High thermal conductivity diamond-copper composite material and preparation method thereof

Abstract

The application discloses a high-thermal-conductivity diamond-copper composite material and a preparation method thereof. The preparation method comprises the following steps: providing a target transition metal element, and depositing a metal coating on the surface of diamond particles by adopting an electroplating process or a chemical plating process; forming the diamond particles with the metal coating deposited on the surface into a diamond framework with pores by using a selective laser sintering or a fused deposition modeling technology; and placing the diamond framework and a copper matrix into a vacuum pressure infiltration furnace for infiltration treatment, so that the copper matrix fills the pores of the diamond framework, and the high-thermal-conductivity diamond-copper composite material is obtained. The preparation method can intelligently select material elements and addition amounts, improve material preparation efficiency and accuracy, and the prepared material has good thermal conductivity.

Description

Technical Field

[0001] This invention belongs to the technical field of thermally conductive material preparation, and particularly relates to a high thermal conductivity diamond-copper composite material and its preparation method. Background Technology

[0002] With the rapid development of high-end manufacturing fields such as artificial intelligence and new energy vehicles, the integration and operating efficiency of high-power electronic devices are continuously improving. The heat generated during their operation is increasing exponentially, and heat dissipation performance has become a core bottleneck restricting the release of device performance and the extension of its lifespan. Traditional heat dissipation materials such as pure copper and aluminum alloys have reached their theoretical thermal conductivity limits, making it difficult to meet the stringent requirements of efficient heat dissipation for AI chips, new energy vehicle power modules, and other applications.

[0003] Diamond-copper composites, combining the ultra-high thermal conductivity of diamond with the excellent thermal and electrical conductivity of copper, are considered key materials for overcoming the bottlenecks in high-end heat dissipation technology. However, existing preparation techniques have the following drawbacks: 1. Difficulty in controlling interfacial bonding: Diamond and copper have poor thermodynamic compatibility and extremely low wettability. Direct composites easily form weak bonding interfaces, becoming the main obstacle to heat transfer; 2. Poor performance stability: The amount of elements added depends on empirical judgment, which easily leads to the formation of brittle carbide phases or insufficient wettability, resulting in large fluctuations in the thermal conductivity of the composite material. Summary of the Invention

[0004] The purpose of this invention is to solve at least one problem in the prior art by proposing a high thermal conductivity diamond-copper composite material and its preparation method.

[0005] To achieve the above objectives, this invention proposes a method for preparing a high thermal conductivity diamond-copper composite material, comprising the following steps:

[0006] The target transition metal element is provided, and a coating of the transition metal element is deposited on the surface of diamond particles using electroplating or chemical plating processes. Selective laser sintering or fused deposition modeling technology is used to shape diamond particles with a transition metal element coating on the surface into a diamond framework with a porosity of 30%-60%. The diamond framework and copper matrix are placed in a vacuum pressure melting furnace and melted at a temperature of 1000℃-1200℃, a pressure of 5MPa-30MPa, and a holding time of 30min-120min to allow the copper matrix to fill the pores of the diamond framework, thus obtaining a high thermal conductivity diamond-copper composite material. Wherein, the absolute value of the binding energy between the target transition metal element and the diamond (111) facet and the copper (111) facet is >4eV / atom, the formation enthalpy of the carbide of the target transition metal element is <0, and the bonding mechanism between the target transition metal element and diamond and copper is at least one of covalent bond, metallic bond or ionic bond.

[0007] As an optional implementation, the target transition metal element includes at least one of Ti, Mo, Ni, and Co, and the thickness of the transition metal element coating is 0.5 μm-5 μm.

[0008] As an optional implementation, the parameters of the electroplating process are set as follows: electroplating current density of 2A / dm²-5A / dm², pH 4-6, and temperature of 40℃-60℃.

[0009] As an optional implementation, the diamond framework includes a heat dissipation channel structure. The selective laser sintering parameters are: laser power 150W-250W, scanning speed 1000mm / s-2000mm / s, and layer thickness 0.1mm-0.2mm. The channel structure is designed through topology optimization, and its shape includes, but is not limited to, honeycomb-shaped through-holes and dendritic through-holes. The parameter settings for selective laser sintering ensure the accuracy and quality of the framework forming.

[0010] As an optional implementation, the target transition metal element is obtained by screening using the following method: Collect electronic structure parameters, thermodynamic parameters, and interfacial performance parameters of transition metal elements with diamond (111) and copper (111) planes to establish a database of transition metal elements; High-throughput primary calculations were performed on the formation enthalpy of carbides of each transition metal element in the database, and the binding energy of the transition metal element with the diamond (111) facet and the copper (111) facet. Candidate transition metal elements were selected based on the calculation results. The formation enthalpy of candidate transition metal element carbides and the bonding energy and interface performance parameters of candidate transition metal elements with diamond (111) and copper (111) surfaces were collected. The wettability and interface bonding strength of candidate transition metal element coated diamond and copper were obtained experimentally. A machine learning model was trained to construct a diamond-copper wettability prediction model. The predicted value of the diamond-copper wettability prediction model was optimized by using the backpropagation algorithm. The candidate transition metal elements and their addition amounts were optimized by using a genetic algorithm to obtain the target transition metal elements and their addition amounts.

[0011] The screening process for candidate transition metal elements includes screening for thermodynamic stability, screening for interfacial bonding strength, and comprehensive screening.

