ti-C in-situ reaction in step S3, some Ti atoms in the titanium-rich region pre-layer are converted into the TiC interface layer. The substrate temperature of the magnetron co-sputtering technology is 300℃, which ensures uniform deposition of a titanium-copper gradient transition layer on the flat surface of the activated diamond particles, and the sputtering deposition rate is 5nm / min.

[0047] S3. Controlled high-temperature sintering composite: Through precise staged temperature control, the in-situ reaction of Ti-C is activated. At a sintering temperature of 895℃, Ti atoms in the titanium-rich region react with the activated diamond surface to form a serrated TiC interface layer. The staged temperature control includes the following stages: First stage: the temperature is slowly increased to 775℃ at 2℃ / min and held for 45 minutes for pre-reaction nucleation. In this stage, the activated diamond particle surface begins to react with Ti atoms at the interface of the adjacent titanium-rich region. Second stage: the temperature is increased to 895℃ at 3℃ / min and held for 3 hours. In this stage, the Ti-C reaction is fully carried out, and TiC grows with a serrated micromorphology from the flat interface towards the titanium-copper gradient transition layer at a growth rate of 30nm / h. Third stage: the temperature is decreased to below 500℃ at 5℃ / min and then naturally cooled to room temperature. The controlled high-temperature sintering composite adopts the hot isostatic pressing sintering process with a sintering pressure of 120 MPa. The appropriate pressure is conducive to the full contact between the surface of the activated diamond particles and the titanium-rich zone and the Ti-C reaction, promoting the formation of the serrated micro-morphology TiC interface layer. The holding time is 3 hours, and the sintering atmosphere is vacuum protected.

[0048] S4. Post-processing, including controlled cooling and stabilization, ensures the stability of the newly formed interface structure and eliminates reaction stress. The post-processing includes first briefly holding at 625°C for 20 minutes during controlled cooling to stabilize the newly formed serrated TiC interface layer structure; then, performing a low-temperature annealing treatment at 575°C for 30 minutes under an inert atmosphere to eliminate internal stress generated during the Ti-C reaction and optimize the bonding between the serrated TiC interface layer and the titanium-copper gradient transition layer; finally, performing a stress release treatment at 300°C for 2 hours to ensure stable bonding between the diamond particles dispersed in the copper alloy matrix and the TiC interface layer and titanium-copper gradient transition layer sequentially formed on its surface.

[0049] Example 1 employs a relatively conservative, moderate parameter configuration, reflecting a design philosophy prioritizing stability. This example selects a moderate diamond particle volume fraction of 30% and a particle size of 25 μm to ensure a good balance between the reinforcing phase and the matrix. The TiC interface layer thickness of 95 nm and the total thickness of the titanium-copper gradient transition layer of 350 nm are at a moderate level within the parameter range, ensuring interfacial bonding strength while avoiding stress concentration issues that may arise from excessively thick coatings. Fabrication process parameters such as a hydrogen plasma treatment power of 400 W, a sintering temperature of 895 °C, and a sintering pressure of 120 MPa are all selected at moderate values ​​to ensure process controllability and reproducibility. This example is suitable for standard heat dissipation applications with high reliability requirements, such as electronic heat dissipation devices, LED heat dissipation substrates, and automotive electronic power modules. These applications demand high material performance stability and mature fabrication processes.

[0050] Example 2

[0051] A copper-containing diamond composite material includes diamond particles, an in-situ TiC interface layer, a titanium-copper gradient transition layer, and a copper alloy matrix, wherein the diamond particles are dispersed in the copper alloy matrix as a reinforcing phase.

[0052] A TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surface of the diamond particles. The TiC interface layer is directly bonded to the diamond particles, and the titanium-copper gradient transition layer connects the TiC interface layer and the copper alloy matrix. The in-situ TiC interface layer has a serrated microstructure and an average thickness of 85 nm. The total thickness of the titanium-copper gradient transition layer is 172 nm. The titanium-copper gradient transition layer is divided into three functional regions according to the atomic percentage of Ti and Cu: a titanium-rich region adjacent to the TiC interface layer, a gradient region in the middle, and a copper-rich region connecting the copper alloy matrix. The volume fraction of diamond particles in the composite material is 50%, and the particle size of the diamond particles is 15 μm. The copper alloy matrix in this embodiment is selected from the Cu-Zr system. The titanium-rich region has a thickness of 52 nm, a Ti content of 95 at%, and a Cu content of 5 at%. This thickness represents the remaining thickness of the pre-fabricated titanium-rich region layer after the in-situ reaction of Ti-C during the preparation process. The gradient region has a thickness of 60 nm, with the Ti content gradually decreasing from 80 at% to 20 at%, and the Cu content correspondingly increasing from 20 at% to 80 at%. The copper-rich region has a thickness of 60 nm, a Cu content of 95 at%, and a Ti content of 5 at%. The serrated TiC interface layer is formed through the in-situ reaction of activated diamond particles with Ti atoms in the titanium-rich region, forming an interlocking structure with the titanium-copper gradient transition layer.

