High Thermal Conductivity Diamond–Copper Composites Prepared via Hot Pressing with Tungsten–Coated Interfacial Layer Optimization
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2025-08-19 |
| Journal | Materials |
| Authors | Qiang Wang, Zhijie Ye, Lei Liu, Jie Bai, Yuning Zhao |
| Institutions | Ji Hua Laboratory, Harbin Institute of Technology |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”- Peak Thermal Conductivity (TC): The fabricated diamond-copper composite achieved 640 W/(mK) at 50 vol% diamond content, representing the highest reported TC for hot-press sintered (HPS) composites with diamond content not exceeding 50%.
- Interface Engineering: Tungsten (W) was deposited via magnetron sputtering and subsequently annealed at 1100 °C for 2 hours to form a carbide transition layer (W2C and WC).
- Optimal Composition: The highest TC was achieved when the interfacial layer consisted of 2 wt.% W, 92 wt.% WC, and 6 wt.% W2C.
- Microstructural Improvement: Annealing for 2 hours minimized the formation of low-conductivity amorphous carbon (a-C) regions and promoted a dense, ordered crystalline carbide structure, significantly reducing interfacial thermal resistance.
- Interfacial Thermal Conductance (ITC): The optimal 2-hour annealed sample exhibited a peak ITC between 36 and 56 MW/(m2K), a substantial increase from the initial 9 MW/(m2K) (0h annealing).
- Theoretical Validation: Acoustic Mismatch Model (AMM) and Diffusion Mismatch Model (DMM) calculations identified the optimal theoretical interface structure for phonon regulation as Diamond/W2C/WC/W2C/Cu.
- Fabrication Method: Hot-press sintering (HPS) was confirmed as an effective method for producing high-performance composites, offering advantages in process control and uniformity over other methods like SPS or GPI.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Peak Thermal Conductivity (TC) | 640 | W/(mK) | 50 vol% diamond, 2h annealing |
| Diamond Volume Fraction | 50 | vol% | Optimized content for peak TC |
| Diamond Particle Size | 400 | µm | Substrate material (HHD-90) |
| W Coating Thickness | 200 | nm | Deposited via magnetron sputtering |
| Annealing Temperature | 1100 | °C | Vacuum tube furnace |
| Annealing Time (Optimal) | 2 | h | Yielded peak TC |
| Annealing Vacuum Pressure | 5 x 10-4 | Pa | Maintained during heat treatment |
| Peak Interfacial TC (H-J Model) | 56 | MW/(m2K) | Calculated for 2h annealed composite |
| Lowest Interfacial TC (a-C/Diamond) | 2.59 | MW/(m2K) | Calculated via AMM |
| W2C/WC Interfacial TC | 11,400 | MW/(m2K) | Calculated via AMM (highest internal carbide ITC) |
| Diamond Intrinsic TC (Calculated) | 1717 | W/(mK) | Based on 147 ppm Nitrogen content |
| Optimal Interface Composition | 92% WC, 6% W2C, 2% W | wt.% | Composition after 2h annealing |
| HPS Composite Diameter | 30 | mm | Initial HPS sample size |
Key Methodologies
Section titled “Key Methodologies”-
Diamond Cleaning and Preparation:
- Single-crystal diamond particles (400 µm) were sequentially cleaned using nitric acid, sodium hydroxide, acetone, and anhydrous ethanol.
- Ultrasonic cleaning was applied to remove surface impurities before drying.
-
Tungsten (W) Coating Deposition:
- W coating (200 nm average thickness) was deposited onto the diamond particles using pulsed magnetron sputtering in an Argon atmosphere.
- Particles were placed on a tilted rotating plate to ensure uniform coverage.
-
Vacuum Annealing (Carbide Formation):
- Coated particles were annealed at 1100 °C for varying durations (0 to 6 h) in a tube furnace.
- A high vacuum (5 x 10-4 Pa) was maintained to prevent oxidation.
- Annealing promoted the conversion of W into W2C and WC, with 2 hours yielding the optimal carbide ratio (92% WC, 6% W2C).
-
Copper Plating:
- Annealed diamond particles were activated and sensitized.
- A copper layer was chemically deposited onto the metallized diamond surfaces using a rotary evaporator.
-
Hot-Press Sintering (HPS):
- The coated diamond powder was consolidated using HPS to form a dense composite material (50 vol% diamond).
- The resulting composite was 30 mm in diameter and 1.5 mm thick, subsequently cut into 12.7 mm discs for characterization.
-
Characterization and Modeling:
- XRD, SEM, and Raman spectroscopy were used for phase identification and morphology analysis.
- Thermal diffusivity was measured using the LFA467 HyperFlash method.
- Thermal conductivity was calculated from density, specific heat, and diffusivity.
- Interfacial thermal conductance was theoretically analyzed using the Acoustic Mismatch Model (AMM) and the Diffusion Mismatch Model (DMM).
Commercial Applications
Section titled “Commercial Applications”The high thermal conductivity and robust interface bonding achieved by these diamond-copper composites make them ideal for demanding thermal management roles in high-tech sectors:
- High-Power Electronic Devices: Used as heat sinks and spreaders for high-density components where traditional materials are inadequate.
- Aerospace and Defense: Applications requiring lightweight materials with exceptional thermal stability and dissipation capabilities.
- Mobile Chip Manufacturing: Thermal management solutions for high-integration, high-power density mobile processors and chips.
- Thermal Management Systems: General use in cooling systems where efficient heat transfer is critical (e.g., high-frequency communications, radar).
- Thermoelectric Conversion: Potential application in systems requiring efficient heat flow regulation.
View Original Abstract
Diamond-copper composites, due to their exceptional thermal conductivity, hold significant potential in the field of electronic device thermal management. Hot-press sintering is a promising fabrication technique with industrial application prospects; however, the thermal conductivity of composites prepared by this method has yet to reach optimal levels. In this study, tungsten was deposited on the surface of diamond particles by magnetron sputtering as an interfacial transition layer, and hot-press sintering was employed to fabricate the composites. The findings reveal that with prolonged annealing time, tungsten gradually transformed into W2C and WC, significantly enhancing interfacial bonding strength. When the diamond volume content was 50% and the interfacial coating consisted of 2 wt.% W, 92 wt.% WC, and 6 wt.% W2C, the composite exhibited a thermal conductivity of 640 W/(m·K), the highest value reported among hot-press sintered composites with diamond content below 50%. Additionally, the AMM (Acoustic Mismatch Model) and DMM (Diffusion Mismatch Model) models were utilized to calculate the interfacial thermal conductance between different phases, identifying the optimal interfacial structure as diamond/W2C/WC/W2C/Cu. This composite material shows potential for application in high-power electronic device cooling, thermal management systems, and thermoelectric conversion, providing a more efficient thermal dissipation solution for related devices.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
Section titled “References”- 2018 - Theoretical modelling for interface design and thermal conductivity prediction in diamond/Cu composites [Crossref]
- 2021 - Reinforcement size effect on thermal conductivity in Cu-B/diamond composite [Crossref]
- 2020 - High-Temperature Thermal Conductivity and Thermal Cycling Behavior of Cu-B/Diamond Composites [Crossref]
- 2012 - Preparation of Si-diamond-SiC composites by in-situ reactive sintering and their thermal properties [Crossref]
- 2018 - Combining Cr pre-coating and Cr alloying to improve the thermal conductivity of diamond particles reinforced Cu matrix composites [Crossref]
- 2018 - Enhanced thermal conductivity in Cu/diamond composites by tailoring the thickness of interfacial TiC layer [Crossref]