[0012] Thermodynamic stability screening process is as follows: based on the enthalpy of formation calculation formula The formula for calculating the formation enthalpy of transition metal carbides is as follows: It is the total energy of the transition metal carbide unit cell. It is the average energy of a single transition metal atom in its most stable crystal structure. It is the average energy of a single carbon atom in diamond or graphite, selected by screening for negative enthalpy of formation (ΔH). f Transition metal elements with an enthalpy of formation of <0 and a large absolute value are selected. The energies in the formula are obtained through structural relaxation and static self-consistency calculations using first-principles software. The selection criteria are: a negative enthalpy of formation indicates that the carbides of the transition metal are thermodynamically stable and can form spontaneously; the larger the absolute value of the enthalpy of formation, the more stable the carbides are, and the less prone they are to decomposition. Transition metal elements with unstable carbides (positive or close to zero enthalpy of formation) are eliminated.

[0013] The interface bonding strength screening process is as follows: The transition metal elements selected based on thermodynamic stability are then analyzed according to the formula... Calculate the binding energy (E) between each transition metal element and the diamond (111) and copper (111) planes. bind ), in the formula It is the total energy of the constructed three-layer interface model of "diamond (111) facet - transition metal layer - copper (111) facet". It is the total energy of a single diamond (111) surface slab. The total energy of a single copper (111) slab is used to screen for transition metal elements that can form stable carbides and bond firmly to diamond or copper. All energies in the formula are calculated using first-principles calculation software. The screening criteria are: sufficiently high bonding energy with the diamond (111) surface (large negative value), and also sufficiently high bonding energy with the copper (111) surface (large negative value). A high bonding energy with diamond means that the transition metal element can act as an intermediate layer and adhere firmly to the diamond surface; a high bonding energy with copper means that the transition metal element can also adhere firmly to the copper substrate.

[0014] The comprehensive screening process is as follows: Based on the formation enthalpy of transition metal carbides and the binding energy of transition metal elements with diamond (111) and copper (111) planes, the transition metal elements with high values ​​in all three indicators (i.e., ranking in the top 10% or 20%) are selected as the final candidate transition metal elements.

[0015] The first-principles software used in the above screening process includes, but is not limited to, VASP or Quantum ESPRESSO.

[0016] The wettability and interfacial bonding strength of the candidate transition metal element coated diamond with copper were obtained through the following experimental procedure: A thin coating of candidate transition metal elements is deposited on the surface of diamond particles or diamond sheets using at least one of magnetron sputtering, chemical vapor deposition (CVD), or electroplating (each candidate transition metal element coating corresponds to one test sample). The wettability test was conducted using the seated drop method: Diamond substrates coated with various candidate transition metal coatings were placed in a high-temperature furnace, and pure copper blocks or copper droplets were placed on their surface. The substrates were heated to above the melting point of copper (e.g., 1150℃-1300℃) under vacuum or inert gas protection. The spreading process of the copper droplets on the diamond surface was recorded using a high-speed camera. By analyzing the droplet profile, the contact angle was measured. The smaller the contact angle, the better the wettability. The interfacial bonding strength is tested using indentation or tensile methods: a composite material sample is made by hot pressing and sintering coated diamond and copper matrix. Mechanical force is applied at the interface, and the critical load required for the interface to peel off is measured to obtain quantitative data such as interfacial shear strength or interfacial fracture toughness.

[0017] The diamond-copper wettability prediction model uses the theoretically calculated binding energy, interfacial energy, and formation enthalpy of candidate transition metal elements as input variables X, and the experimentally measured wettability (contact angle) and interfacial bonding strength as target output variables Y. It learns a function f using training data (X,Y) such that Y≈f(X), establishing a mapping relationship between the input variable X and the target output variable Y (e.g., the contact angle decreases approximately for every increase in binding energy). The diamond-copper wettability prediction model iteratively adjusts its internal parameters by minimizing the error (e.g., mean square error) between the predicted value Y' and the true value Y, ultimately enabling the function f to fit the experimental data well. The diamond-copper wettability prediction model is a machine learning-based regression model, constructed using a graph neural network (GNN) or a deep neural network (DNN).

[0018] The diamond-copper wettability prediction model can predict the wettability contact angle, interfacial bonding strength, thermal conductivity, and brittle phase formation probability of candidate transition metal elements based on their binding energy and the binding energy with diamond (111) and copper (111) surfaces and interfacial energy.

[0019] As an optional implementation, the transition metal element includes Cr, Ti, Mo, Ni, and Co. The electronic structure parameters of the transition metal element include atomic radius, electronegativity, and number of valence electrons. The thermodynamic parameters of the transition metal element include melting point, thermal melting point, and diffusion coefficient. The interface performance parameters of the transition metal element with the diamond (111) facet and the copper (111) facet include interface energy.

[0020] As an optional implementation, the process of optimizing the predicted values ​​of the diamond-copper wettability prediction model using the backpropagation algorithm is as follows: The predicted values ​​of the diamond-copper wettability prediction model and the wettability and interfacial bonding strength of candidate transition metal element coated diamonds with copper obtained experimentally are collected as a sample set. Then, based on the loss function formula... To calculate the loss value of the sample, in the formula, These are model predictions. These are the experimentally measured true values, N is the sample size, and Loss is the loss value; calculate the impact of each loss value (Loss) on the model parameters of the diamond-copper wettability prediction model. partial derivatives According to the formula Update the model parameters of the diamond-copper wettability prediction model. In the formula, It's the learning rate. These are the model parameters at the start of this iteration of the diamond-copper wettability prediction model. The parameters of the diamond-copper wettability prediction model have been iteratively adjusted and updated.