[0053] The preparation method of a copper-containing diamond composite material according to this embodiment includes the following steps:

[0054] S1. Oriented pretreatment of diamond particle surface: A smooth and active interface is obtained through hydrogen plasma etching, directional activation, and surface conditioning, providing an ideal substrate for the uniform deposition of the subsequent titanium-copper gradient layer. Hydrogen plasma etching is performed in hydrogen plasma for 15 minutes at a temperature of 500℃ and a plasma power of 600W to remove the oxide layer and impurities on the diamond particle surface, exposing a clean and smooth surface. Subsequently, directional activation is performed in an inert atmosphere at a temperature of 750℃ for 180 minutes to form a high density of reactive sites on the smooth surface. Finally, surface conditioning precisely controls the pretreatment parameters to form a uniform active distribution on the diamond particle surface that is conducive to the subsequent Ti-C reaction.

[0055] S2. Pre-preparation of the titanium-copper gradient transition layer: Based on the activated surface obtained in step S1, a titanium-rich region, a gradient region, and a copper-rich region are sequentially deposited on the surface of diamond particles using magnetron co-sputtering technology and a segmented power-controlled deposition method to form a pre-coated structure with a gradient composition distribution. The segmented power-controlled deposition method includes first depositing the titanium-rich region pre-layer with a titanium target power of 300W and a copper target power of 10W, and controlling the pre-layer thickness to 80nm. Then, the gradient region deposition is divided into 5 deposition segments, with the titanium target power decreasing from 300W to 50W in each segment and the copper target power increasing from 10W to 250W in each segment, and the deposition thickness controlled to 60nm. Finally, when the copper-rich region is deposited, the copper target power is 300W and the titanium target power is 10W, and the deposition thickness is controlled to 60nm. After the Ti-C in-situ reaction in step S3, some Ti atoms in the titanium-rich region pre-layer are converted into the TiC interface layer. The substrate temperature of the magnetron co-sputtering technology is 200℃, which ensures uniform deposition of a titanium-copper gradient transition layer on the flat surface of the activated diamond particles, and the sputtering deposition rate is 2nm / min.

[0056] S3. Controlled high-temperature sintering composite: Through precise staged temperature control, the in-situ reaction of Ti-C is activated. At a sintering temperature of 920℃, Ti atoms in the titanium-rich region react with the activated diamond surface to form a serrated TiC interface layer. The staged temperature control includes the following stages: First stage: the temperature is slowly increased to 750℃ at 1℃ / min and held for 60 minutes for pre-reaction nucleation. In this stage, the activated diamond particle surface begins to react with Ti atoms at the interface of the adjacent titanium-rich region. Second stage: the temperature is increased to 920℃ at 5℃ / min and held for 2 hours. In this stage, the Ti-C reaction proceeds fully, and TiC grows with a serrated micromorphology from the flat interface towards the titanium-copper gradient transition layer at a growth rate of 40nm / h. Third stage: the temperature is decreased to below 500℃ at 8℃ / min and then naturally cooled to room temperature. The controlled high-temperature sintering composite adopts powder metallurgy sintering process with a sintering pressure of 180 MPa. The appropriate pressure is conducive to the full contact between the surface of the activated diamond particles and the titanium-rich zone and the Ti-C reaction, promoting the formation of the serrated micro-morphology TiC interface layer. The holding time is 2 hours, and the sintering atmosphere is an inert gas protection.

[0057] S4. Post-processing, including controlled cooling and stabilization, ensures the stability of the newly formed interface structure and eliminates reaction stress. The post-processing includes first briefly holding at 650°C for 10 minutes during controlled cooling to stabilize the newly formed serrated TiC interface layer structure; then, performing low-temperature annealing at 650°C for 10 minutes under an inert atmosphere to eliminate internal stress generated during the Ti-C reaction and optimize the bonding between the serrated TiC interface layer and the titanium-copper gradient transition layer; finally, performing stress release treatment by holding at 400°C for 1 hour to ensure stable bonding between the diamond particles dispersed in the copper alloy matrix and the TiC interface layer and titanium-copper gradient transition layer sequentially formed on its surface.

[0058] Example 2 employs a high volume fraction, small particle size design strategy, highlighting the high-density reinforcement characteristic. This example selects the highest diamond particle volume fraction of 50% and the smallest particle size of 15 μm to achieve a high-density distribution of the reinforcing phase. Simultaneously, a relatively thin interface layer design is used, with a TiC interface layer thickness of 85 nm and a total titanium-copper gradient transition layer thickness of 172 nm, reflecting the concept of refined interface control. The fabrication process utilizes a high plasma power of 600 W, a maximum sintering temperature of 920 °C, and a maximum sintering pressure of 180 MPa, ensuring sufficient activation of the small-diameter diamond and complete interfacial reactions. This example is particularly suitable for high-end applications with extremely high thermal conductivity requirements, such as heat dissipation in high-power-density electronic devices, high-power LED chips, and power amplifiers for 5G communication base stations.

[0059] Example 3

[0060] A copper-containing diamond composite material includes diamond particles, an in-situ TiC interface layer, a titanium-copper gradient transition layer, and a copper alloy matrix, wherein the diamond particles are dispersed in the copper alloy matrix as a reinforcing phase.