[0021] The model parameters of the diamond-copper wettability prediction model include weights. These weights determine the influence of a specific input feature on the prediction result. Reasonable weight settings allow the model to accurately capture physical laws such as higher binding energy leading to better wettability. However, unreasonable weight settings will cause the model's predictions to deviate from the experimental values. During the backpropagation algorithm optimization process, a larger loss value calculated by the loss function indicates a less accurate prediction of the diamond-copper wettability, as indicated by the partial derivatives. The purpose is to analyze which direction the model parameters should be adjusted to reduce the error. If a certain parameter causes the prediction error to increase (partial derivative is positive), the parameter is decreased; if it causes the error to decrease (partial derivative is negative), the parameter is increased. Through repeated iterations, the prediction error of the diamond-copper wettability prediction model will gradually decrease, eventually reaching a prediction accuracy of no less than 90%.

[0022] As an optional implementation, the genetic algorithm optimizes the candidate transition metal elements and their addition amounts as follows: A sample set of candidate transition metal elements with different addition amounts is randomly generated; the sample of each candidate transition metal element with its addition amount is substituted into the diamond-copper wettability prediction model to calculate the interfacial bonding strength, thermal conductivity, and brittle phase formation probability of each sample; according to the objective function formula Objective(fitness) = Max(interfacial bonding strength) + Max(thermal conductivity) - Min(brittle phase formation probability), the fitness of each sample is obtained, and samples with higher fitness values ​​are selected; the addition amounts of the samples with higher fitness values ​​are exchanged, and the samples are re-substituted into the above prediction model and objective function to calculate the fitness of new samples; the sample with the highest fitness is selected as the target transition metal element and its addition amount.

[0023] Max (interfacial bonding strength) aims to maximize the interfacial bonding strength between the diamond and copper coatings of the candidate transition metal element; a stronger bond results in better composite material performance. Max (thermal conductivity) aims to maximize the overall thermal conductivity of the composite material to ensure good heat dissipation. Min (probability of brittle phase formation) aims to minimize the probability of brittle phase formation at the interface (such as an excessively thick carbide layer), as brittle phases reduce the material's mechanical properties and reliability. The optimal addition amount found by the genetic algorithm corresponds to the individual with the highest fitness.

[0024] As an optional implementation, after the target transition metal element and its addition amount are confirmed, the solid solubility curve of carbon element in the target transition metal element, the phase equilibrium relationship between the target transition metal element and copper, and the thermodynamic stability of the carbide of the target transition metal element at the diamond-copper interface are obtained by using the CALPHAD method and Thermo-Calc or Pandat software, so as to verify the rationality of the addition amount of the target transition metal element.

[0025] The solid solubility curve of carbon in the target transition metal element was calculated using the CALPHAD method to clarify the saturated solid solubility of carbon by the target transition metal element under the target process temperature conditions. The rationality verification mechanism is as follows: If the amount of target transition metal element added is too low, carbon will quickly reach solid solution saturation in the target transition metal element, and the excess carbon will directly generate the corresponding brittle carbide phase at the diamond-target transition metal element interface, leading to the deterioration of interface toughness; if the amount of target transition metal element added is too high, although it can fully absorb carbon atoms at the interface, the excess target transition metal element will remain in the copper matrix to form a solid solution or intermetallic compound, which may adversely affect the thermal conductivity of the copper matrix. Therefore, the amount of target transition metal element added should be within a reasonable composition range, which can both fully absorb carbon atoms at the interface to form a target transition metal element carbide transition layer of appropriate thickness, and avoid deteriorating the matrix properties due to excessive target transition metal element residue.

[0026] By calculating the binary phase diagram of the target transition metal element-Cu, the possible phase types that may form in the target transition metal element-Cu system under different temperature and composition conditions were determined, including the liquid phase, Cu-target transition metal element solid solution, and compounds of copper and the target transition metal element. The rationality verification mechanism is as follows: if the amount of target transition metal element added falls into a certain composition range, resulting in the formation of a large amount of brittle Cu-target transition metal element intermetallic compounds, it will significantly deteriorate the interfacial bonding strength and thermal conductivity; therefore, this composition range should be excluded. On the other hand, an appropriate amount of target transition metal element reacts with Cu to form a thin layer of intermetallic compounds, which helps to improve the interfacial bonding strength, but its thickness and distribution morphology must be strictly controlled. Therefore, the amount of target transition metal element added should avoid the composition range that easily forms a large amount of harmful intermetallic compounds, and a composition range that is conducive to the formation of good interfacial bonding should be selected.

[0027] By calculating the Gibbs free energy change of the target transition metal carbide at the diamond-copper interface, the thermodynamic stability of the target transition metal carbide under the target process conditions and the possibility of interfacial reactions with diamond and copper are determined. The rationality verification mechanism is as follows: the formation enthalpy of the target transition metal carbide at the interface must be negative and have a sufficiently large absolute value to ensure that it does not decompose under high-temperature sintering and service conditions; at the same time, if the target transition metal carbide is too thermodynamically stable, it will continuously consume carbon atoms and target transition metal atoms, leading to excessive growth and thickening of the target transition metal carbide layer, which will become a thermally resistive and brittle layer, which is not conducive to the optimization of overall performance. Therefore, the amount of target transition metal added should allow the target transition metal carbide to exist stably at the interface but grow moderately, forming a thin and uniform transition layer, which achieves effective chemical bonding without affecting the interfacial thermal and mechanical properties due to excessive layer thickness.

[0028] The solid solubility curve clarifies the carbon carrying capacity of the target transition metal element, the phase equilibrium relationship reveals the possible phase types that may be formed between the target transition metal element and Cu, and the thermodynamic stability determines the existence form of the target transition metal element carbide at the interface. Only when the following conditions are met simultaneously can the amount of target transition metal element added be determined to be within a reasonable range: (1) the degree of carbon solid solubility is moderate, neither saturated nor excessive; (2) no harmful Cu-target transition metal element intermetallic compounds are formed; (3) the target transition metal element carbide exists stably but grows moderately, without forming an excessively thick brittle layer.

[0029] In summary, this rationality verification principle is essentially a comprehensive cross-validation method based on multiple thermodynamic criteria. By using the solid solubility curves, phase equilibrium relationships, and thermodynamic stability data calculated using the CALPHAD method, the range of addition amounts of the target transition metal element is constrained from three dimensions, ultimately determining an optimal addition range that can both form a stable carbide transition layer of the target transition metal element at the interface and avoid degrading the overall performance of the copper matrix.

[0030] As an optional implementation, the bonding mechanisms of each transition metal element with diamond and copper in the database, as well as the formation enthalpy of transition metal element carbides and the bonding energy of transition metal elements with diamond (111) and copper (111) planes, are obtained by analysis and calculation using VASP software or CASTEP software.

[0031] As an optional implementation, the diamond-copper wettability prediction model is constructed using a graph neural network or a deep neural network.

[0032] The present invention also proposes a high thermal conductivity diamond-copper composite material prepared according to the above preparation method, which can be used as a material for liquid cooling plates.

[0033] The beneficial effects of this invention are: 1. This application employs a diamond surface metallization + 3D printing + pressure melting process to achieve a tight bond between diamond and copper matrix, thereby increasing the density of the composite material, reducing interfacial thermal resistance, and improving the thermal conductivity and mechanical properties of the material.

[0034] 2. The preparation method of this application establishes a database of multiple transition metal elements, screens candidate transition metal elements through high-throughput first-principles analysis, and constructs a diamond-copper wettability prediction model by combining machine learning algorithms. This intelligently selects the target transition metal elements and their addition amounts for optimal interface modification. On the one hand, this ensures the strong interfacial bonding of the diamond-copper composite material and improves the thermal conductivity of the composite material. On the other hand, it achieves precision and standardization in material preparation, significantly improving the efficiency and controllability of material preparation.

[0035] 3. The preparation process of this application can shorten the research and development cycle of composite materials to 3-6 months. The density of the prepared diamond-copper composite material is not less than 99%, and the thermal conductivity is 600W / m·K-1000W / m·K, which can meet the heat dissipation requirements of high-end electronic devices.

[0036] The features and advantages of the present invention will be described in detail through embodiments and in conjunction with the accompanying drawings. Attached Figure Description

[0037] Figure 1 This is a flowchart of the diamond-copper composite material preparation process according to an embodiment of the present invention.

[0038] Figure 2 This is a morphology diagram of diamond particles with a Ti metal coating according to an embodiment of the present invention.

[0039] Figure 3 This is a morphology diagram of the diamond-copper composite material after sintering in an embodiment of the present invention. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0041] Example 1 See Figure 1 This embodiment provides a method for preparing a high thermal conductivity diamond-copper composite material, which is a composite material containing Ti element, and specifically includes the following steps: S1 Materials Database Construction: Based on the concept of materials genomics, an initial database was constructed containing the electronic structure parameters, thermodynamic parameters, and interfacial performance parameters of more than 50 transition metal elements, including Ti, Cr, V, Ni, Co, Mo, Hf, Ta, and W, as well as the interfacial performance parameters between transition metal elements and diamond (111) and copper (111) planes. The electronic structure parameters of each element include atomic radius, electronegativity, and number of valence electrons; the thermodynamic parameters include melting point, heat capacity, and diffusion coefficient; and the interfacial performance parameters include interfacial energy. Among them, Ti has an atomic radius of 147 pm, electronegativity of 1.54, valence electron number of 4, melting point of 1668℃, heat capacity of 25.06 J / (mol·K), and diffusion coefficient of approximately 1.2 × 10⁻¹⁰ in C at 1000℃. -12 m 2 / s; S2, based on high-throughput first principles, uses VASP software to perform high-throughput batch analysis and calculations on more than 50 transition metal elements in the database, and gradually narrows down the candidate range through a three-step screening process: S2.1 Thermodynamic Stability Screening: The formation enthalpy of carbides for all transition metal elements in the database was calculated, and elements with negative formation enthalpies and large absolute values ​​were screened. Calculations showed that the carbides of Sc, Ti, V, Cr, Ni, Cu, Mo, Hf, Ta, and W all had negative formation enthalpies, and these elements proceeded to the next round of screening. S2.2 Interface Bonding Strength Screening: The bonding energy between the transition metal elements obtained from the thermodynamic stability screening and the diamond (111) and copper (111) faces was calculated, and elements with absolute values ​​of bonding energy with both faces greater than 4 eV / atom were screened. Calculations showed that Ti, Cr, Ni, Mo, Co, and other elements met this condition and entered the next round of screening; S2.3 Comprehensive Screening: The multiple indicators (enthalpy of formation, binding energy with diamond, and binding energy with copper) from the first two rounds were comprehensively compared to screen out elements that performed well in all indicators. After comprehensive consideration, Ti ranked among the top in comprehensive score, and its specific calculation data are as follows: (a) Interface binding energy: The absolute value of the binding energy between Ti and the diamond (111) facet is 5.2 eV / atom, and the absolute value of the binding energy between Ti and the copper (111) facet is 4.8 eV / atom, both of which are greater than 4 eV / atom, indicating that Ti can adhere firmly to both the diamond surface and the copper matrix at the same time; (b) Electronic structure analysis: Through density of states (DOS) and charge density difference analysis, it was found that Ti mainly forms covalent bonds with diamond and mainly forms metallic bonds with the copper matrix, and the bonding mechanism is clear; (c) Thermodynamic stability: The enthalpy of formation of TiC is -184 kJ / mol, which is relatively large among all candidate elements, belonging to a highly stable carbide system.