[0061] A TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surface of the diamond particles. The TiC interface layer is directly bonded to the diamond particles, and the titanium-copper gradient transition layer connects the TiC interface layer and the copper alloy matrix. The in-situ TiC interface layer has a serrated microstructure and an average thickness of 120 nm. The total thickness of the titanium-copper gradient transition layer is 1100 nm. The titanium-copper gradient transition layer is divided into three functional regions according to the atomic percentage of Ti and Cu: a titanium-rich region adjacent to the TiC interface layer, a gradient region in the middle, and a copper-rich region connecting the copper alloy matrix. The volume fraction of diamond particles in the composite material is 20%, and the particle size of the diamond particles is 45 μm. The copper alloy matrix in this embodiment is selected from the Cu-Be system. The titanium-rich region has a thickness of 350 nm, with a Ti content of 80 at% and a Cu content of 20 at%. This thickness represents the remaining thickness of the pre-fabricated titanium-rich region layer after the in-situ reaction of Ti-C during the preparation process. The gradient region has a thickness of 450 nm, with the Ti content gradually decreasing from 80 at% to 20 at%, and the Cu content correspondingly increasing from 20 at% to 80 at%. The copper-rich region has a thickness of 300 nm, with a Cu content of 80 at% and a Ti content of 20 at%. The serrated TiC interface layer is formed through the in-situ reaction of activated diamond particles with Ti atoms in the titanium-rich region, forming an interlocking structure with the titanium-copper gradient transition layer.

[0062] The preparation method of a copper-containing diamond composite material according to this embodiment includes the following steps:

[0063] S1. Oriented pretreatment of diamond particle surface: An active and smooth interface is obtained through hydrogen plasma etching, directional activation treatment, and surface conditioning, providing an ideal substrate for the uniform deposition of the subsequent titanium-copper gradient layer. Hydrogen plasma etching is performed in hydrogen plasma for 5 minutes at a temperature of 400℃ and a plasma power of 200W to remove the oxide layer and impurities on the diamond particle surface, exposing a clean and smooth surface. Subsequently, directional activation treatment is performed in an inert atmosphere at a temperature of 600℃ for 30 minutes to form a high density of reactive sites on the smooth surface. Finally, surface conditioning is used to precisely control the pretreatment parameters to form a uniform active distribution on the diamond particle surface that is conducive to the subsequent Ti-C reaction.

[0064] S2. Pre-preparation of the titanium-copper gradient transition layer: Based on the activated surface obtained in step S1, a titanium-rich region, a gradient region, and a copper-rich region are sequentially deposited on the surface of diamond particles using magnetron co-sputtering technology and a segmented power-controlled deposition method to form a pre-coated structure with a gradient composition distribution. The segmented power-controlled deposition method includes first depositing the titanium-rich region pre-layer with a titanium target power of 250W and a copper target power of 30W, and controlling the pre-layer thickness to 470nm. Then, the gradient region deposition is divided into 8 deposition segments, with the titanium target power decreasing from 250W to 80W segment by segment and the copper target power increasing from 30W to 280W segment by segment, and the deposition thickness controlled to 450nm. Finally, when the copper-rich region is deposited, the copper target power is 250W and the titanium target power is 30W, and the deposition thickness is controlled to 300nm. After the Ti-C in-situ reaction in step S3, some Ti atoms in the titanium-rich region pre-layer are converted into the TiC interface layer. The substrate temperature of the magnetron co-sputtering technology is 400℃, which ensures uniform deposition of a titanium-copper gradient transition layer on the flat surface of the activated diamond particles, and the sputtering deposition rate is 8nm / min.

[0065] S3. Controlled high-temperature sintering composite: Through precise staged temperature control, the in-situ reaction of Ti-C is activated. At a sintering temperature of 870℃, Ti atoms in the titanium-rich region react with the activated diamond surface to form a serrated TiC interface layer. The staged temperature control includes the following stages: First stage: slowly increase the temperature to 800℃ at 3℃ / min and hold for 30 minutes for pre-reaction nucleation. In this stage, the activated diamond particle surface begins to react with Ti atoms at the interface of the adjacent titanium-rich region. Second stage: increase the temperature to 870℃ at 2℃ / min and hold for 4 hours. In this stage, the Ti-C reaction proceeds fully, and TiC grows with a serrated micromorphology from the flat interface towards the titanium-copper gradient transition layer at a growth rate of 20nm / h. Third stage: decrease the temperature to below 500℃ at 3℃ / min and then allow it to cool naturally to room temperature. The controlled high-temperature sintering composite adopts the hot isostatic pressing sintering process with a sintering pressure of 60 MPa. The appropriate pressure is conducive to the full contact between the surface of the activated diamond particles and the titanium-rich zone and the Ti-C reaction, promoting the formation of the serrated micro-morphology TiC interface layer. The holding time is 5 hours, and the sintering atmosphere is vacuum protected.

[0066] S4. Post-processing, including controlled cooling and stabilization, ensures the stability of the newly formed interface structure and eliminates reaction stress. The post-processing includes first briefly holding at 600℃ for 30 minutes during controlled cooling to stabilize the newly formed serrated TiC interface layer structure; then, performing a low-temperature annealing treatment at 500℃ for 60 minutes under an inert atmosphere to eliminate internal stress generated during the Ti-C reaction and optimize the bonding between the serrated TiC interface layer and the titanium-copper gradient transition layer; finally, performing a stress release treatment by holding at 200℃ for 4 hours to ensure stable bonding between the diamond particles dispersed in the copper alloy matrix and the TiC interface layer and titanium-copper gradient transition layer sequentially formed on its surface.