[0042] S3 Artificial Intelligence Model Construction and Training: Using the binding energy, interfacial energy, and formation enthalpy of Ti as features, and combining experimentally measured wettability and interfacial bonding strength of Ti-coated diamond with copper as labels, a diamond-coated copper wettability prediction model was constructed using a graph neural network (GNN). The model parameters were optimized through backpropagation, resulting in a prediction accuracy of 92%. A genetic algorithm was used to perform multi-objective optimization on Ti. The calculation results of the objective function (Max(interfacial bonding strength) + Max(thermal conductivity) - Min(brittle phase formation probability)) showed that Ti performed excellently in improving interfacial bonding strength, maintaining thermal conductivity, and controlling the probability of brittle phase formation, making it a preferred additive element. The optimal mass ratio of Ti to diamond was 2:1. S4 Phase Diagram Calculation and Verification: Using the CALPHAD method and Thermo-Calc software, the solid solubility curve of carbon in Ti, the phase equilibrium relationship between Ti and copper, and the thermodynamic stability of TiC at the diamond-copper interface were obtained to verify the rationality of Ti and its addition amount. S4.1 According to the solid solubility curve of C in Ti, it is known that at 1000℃, the solid solubility of C in Ti is about 0.12 at.%, and the solid solubility gradually decreases as the temperature decreases; S4.2 Phase equilibrium relationship between Ti and Cu: Ti and Cu form a limited solid solution. At high temperatures, there is a certain miscibility region, while at low temperatures, intermetallic compound phases will appear. S4.3 Thermodynamic stability of interfacial reaction products: The high thermodynamic stability of TiC at the interface is verified, which is consistent with the screening results of the artificial intelligence model, proving the reliability of the addition of Ti element; S5 Diamond Surface Metallization Treatment: A Ti coating is deposited on the surface of diamond particles using an electroplating process. The Ti coating thickness is 2μm, and the required bonding strength is ≥50MPa. The mass ratio of Ti to diamond is 2:1. The electroplating process parameters are as follows: electroplating current density 2A / dm², pH 4.5, and temperature 50℃. The morphology of the metallized diamond particles is as follows. Figure 2 As shown; S6 3D printing to prepare diamond framework: Selective laser sintering (SLS) technology is used to form diamond powder with Ti coating on the surface into a diamond framework with 50% porosity and honeycomb channel structure. The process parameters of selective laser sintering are set as follows: laser power of 200W, scanning speed of 1500mm / s, and layer thickness of 0.15mm. S7. A diamond framework and a copper matrix were placed in a vacuum pressure infiltration furnace and infiltrated at a temperature of 1000℃, a pressure of 15MPa, and a holding time of 60min. This infiltration process completely filled the pores of the framework with copper, resulting in a high thermal conductivity diamond-copper composite material. The morphology of the prepared diamond-copper composite material is as follows. Figure 3 As shown.

[0043] The high thermal conductivity diamond-copper composite material of this embodiment has a density of 99.5% and a thermal conductivity of 780 W / (m·K).

[0044] Example 2 This embodiment provides a method for preparing a high thermal conductivity diamond-copper composite material, which is a Ni-containing composite material, and specifically includes the following steps: S1 Materials Database Construction: Based on the concept of materials genomics, an initial database was constructed containing the electronic structure parameters, thermodynamic parameters, and interfacial performance parameters of more than 50 transition metal elements such as Ni, Ti, Cr, V, Co, Mo, Hf, Ta, and W, as well as the interfacial performance parameters between transition metal elements and diamond (111) and copper (111) planes. The electronic structure parameters of each element include atomic radius, electronegativity, and number of valence electrons; the thermodynamic parameters include melting point, heat capacity, and diffusion coefficient; and the interfacial performance parameters include interfacial energy. Among them, the electronic structure parameters of Ni include an atomic radius of 124 pm, electronegativity of 1.91, and number of valence electrons of 10; and the thermodynamic parameters of Ni include a melting point of 1455℃, a heat capacity of 26.07 J / (mol·K), and a diffusion coefficient of approximately 2.5 × 10⁻⁶ in Cu at 1000℃. -13 m 2 / s, as well as interface performance parameters such as the bonding energy and interface energy between Ni and diamond (111) facet and copper (111) facet; Based on high-throughput first principles, S2 uses CASTEP software to perform high-throughput batch analysis and calculations on more than 50 transition metal elements in the database, and gradually narrows down the candidate range through a three-step screening process: S2.1 Thermodynamic Stability Screening: The formation enthalpy of carbides for all transition metal elements in the database was calculated, and elements with negative formation enthalpies and large absolute values ​​were screened. Calculations showed that the carbides of Sc, Ti, V, Cr, Ni, Cu, Mo, Hf, Ta, and W all had negative formation enthalpies, and these elements proceeded to the next round of screening. S2.2 Interface Bonding Strength Screening: The bonding energy between the transition metal elements obtained from the thermodynamic stability screening and the diamond (111) and copper (111) faces was calculated, and elements with absolute values ​​of bonding energy with both faces greater than 4 eV / atom were screened. Calculations showed that Ti, Cr, Ni, Mo, Co, and other elements met this condition and entered the next round of screening; S2.3 Comprehensive Screening: The multiple indicators (enthalpy of formation, binding energy with diamond, and binding energy with copper) from the first two rounds were comprehensively compared to screen out elements that performed well in all indicators. After comprehensive consideration, Ni ranked among the top in comprehensive score, and its specific calculation data are as follows: (a) Interface binding energy: The absolute value of the binding energy between Ni and the diamond (111) surface is 4.5 eV / atom, and the absolute value of the binding energy between Ni and the copper (111) surface is 5.1 eV / atom, both of which are greater than 4 eV / atom, indicating that Ni can adhere firmly to both the diamond surface and the copper matrix at the same time; (b) Electronic structure analysis: Through density of states (DOS) and charge density difference analysis, it was found that Ni mainly forms metallic bonds and weak covalent bonds with diamond, and mainly forms metallic bonds with the copper matrix, with good bonding performance; (c) Thermodynamic stability: The enthalpy of formation of Ni3C is -39 kJ / mol, which is less than 0, belonging to a stable carbide system, which meets the screening requirements; S3 Artificial Intelligence Model Construction and Training: Using Ni's binding energy, interfacial energy, and Ni3C formation enthalpy data as features, and combining experimentally measured wettability and interfacial bonding strength between Ni-coated diamond and copper as labels, a diamond-coated copper wettability prediction model was constructed using a deep neural network (DNN). After training and optimization, the model's prediction accuracy reached 93%, meeting the requirement of ≥90%. A genetic algorithm was used to perform multi-objective optimization on Ni. The calculation results of the objective function (Max(interfacial bonding strength) + Max(thermal conductivity) - Min(probability of brittle phase formation)) showed that Ni performed excellently in improving interfacial bonding strength, ensuring thermal conductivity, and reducing the probability of brittle phase formation, making it a preferred additive element. The optimal mass ratio of Ni to diamond was 1.5:1. S4 Phase Diagram Calculation and Verification: Using the CALPHAD method and Pandat software, the solid solubility curve of carbon in Ni, the phase equilibrium relationship between Ni and copper, and the thermodynamic stability of Ni3C at the diamond-copper interface were obtained, verifying the rationality of Ni element and its addition amount. S4.1 According to the solid solubility curve of C in Ni, it is known that at 1000℃, the solid solubility of C in Ni is about 0.2 at.%, and temperature has a significant effect on solid solubility. S4.2 Phase equilibrium relationship between Ni and Cu: Ni and Cu form an infinite solid solution, which can maintain a single-phase solid solution structure throughout the entire composition range, which is beneficial to the improvement of interfacial bonding performance; S4.3 Thermodynamic stability of interfacial reaction products: The good thermodynamic stability of Ni3C at the interface is verified, which is consistent with the screening results of the artificial intelligence model, proving the rationality of Ni element addition; S5 Diamond Surface Metallization Treatment: A Ni coating is deposited on the surface of diamond particles using a chemical plating process. The coating thickness is 3μm, and the required bonding strength is ≥50MPa. The mass ratio of Ni to diamond is 1.5:1. When the chemical plating temperature is 85℃, the pH value is 8.5, and the complexing agent concentration is 0.1 mol / L, the coating uniformity is good, and the thickness deviation is <±10%. S6 3D printing to prepare diamond framework: The fused deposition modeling (FDM) process is used to form diamond powder with a Ni coating on the surface into a diamond framework with 40% porosity and dendritic flow channel structure. The parameters of the fused deposition modeling process are set as follows: printing temperature is 220℃, printing speed is 60mm / s, and layer thickness is 0.2mm. S7 The diamond framework and copper matrix are placed in a vacuum pressure melting furnace and melted at a melting temperature of 1150℃, a pressure of 20MPa, and a holding time of 75min to achieve melting treatment, so that the copper matrix completely fills the pores of the framework, resulting in a high thermal conductivity diamond-copper composite material.

[0045] The high thermal conductivity diamond-copper composite material of this embodiment has a density of 99.5% and a thermal conductivity of 894 W / (m·K).