[0067] Example 3 employs a design scheme combining large-particle-size, low-volume-fraction diamond with a thick interface layer, emphasizing the importance of interface optimization and stress buffering. This example selects a maximum diamond particle size of 45 μm and a minimum volume fraction of 20% to reduce interparticle interactions; simultaneously, it utilizes a thickest TiC interface layer of 120 nm and a relatively thick titanium-copper gradient transition layer of 1100 nm, providing ample stress buffering space. The fabrication process employs relatively mild parameters, such as a minimum plasma power of 200 W, a minimum sintering temperature of 870 °C, and a minimum sintering pressure of 60 MPa, ensuring gentle processing of the large-particle-size diamond. This example is suitable for extreme environmental applications with stringent requirements for thermal cycling stability and long-term reliability, such as aerospace thermal management systems, nuclear power plant electronic equipment heat dissipation, and high-temperature industrial electronic equipment.

[0068] Example 4

[0069] A copper-containing diamond composite material includes diamond particles, an in-situ TiC interface layer, a titanium-copper gradient transition layer, and a copper alloy matrix, wherein the diamond particles are dispersed in the copper alloy matrix as a reinforcing phase.

[0070] A TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surface of the diamond particles. The TiC interface layer is directly bonded to the diamond particles, and the titanium-copper gradient transition layer connects the TiC interface layer and the copper alloy matrix. The in-situ TiC interface layer has a serrated microstructure and an average thickness of 110 nm. The total thickness of the titanium-copper gradient transition layer is 1600 nm. The titanium-copper gradient transition layer is divided into three functional regions according to the atomic percentage of Ti and Cu: a titanium-rich region adjacent to the TiC interface layer, a gradient region in the middle, and a copper-rich region connecting the copper alloy matrix. The volume fraction of diamond particles in the composite material is 40%, and the particle size of the diamond particles is 35 μm. The copper alloy matrix in this embodiment is selected from Cu-Ag copper alloys. The titanium-rich region has a thickness of 500 nm, a Ti content of 90 at%, and a Cu content of 10 at%. This thickness represents the remaining thickness of the pre-fabricated titanium-rich region layer after the in-situ reaction of Ti-C during the preparation process. The gradient region has a thickness of 700 nm, with the Ti content gradually decreasing from 80 at% to 20 at%, and the Cu content correspondingly increasing from 20 at% to 80 at%. The copper-rich region has a thickness of 400 nm, a Cu content of 90 at%, and a Ti content of 10 at%. The serrated TiC interface layer is formed through the in-situ reaction of activated diamond particles with Ti atoms in the titanium-rich region, forming an interlocking structure with the titanium-copper gradient transition layer.

[0071] The preparation method of a copper-containing diamond composite material according to this embodiment includes the following steps:

[0072] S1. Oriented pretreatment of diamond particle surface: A smooth and active interface is obtained through hydrogen plasma etching, directional activation, and surface conditioning, providing an ideal substrate for the uniform deposition of the subsequent titanium-copper gradient layer. Hydrogen plasma etching is performed in hydrogen plasma for 8 minutes at a temperature of 475°C and a plasma power of 350W to remove the oxide layer and impurities on the diamond particle surface, exposing a clean and smooth surface. Subsequently, directional activation is performed in an inert atmosphere at 700°C for 120 minutes to form a high density of reactive sites on the smooth surface. Finally, surface conditioning precisely controls the pretreatment parameters to form a uniform active distribution on the diamond particle surface that is conducive to the subsequent Ti-C reaction.

[0073] S2. Pre-preparation of the titanium-copper gradient transition layer: Based on the activated surface obtained in step S1, a titanium-rich region, a gradient region, and a copper-rich region are sequentially deposited on the surface of diamond particles using magnetron co-sputtering technology and a segmented power-controlled deposition method to form a pre-coated structure with a gradient composition distribution. The segmented power-controlled deposition method includes first depositing the titanium-rich region pre-layer with a titanium target power of 280W and a copper target power of 15W, controlling the pre-layer thickness to 600nm. Then, the gradient region deposition is divided into 7 deposition segments, with the titanium target power decreasing from 280W to 60W segment by segment and the copper target power increasing from 15W to 275W segment by segment, controlling the deposition thickness to 700nm. Finally, when the copper-rich region is deposited, the copper target power is 280W and the titanium target power is 15W, controlling the deposition thickness to 400nm. After the Ti-C in-situ reaction in step S3, some Ti atoms in the titanium-rich region pre-layer are converted into the TiC interface layer. The substrate temperature of the magnetron co-sputtering technology is 350℃, which ensures uniform deposition of a titanium-copper gradient transition layer on the flat surface of the activated diamond particles, and the sputtering deposition rate is 6nm / min.

[0074] S3. Controlled high-temperature sintering composite: Through precise staged temperature control, the in-situ reaction of Ti-C is activated. At a sintering temperature of 900℃, Ti atoms in the titanium-rich region react with the activated diamond surface to form a serrated TiC interface layer. The staged temperature control includes the following stages: First stage: the temperature is slowly increased to 780℃ at 2℃ / min and held for 50 minutes for pre-reaction nucleation. In this stage, the activated diamond particle surface begins to react with Ti atoms at the interface of the adjacent titanium-rich region. Second stage: the temperature is increased to 900℃ at 4℃ / min and held for 2.5 hours. In this stage, the Ti-C reaction proceeds fully, and TiC grows with a serrated micromorphology from the flat interface towards the titanium-copper gradient transition layer at a growth rate of 35nm / h. Third stage: the temperature is decreased to below 500℃ at 6℃ / min and then naturally cooled to room temperature. The controlled high-temperature sintering composite adopts powder metallurgy sintering process with a sintering pressure of 150 MPa. The appropriate pressure is conducive to the full contact between the surface of the activated diamond particles and the titanium-rich zone and the Ti-C reaction, promoting the formation of the serrated micro-morphology TiC interface layer. The holding time is 4 hours, and the sintering atmosphere is an inert gas protection.