[0046] Example 3 This embodiment provides a method for preparing a high thermal conductivity diamond-copper composite material. The high thermal conductivity diamond-copper composite material is a diamond-copper composite material containing Mo and Co elements, and specifically includes the following steps: S1 Materials Database Construction: Based on the concept of materials genomics, an initial database was constructed containing the electronic structure parameters, thermodynamic parameters, and interfacial performance parameters of more than 50 transition metal elements, including Ti, Cr, V, Ni, Co, Mo, Hf, Ta, and W, as well as the interfacial performance parameters between transition metal elements and diamond (111) and copper (111) planes. The electronic structure parameters of each element include atomic radius, electronegativity, and number of valence electrons; the thermodynamic parameters include melting point, heat capacity, and diffusion coefficient; and the interfacial performance parameters include interfacial energy. Among them, the atomic radius of Mo is 139 pm, electronegativity is 2.16, and the number of valence electrons is 6; the atomic radius of Co is 125 pm, electronegativity is 1.88, and the number of valence electrons is 9; the melting point of Mo is 2620℃, the heat capacity is 24.06 J / (mol·K), and the diffusion coefficient is approximately 8.3 × 10⁻⁶ in Cu at 1000℃. -14 m 2 Co has a melting point of 1495℃, a heat capacity of 24.81 J / (mol·K), and a diffusion coefficient of approximately 1.8 × 10⁻⁶ in Cu at 1000℃. -13 m 2 / s; S2, based on high-throughput first principles, uses VASP software to perform high-throughput batch analysis and calculations on more than 50 transition metal elements in the database, and gradually narrows down the candidate range through a three-step screening process: S2.1 Thermodynamic Stability Screening: The formation enthalpy of carbides for all transition metal elements in the database was calculated, and elements with negative formation enthalpies and large absolute values ​​were screened. Calculations showed that the carbides of Sc, Ti, V, Cr, Ni, Cu, Mo, Hf, Ta, and W all had negative formation enthalpies, and these elements proceeded to the next round of screening. S2.2 Interface Bonding Strength Screening: The bonding energy between the transition metal elements obtained from the thermodynamic stability screening and the diamond (111) and copper (111) faces was calculated, and elements with absolute values ​​of bonding energy with both faces greater than 4 eV / atom were screened. Calculations showed that Ti, Cr, Ni, Mo, Co, and other elements met this condition and entered the next round of screening; S2.3 Comprehensive Screening: Multiple indicators from the first two rounds (enthalpy of formation, binding energy with diamond, and binding energy with copper) were comprehensively compared to screen for elements that performed well across all indicators. After comprehensive consideration, Mo and Co each had advantages in different indicators—Mo had a higher binding energy with diamond (forming strong covalent bonds), while Co had a higher binding energy with copper (forming good metallic bonds). Their synergistic and complementary effects were expected to achieve better interfacial bonding. Therefore, Mo+Co was selected as the preferred additive element, with an optimal mass ratio of Mo to Co of 3:1 and an optimal mass ratio of Mo+Co to diamond of 2:1. The specific calculation data for Mo and Co elements during the above screening process are as follows: (a) Interfacial bonding energy: The absolute value of the bonding energy between Mo and the diamond (111) facet is 4.8 eV / atom, and the absolute value of the bonding energy between Mo and the copper (111) facet is 4.3 eV / atom; the absolute value of the bonding energy between Co and the diamond (111) facet is 4.6 eV / atom, and the absolute value of the bonding energy between Co and the copper (111) facet is 5.0 eV / atom. Both are greater than 4 eV / atom. (a) eV / atom, meeting the screening criteria; (b) Electronic structure analysis: Through density of states (DOS) and charge density difference analysis, it was found that Mo mainly forms covalent bonds with diamond and mainly forms metallic bonds with the copper matrix; Co mainly forms metallic bonds and weak covalent bonds with diamond and mainly forms metallic bonds with the copper matrix. Mo's strong carbide forming ability is beneficial to the bonding on the diamond side, and Co's good wettability is beneficial to the diffusion and bonding on the copper side. The synergistic effect of the two can optimize the overall interface performance; (c) Thermodynamic stability: The formation enthalpy of Mo2C is -49 kJ / mol, and the formation enthalpy of Co3C is -39 kJ / mol, both less than 0, belonging to a stable carbide system, meeting the screening requirements; S3 Artificial Intelligence Model Construction and Training: The binding energy, interfacial energy, and formation enthalpy of the corresponding carbides (Mo2C and Co3C) of Mo and Co elements were used as features. Combined with experimentally measured wettability and interfacial bonding strength of Mo+Co coated diamond with copper, these data were incorporated into the training set. A graph neural network (GNN) was used to construct a diamond-copper wettability prediction model. After training and optimization, the model's prediction accuracy reached 94%. A genetic algorithm was used to perform multi-objective optimization of Mo and Co elements, determining the optimal addition ratio of Mo to Co to be 3:2. The objective function calculation results showed that this composite additive element has significant advantages in improving interfacial bonding strength, ensuring thermal conductivity, and reducing the probability of brittle phase formation. S4 Phase Diagram Calculation and Verification: Using the CALPHAD method and Thermo-Calc software, the solid solubility curves of carbon in Mo and Co, the phase equilibrium relationship between Mo and Co and copper, and the thermodynamic stability of Mo2C and Co3C at the diamond-copper interface were obtained to verify the rationality of Mo and Co elements and their addition amounts. S4.1 According to the solid solubility curves of C in Mo and Co, it is known that at 1000℃, the solid solubility of C in Mo is about 0.08 at.% and the solid solubility in Co is about 0.2 at.%. Temperature has a certain influence on the solid solubility of both. S4.2 Phase equilibrium relationship between Mo, Co and Cu: Mo and Cu form a limited solid solution, while Co and Cu form an unlimited solid solution. When Mo+Co is added in combination, a relatively stable solid solution system can be formed within a certain composition range, which is beneficial to interfacial bonding. S4.3 Thermodynamic stability of interfacial reaction products: It was verified that Mo2C and Co3C both have high thermodynamic stability at the interface, which is consistent with the screening results of artificial intelligence model, proving the reliability of Mo+Co composite addition; S5 Diamond Surface Metallization Treatment: A Mo+Co composite coating is deposited on the surface of diamond particles using an electroplating process. The coating thickness is 3.5μm, and the required bonding strength is ≥50MPa. The mass ratio of Mo to Co is 3:1, and the total mass ratio of Mo+Co elements to diamond is 2:1. The electroplating process parameters are set as follows: electroplating current density is 2.5 A / dm², pH is 5.0, and temperature is 55℃. S6 3D printing fabrication of diamond framework: Selective laser sintering (SLS) technology is used to shape surface-metallized diamond powder into a diamond framework with 55% porosity and a mixed channel structure (honeycomb + dendritic). The process parameters of selective laser sintering are set as follows: laser power of 220W, scanning speed of 1800mm / s, and layer thickness of 0.12mm. S7 The diamond framework and copper matrix are placed in a vacuum pressure melting furnace and melted at a melting temperature of 1200℃, a pressure of 25MPa, and a holding time of 90min to completely fill the pores of the framework with the copper matrix, thus obtaining a high thermal conductivity diamond-copper composite material.

[0047] The high thermal conductivity diamond-copper composite material of this embodiment has a density of 99.6% and a thermal conductivity of 967 W / (m·K).

[0048] The above embodiments are illustrative of the present invention and are not intended to limit the present invention. Any simple modifications to the present invention are within the scope of protection of the present invention.