[0075] S4. Post-processing, including controlled cooling and stabilization, ensures the stability of the newly formed interface structure and eliminates reaction stress. The post-processing includes first briefly holding at 635°C for 25 minutes during controlled cooling to stabilize the newly formed serrated TiC interface layer structure; then performing a low-temperature annealing treatment at 600°C for 45 minutes under an inert atmosphere to eliminate internal stress generated during the Ti-C reaction and optimize the bonding between the serrated TiC interface layer and the titanium-copper gradient transition layer; finally, a stress-relieving treatment is performed at 350°C for 3 hours to ensure stable bonding between the diamond particles dispersed in the copper alloy matrix and the TiC interface layer and titanium-copper gradient transition layer sequentially formed on its surface.

[0076] Example 4 embodies a design philosophy that balances high performance with process optimization, employing a parameter combination that is close to the limits yet still safe. This example selects a relatively high diamond particle volume fraction of 40% and a relatively large particle size of 35μm to maintain good processing performance while ensuring reinforcement. The interface layer thickness is designed as a 110nm TiC interface layer and a maximum 1600nm titanium-copper gradient transition layer, achieving optimal stress distribution and heat conduction channels. The fabrication process parameters, such as a moderately high plasma power of 350W, a relatively high sintering temperature of 900℃, and a moderately high pressure of 150MPa, demonstrate the best balance between performance and operability. This example is suitable for high-power industrial applications with high comprehensive performance requirements, such as power electronic modules for electric vehicles, heat dissipation in wind power converters, heat dissipation in rail transit traction systems, and heat dissipation in data center servers.

[0077] Comparative Example 1: Basically the same as Example 1, except that the hydrogen plasma etching power was 100W, the processing time was 5 minutes, and the processing temperature was 300℃, which failed to fully remove the oxide layer and impurities on the surface of the diamond particles.

[0078] Comparative Example 2: It is basically the same as Example 1, except that the directional activation treatment temperature is 500°C, the treatment time is 15 minutes, and it is carried out in an inert atmosphere, resulting in a lower density of reactive sites.

[0079] Comparative Example 3: It is basically the same as Example 1, except that the substrate temperature is 100°C and the sputtering deposition rate is 1 nm / min during the magnetron co-sputtering deposition process, which results in insufficient adhesion of the titanium-copper gradient transition layer on the surface of diamond particles.

[0080] Comparative Example 4: It is basically the same as Example 1, except that the titanium target power is 150W and the copper target power is 50W when the titanium-rich prefabricated layer is deposited, the titanium target power decreases from 150W to 100W in stages and the copper target power increases from 50W to 150W in stages when the gradient region is deposited, and the copper target power is 150W and the titanium target power is 50W when the copper-rich region is deposited, so the resulting compositional gradient is not obvious.

[0081] Comparative Example 5: It is basically the same as Example 1, except that in the staged temperature control, the first stage heating rate is 5℃ / min to rapidly heat to 750℃ and hold for 15 minutes, and the second stage heating rate is 8℃ / min to heat to 895℃ and hold for 1 hour, resulting in insufficient Ti-C reaction.

[0082] Comparative Example 6: It is basically the same as Example 1, except that the sintering pressure is 30 MPa, the sintering temperature is 800 °C, the holding time is 1 hour, the degree of in-situ reaction of Ti-C is insufficient, and the thickness of the TiC interface layer formed is only 40 nm.

[0083] Comparative Example 7: It is basically the same as Example 1, except that the cooling process in the post-processing is controlled to be held at 500°C for 5 minutes, the low-temperature annealing process is held at 400°C for 5 minutes, and the stress relief process is held at 100°C for 30 minutes, resulting in insufficient elimination of internal stress.

[0084] Comparative Example 8: It is basically the same as Example 1, except that only a single titanium-copper gradient transition layer is formed on the surface of the diamond particles, without the in-situ TiC interface layer, and the titanium-copper gradient transition layer is in direct contact with the diamond particles.

[0085] Comparative Example 9: It is basically the same as Example 1, except that the titanium-copper gradient transition layer only contains two functional regions: a titanium-rich region and a copper-rich region. The titanium-rich region has a Ti content of 85 at% and a Cu content of 15 at%, and the copper-rich region has a Cu content of 85 at% and a Ti content of 15 at%. No intermediate gradient region is set.

[0086] Comparative Example 10: It is basically the same as Example 1, except that it is prepared by a traditional powder mixing and sintering process. Diamond particles, titanium powder and copper powder are directly mixed and sintered at 870°C for 3 hours at a pressure of 100MPa. No surface pretreatment and layered deposition process are performed.