Claims

1. A method for preparing a high thermal conductivity diamond-copper composite material, characterized in that: It includes the following steps: The target transition metal element is provided, and a coating of the transition metal element is deposited on the surface of diamond particles using electroplating or chemical plating processes. Selective laser sintering or fused deposition modeling technology is used to shape diamond particles with a transition metal element coating on the surface into a diamond framework with a porosity of 30%-60%. The diamond framework and copper matrix are placed in a vacuum pressure melting furnace and melted at a temperature of 1000℃-1200℃, a pressure of 5MPa-30MPa, and a holding time of 30min-120min to allow the copper matrix to fill the pores of the diamond framework, thus obtaining a high thermal conductivity diamond-copper composite material. Wherein, the absolute value of the binding energy between the target transition metal element and the diamond (111) facet and the copper (111) facet is >4 eV / atom, the formation enthalpy of the carbide of the target transition metal element is <0, and the bonding mechanism between the target transition metal element and diamond and copper is at least one of covalent bond, metallic bond or ionic bond.

2. The preparation method of the high thermal conductivity diamond-copper composite material as described in claim 1, characterized in that: The target transition metal element includes at least one of Ti, Mo, Ni, and Co, and the thickness of the transition metal element coating is 0.5 μm-5 μm.

3. The preparation method of the high thermal conductivity diamond-copper composite material as described in claim 1, characterized in that: The parameters for the electroplating process are set as follows: electroplating current density of 2A / dm²-5A / dm², pH 4-6, and temperature of 40℃-60℃.

4. The method for preparing the high thermal conductivity diamond-copper composite material as described in claim 1, characterized in that: The diamond skeleton has a heat dissipation channel structure inside. The parameters of the selective laser sintering are laser power of 150W-250W, scanning speed of 1000mm / s-2000mm / s, and layer thickness of 0.1mm-0.2mm.

5. The method for preparing the high thermal conductivity diamond-copper composite material as described in claim 1, characterized in that: The target transition metal element was obtained by screening using the following method: Collect electronic structure parameters, thermodynamic parameters, and interfacial performance parameters of transition metal elements with diamond (111) and copper (111) planes to establish a database of transition metal elements; High-throughput primary calculations were performed on the formation enthalpy of carbides of each transition metal element in the database, and the binding energy of the transition metal element with the diamond (111) facet and the copper (111) facet. Candidate transition metal elements were selected based on the calculation results. The formation enthalpy of candidate transition metal element carbides and the bonding energy and interface performance parameters of candidate transition metal elements with diamond (111) and copper (111) surfaces were collected. The wettability and interface bonding strength of candidate transition metal element coated diamond and copper were obtained experimentally. A machine learning model was trained to construct a diamond-copper wettability prediction model. The predicted value of the diamond-copper wettability prediction model was optimized by using the backpropagation algorithm. The candidate transition metal elements and their addition amounts were optimized by using a genetic algorithm to obtain the target transition metal elements and their addition amounts.

6. The method for preparing the high thermal conductivity diamond-copper composite material as described in claim 5, characterized in that: The transition metal elements include Cr, Ti, Mo, Ni, and Co. The electronic structure parameters of the transition metal elements include atomic radius, electronegativity, and number of valence electrons. The thermodynamic parameters of the transition metal elements include melting point, thermal melting point, and diffusion coefficient. The interfacial performance parameters of the transition metal elements with diamond (111) and copper (111) surfaces include interfacial energy.

7. The method for preparing the high thermal conductivity diamond-copper composite material as described in claim 5, characterized in that: The process of optimizing the predicted values ​​of the diamond-copper wettability prediction model using the backpropagation algorithm is as follows: The predicted values ​​of the diamond-copper wettability prediction model and the wettability and interfacial bonding strength of diamond coated with candidate transition metal elements obtained experimentally are collected as a sample set. Then, the loss function formula is applied... To calculate the loss value of the sample, in the formula, These are model predictions. These are the experimentally measured true values, N is the sample size, and Loss is the loss value; calculate the impact of each loss value (Loss) on the model parameters of the diamond-copper wettability prediction model. partial derivatives According to the formula Update the model parameters of the diamond-copper wettability prediction model. In the formula, It is the learning rate. These are the model parameters at the start of this iteration of the diamond-copper wettability prediction model. These are the updated model parameters for the diamond-copper wettability prediction model after iterative adjustments.

8. The method for preparing the high thermal conductivity diamond-copper composite material as described in claim 5, characterized in that: The genetic algorithm optimizes the candidate transition metal elements and their addition amounts as follows: a sample set of candidate transition metal elements with different addition amounts is randomly generated; the sample of each candidate transition metal element with different addition amounts is substituted into the diamond-copper wettability prediction model to calculate the interfacial bonding strength, thermal conductivity and brittle phase formation probability of each sample. According to the objective function formula Objective (fitness) = Max (interfacial bonding strength) + Max (thermal conductivity) - Min (probability of brittle phase formation), the fitness of each sample is obtained, and the samples with the highest fitness values ​​are selected. The addition values ​​of the samples with the highest fitness values ​​are exchanged, and the new fitness values ​​are calculated by substituting them into the above prediction model and objective function. The sample with the highest fitness is selected as the target transition metal element and addition amount.

9. The method for preparing the high thermal conductivity diamond-copper composite material as described in claim 5, characterized in that: After confirming the target transition metal element and its addition amount, the solid solubility curve of carbon in the target transition metal element, the phase equilibrium relationship between the target transition metal element and copper, and the thermodynamic stability of the carbide of the target transition metal element at the diamond-copper interface are obtained by using the CALPHAD method and Thermo-Calc or Pandat software, so as to verify the rationality of the addition amount of the target transition metal element.

10. A high thermal conductivity diamond-copper composite material prepared by the preparation method according to any one of claims 1 to 9.

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