[0087] Performance testing:

[0088] Thermal conductivity testing experiment: The test object was a copper-containing diamond composite material sample. The purpose of the test was to evaluate the thermal conductivity and thermal diffusivity of the material. The test principle was based on measuring thermal diffusivity using the laser flash method, and calculating the thermal conductivity by combining specific heat capacity and density. The experimental method used a laser flash thermal conductivity meter to test the prepared material. The disc-shaped specimens were tested within a temperature range of room temperature to 300°C, with each temperature point held for 10 minutes followed by three repeated measurements. The standard was based on ASTM E1461-2013, and key parameters included a test temperature range of 25-300°C, a heating rate of 5°C / min, and laser pulse energy density controlled between 0.5-2.0 J / cm². 2Data processing employed the Cape-Lehman model to correct for the effects of finite pulse time and radiative heat loss, calculating the thermal conductivity λ = α × ρ × Cp, with the relative standard deviation of the test results required to be no more than 5%.

[0089] Thermal Expansion Coefficient Test Experiment: The test object is a rectangular sample (length ≥ 10 mm) of copper-diamond composite material. The purpose of the test is to determine the linear thermal expansion coefficient of the material at different temperatures. The test principle is based on the precise measurement of the length change of the sample during heating. The experimental method uses a thermomechanical analyzer (TMA). The sample with dimensions of 15 mm × 4 mm × 3 mm is placed in a quartz glass sample tube and heated from room temperature to 400 °C at a heating rate of 5 °C / min under a nitrogen protective atmosphere, with a contact force of 0.05 N applied. The standard is based on ASTM E831-2019, and key parameters include a test temperature range of 25-400 °C, a heating rate of 5 ± 0.1 °C / min, a gas flow rate of 50 mL / min, and a constant contact force. Data processing: The average linear thermal expansion coefficient is obtained by calculating ΔL / L0ΔT. Linear fitting is required within the temperature range of 50-300 °C, with a correlation coefficient R0. 2 ≥0.995.

[0090] Bending strength test experiment: The test object is a rectangular specimen of copper-diamond composite material. The purpose of the test is to evaluate the bending strength and elastic modulus of the material. The test principle is based on the stress-strain relationship of the specimen under a three-point bending loading mode. The experimental method uses a universal testing machine to conduct a three-point bending test. The specimen size is 50mm×10mm×5mm, the support span is 40mm, the loading rate is 1mm / min, and the test is conducted under the environmental conditions of room temperature and relative humidity of 50±5%. Key parameters include a span-to-thickness ratio of 8:1, a loading rate of 1.0±0.1mm / min, and a preload not exceeding 1% of the maximum load. Data processing is performed using the formula σf=3FL / 2bd. 2 Calculate the bending strength, E = L 3 m / 4bd 3 Calculate the bending modulus, where F is the maximum load, L is the span, b is the specimen width, d is the specimen thickness, and m is the slope of the initial linear segment of the load-deflection curve.

[0091] Microhardness Testing Experiment: The test object was a polished cross-section of a copper-containing diamond composite material. The purpose of the test was to determine the microhardness distribution of each phase in the composite material. The test principle is based on the indentation size formed by a Vickers microhardness tester diamond indenter indenting into the material surface under a specified load. The experimental method used a Vickers microhardness tester on the metallographically polished sample surface. Test loads of HV0.1, HV0.5, and HV1.0 were selected, with a holding time of 15 seconds. The hardness of the diamond particles, TiC interface layer, titanium-copper gradient layer, and copper alloy matrix were tested respectively. The standard was ASTM E384-2017, "Standard Test Method for Microindentation Hardness of Materials". Key parameters included a 136° pyramidal diamond indenter, a test environment temperature of 23±5℃, and a distance between test points not less than 2.5 times the diagonal length of the indentation. Data processing was performed using HV = 1.854F / d. 2 Calculate the Vickers hardness, where F is the test force (N) and d is the arithmetic mean of the lengths of the two diagonals of the indentation (mm). Test at least 10 points for each phase and calculate the mean and standard deviation.

[0092] Thermal Cycling Stability Test: The test subject is a copper-containing diamond composite material sample. The purpose of the test is to evaluate the dimensional stability and microstructural changes of the material under thermal cycling conditions. The test principle is based on the thermal stress effect caused by the difference in thermal expansion during repeated heating and cooling. The experimental method involves placing the sample in a programmable high-temperature furnace for thermal cycling tests, with the temperature cycling between -40℃ and +200℃. The heating rate is 10℃ / min, the cooling rate is 5℃ / min, and each temperature is held for 30 minutes as one cycle, for a total of 1000 cycles. The standard reference is ASTM E606-2019, "Standard Test Method for Strain-Controlled Fatigue Testing." Key parameters include temperature control accuracy of ±2℃, heating / cooling rate deviation not exceeding ±1℃ / min, holding time deviation not exceeding ±2 minutes, and a dry air atmosphere. Data processing evaluates thermal cycling stability by measuring the dimensional change rate and weight change rate of the sample before and after cycling, and by observing the microstructure. An intermediate test is required every 100 cycles.

[0093] The properties of the composite materials from Examples 1-4 and Comparative Examples 1-10 are summarized in Table 1. In Comparative Example 1, low-power plasma treatment (100W) resulted in insufficient removal of the oxide layer and impurities on the diamond surface, a decrease in the density of surface active sites, insufficient Ti-C reaction, and a significant decrease in interfacial bonding strength, leading to a comprehensive reduction in thermal conductivity, mechanical strength, and thermal cycling stability. In Comparative Example 2, the low-temperature short-time activation treatment (500℃, 15 minutes) resulted in insufficient formation of reactive active sites on the diamond surface, affecting the subsequent in-situ Ti-C reaction and reducing the quality of interfacial bonding. In Comparative Example 3... The low-temperature, low-speed deposition conditions (100℃, 1nm / min) resulted in insufficient density and poor adhesion of the gradient transition layer, loose bonding between the interface layer and the substrate, and a significant decrease in thermal conductivity and mechanical properties. In Comparative Example 4, improper sputtering power ratios led to an indistinct compositional gradient and uneven stress distribution, affecting the stress buffering effect and overall performance stability of the interface. In Comparative Example 5, the rapid heating process (5-8℃ / min) and short holding time (1 hour) resulted in insufficient Ti-C reaction, incomplete TiC interface layer formation, and compromised interface bonding strength and thermal conductivity. In Comparative Example 6, the low-pressure, low-speed deposition conditions... The low-temperature sintering conditions (30 MPa, 800 °C) resulted in a severely insufficient in-situ reaction of Ti-C, with the formed TiC interface layer thickness being only 40 nm, far below the 85-120 nm range of the previous examples. This significantly reduced the interfacial bonding strength and thermal conductivity. Insufficient post-treatment in Comparative Example 7 led to the inability to effectively eliminate residual stress, resulting in poor interfacial structural stability and a tendency for microcracks and interfacial delamination during thermal cycling. Comparative Example 8 lacked the crucial TiC interface layer, relying solely on the physical contact between the titanium-copper gradient layer and diamond. The interfacial bonding mechanism degenerated from chemical bonding to physical adsorption, significantly reducing interfacial thermal resistance. The increase in thermal conductivity and mechanical properties is significant; the simplified two-zone structure of Comparative Example 9 lacks the stress buffering effect of the intermediate gradient zone, and a smooth stress transition cannot be formed between the diamond and copper alloy matrix with large differences in thermal expansion coefficients, which easily leads to stress concentration and microcracks at the interface; Comparative Example 10 adopts a traditional powder mixing and sintering process without any interface engineering design, and there is no effective interface bonding mechanism between the diamond and copper alloy matrix. Mechanical mixing alone cannot form a continuous heat conduction channel, resulting in all performance indicators being significantly lower than those of the examples, demonstrating the key role of in-situ interface engineering technology.

[0094] Table 1 Summary of the properties of the composite materials from Examples 1-4 and Comparative Examples 1-10

[0095]

[0096]

[0097] pass Figure 1-4The systematic characterization analysis clearly shows that the copper-containing diamond composite material prepared in the embodiments of the present invention has significant technical advantages and performance improvement effects, wherein... Figure 1 The microstructure features of Example 2 show that a complete TiC interface layer and a titanium-copper gradient transition layer structure were successfully formed on the surface of the diamond particles. Line scan elemental distribution confirmed the orderly distribution and smooth transition of Ti, C and Cu elements, laying the microstructure foundation for excellent performance. Figure 2-4 The performance comparison results show that the thermal conductivity of all embodiments is in the range of 598-718 W / m·K, which is significantly higher than that of the comparative examples (285-582 W / m·K). Among them, Embodiment 2 reaches the highest value of 718 W / m·K, which is more than 23% higher than the best comparative example. At the same time, the coefficient of thermal expansion of the embodiments is controlled within 7.8-9.1×10. -6 Within the ideal range of / K, it is significantly lower than most comparative examples; in terms of mechanical properties, the bending strength of the examples is 445-512MPa, the elastic modulus is 245-318GPa, and the Vickers hardness is 218-275HV, all of which comprehensively exceed the corresponding indicators of the comparative examples; it is particularly noteworthy that in the thermal cycling stability test, all examples maintained an excellent level of 97.2-99.1%, while the highest of the comparative examples was only 93.2%, and the lowest dropped to 68.8%, which fully demonstrates the key role of the in-situ TiC interface layer and titanium-copper gradient transition layer design in improving the interface bonding strength, optimizing stress distribution, and enhancing thermal conductivity, and verifies the scientific nature and advancement of the technical solution of the present invention.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that any equivalent structural transformations made under the concept of the present invention and using the contents of the specification and drawings of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A copper-containing diamond composite material, characterized in that, It includes diamond particles, an in-situ TiC interface layer, a titanium-copper gradient transition layer, and a copper alloy matrix, with diamond particles dispersed in the copper alloy matrix as a reinforcing phase; A TiC interface layer and a titanium-copper gradient transition layer are sequentially formed on the surface of the diamond particles. The TiC interface layer is directly bonded to the diamond particles, and the titanium-copper gradient transition layer connects the TiC interface layer and the copper alloy matrix. The in-situ TiC interface layer has a sawtooth micromorphology, and the average thickness of the TiC interface layer is 85-120 nm. The total thickness of the titanium-copper gradient transition layer is 172-1600 nm; The titanium-copper gradient transition layer is divided into three functional regions according to the atomic percentage of Ti and Cu: a titanium-rich region adjacent to the TiC interface layer, a gradient region in the middle, and a copper-rich region connecting the copper alloy matrix. The volume fraction of diamond particles in the composite material is 20-50%, and the particle size of the diamond particles is 15-45 μm. The copper alloy matrix is ​​selected from one of the Cu-Cr, Cu-Zr, Cu-Be, and Cu-Ag copper alloys.

2. The copper-containing diamond composite material as described in claim 1, characterized in that, The titanium-rich region has a thickness of 52-500 nm, a Ti content of 80-95 at%, and a Cu content of 5-20 at%. This titanium-rich region thickness is the remaining thickness of the pre-fabricated titanium-rich region layer after the Ti-C in-situ reaction during the preparation process. The gradient region has a thickness of 60-700 nm, with the Ti content gradually decreasing from 80 at% to 20 at%, and the Cu content correspondingly increasing from 20 at% to 80 at%. The copper-rich region has a thickness of 60-500 nm, a Cu content of 80-95 at%, and a Ti content of 5-20 at.

3. The copper-containing diamond composite material as described in claim 1, characterized in that, The serrated TiC interface layer is formed by the in-situ reaction between the activated diamond particle surface and Ti atoms in the titanium-rich region, forming an interlocking structure with the titanium-copper gradient transition layer.

4. A method for preparing a copper-containing diamond composite material as described in any one of claims 1-3, characterized in that, Includes the following steps: S1. Directional pretreatment of diamond particle surface: Hydrogen plasma etching, directional activation and surface conditioning are used to obtain an active and smooth interface, which provides an ideal substrate for the uniform deposition of the subsequent titanium-copper gradient layer. S2. Pre-preparation of titanium-copper gradient transition layer: Based on the activated surface obtained in step S1, titanium-rich region, gradient region and copper-rich region are sequentially deposited on the surface of diamond particles using magnetron co-sputtering technology and segmented power-adjustable deposition method to form a pre-coated structure with gradient composition distribution. S3. Controlled high-temperature sintering composite: Through precise staged temperature control, the in-situ reaction of Ti-C is activated. At a sintering temperature of 870-920℃, Ti atoms in the titanium-rich region react with the activated diamond surface to generate a serrated TiC interface layer. S4. Post-processing, including controlled cooling and stabilization, to ensure the stability of the newly formed interface structure and eliminate reactive stress.

5. The method for preparing a copper-containing diamond composite material as described in claim 1, characterized in that, In step S1, the hydrogen plasma etching process involves treating the diamond particles in hydrogen plasma for 5-15 minutes at a temperature of 400-500°C and a plasma power of 200-600W to remove the oxide layer and impurities from the surface, exposing a clean and flat surface. Subsequently, a directional activation process is performed at 600-750°C in an inert atmosphere for 30-180 minutes to form a high density of reactive sites on the flat surface. Finally, the pretreatment parameters are precisely controlled through surface conditioning to form a uniform active distribution on the surface of the diamond particles that is conducive to the subsequent Ti-C reaction.

6. The method for preparing a copper-containing diamond composite material as described in claim 5, characterized in that, The substrate temperature of the magnetron co-sputtering technology in step S2 is 200-400℃ to ensure uniform deposition of a titanium-copper gradient transition layer on the flat surface of the activated diamond particles, and the sputtering deposition rate is 2-8nm / min. The segmented power-adjusted deposition method in step S2 includes first depositing a titanium-rich prefabricated layer with a titanium target power of 250-300W and a copper target power of 10-30W, controlling the prefabricated layer thickness within the range of 80-600nm. Then, gradient deposition is performed in 5-8 deposition segments, with the titanium target power decreasing from 250-300W to 50-80W and the copper target power increasing from 10-30W to 250-280W, controlling the deposition thickness within the range of 60-700nm. Finally, when depositing the copper-rich region, the copper target power is 250-300W and the titanium target power is 10-30W, controlling the deposition thickness within the range of 60-500nm. After the Ti-C in-situ reaction in step S3, some Ti atoms in the titanium-rich prefabricated layer are converted into a TiC interface layer.

7. The method for preparing a copper-containing diamond composite material as described in claim 5, characterized in that, The staged temperature control in step S3 includes the following stages: First, a pre-reaction nucleation process is initiated by slowly increasing the temperature to 750-800℃ at a rate of 1-3℃ / min and holding for 30-60 minutes. During this stage, the activated diamond particles begin to react initially with Ti atoms at the interface of the adjacent titanium-rich region. Second, the temperature is increased to 870-920℃ at a rate of 2-5℃ / min and held for 2-4 hours. During this stage, the Ti-C reaction proceeds fully, and TiC transitions from the flat interface to the titanium-copper gradient with a serrated microstructure. The first stage involves layer-wise growth at a rate of 20-40 nm / h to achieve an average thickness of 85-120 nm. The second stage involves cooling the temperature to below 500 °C at a rate of 3-8 °C / min and then allowing it to cool naturally to room temperature. During the second stage sintering process, a slower heating rate of 2-3 °C / min and a longer holding time of 3-4 hours are conducive to the full diffusion of Ti atoms to form a large serrated structure, while a faster heating rate of 4-5 °C / min and a shorter holding time of 2-2.5 hours restrict the diffusion to form a small serrated structure.

8. The method for preparing a copper-containing diamond composite material as described in claim 5, characterized in that, The controlled high-temperature sintering composite in step S3 adopts hot isostatic pressing or powder metallurgy sintering process, with a sintering pressure of 60-180MPa. Appropriate pressure is conducive to the full contact between the surface of the activated diamond particles and the titanium-rich area and the Ti-C reaction, promoting the formation of the serrated micro-morphology TiC interface layer. The holding time is 2-5 hours, and the sintering atmosphere is a vacuum or inert gas protection.

9. The application of the copper-containing diamond composite material as described in claim 1 in heat dissipation of electronic devices, characterized in that, The composite material is used as a heat dissipation substrate or heat sink for high-power electronic devices, with a thermal conductivity ≥600W / m·K.

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