An Investigation on the Spark Plasma Sintering Diffusion Bonding of Diamond/Cu Composites with a Cr Interlayer
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-12-10 |
| Journal | Materials |
| Authors | Ying Zhou, Daochun Hu, Minghe Chen, Taowen Wu, Jindong Ouyang |
| Institutions | Aviation Industry Corporation of China (China), Nanjing University of Aeronautics and Astronautics |
| Citations | 4 |
| Analysis | Full AI Review Included |
An Investigation on the Spark Plasma Sintering Diffusion Bonding of Diamond/Cu Composites with a Cr Interlayer
Section titled âAn Investigation on the Spark Plasma Sintering Diffusion Bonding of Diamond/Cu Composites with a Cr InterlayerâExecutive Summary
Section titled âExecutive SummaryâThis research successfully optimized the Spark Plasma Sintering (SPS) diffusion bonding of high thermal conductivity (TC) diamond/Cu composites using a Chromium (Cr) interlayer, critical for advanced thermal management applications.
- Core Achievement: High-quality, defect-free joints were fabricated by optimizing interlayer thickness, temperature, time, and pressure via SPS.
- Interfacial Mechanism: The Cr interlayer chemically reacts with diamond (C) to form stable Cr3C2 carbides, transitioning the interface from weak mechanical contact to strong chemical bonding.
- Optimal Parameters: The best joint quality was achieved using a 10 ”m Cr interlayer, bonded at 810 °C for 60 min under 10 MPa pressure.
- Mechanical Performance: The optimal joint exhibited a maximum shear strength of 139.89 MPa, nearly double the strength achieved at 720 °C.
- Thermal Performance: The thermal conductivity (TC) of the optimal joint reached 700.97 W/(m·K), retaining 85.62% of the base diamond/Cu composite TC (818.67 W/(m·K)).
- Process Control: Increasing bonding temperature and holding time effectively promoted atomic diffusion, eliminating microcracks and voids at the interface.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Base Composite TC | 818.67 | W/(m·K) | Diamond/Cu composite (60 vol% diamond) |
| Optimal Joint TC | 700.97 | W/(m·K) | Achieved at 810 °C, 60 min, 10 MPa, 10 ”m Cr |
| TC Retention Rate | 85.62 | % | Relative to the base material TC |
| Maximum Shear Strength | 139.89 | MPa | Optimal conditions (810 °C, 60 min, 10 MPa, 10 ”m Cr) |
| Optimal Bonding Temperature | 810 | °C | Highest tested temperature, promoted Cr3C2 formation |
| Optimal Holding Time | 60 | min | Time for complete defect closure and diffusion |
| Optimal Bonding Pressure | 10 | MPa | Pressure balancing defect closure and diamond integrity |
| Optimal Cr Interlayer Thickness | 10 | ”m | Thickness yielding highest strength and defect reduction |
| Diamond Metallization Layer | 100 | nm | Tungsten (W) layer applied to diamond surface |
| Interfacial Carbide Phase | Cr3C2, WC | N/A | Confirmed via XRD analysis at 810 °C |
| SPS Heating Rate | 20 | °C/min | Standard rate used during the diffusion bonding process |
Key Methodologies
Section titled âKey MethodologiesâThe SPS diffusion bonding process was optimized by systematically varying four key parameters: interlayer thickness, bonding temperature, holding time, and bonding pressure.
- Base Material Preparation:
- Diamond/Cu billets (60 vol% diamond) were fabricated using the vacuum pressure infiltration method.
- Diamond particles were pre-metallized with a 100 nm Tungsten (W) layer via magnetron sputtering to enhance initial wetting.
- Interlayer Selection:
- High-purity Chromium (Cr) foil (99.99%) was used as the interlayer material.
- Cr thickness was varied across 10 ”m, 30 ”m, and 50 ”m to study diffusion kinetics and defect formation.
- SPS Diffusion Bonding:
- The stacked materials (Diamond/Cu | Cr | Diamond/Cu) were placed in a graphite mold.
- Heating Rate was fixed at 20 °C/min, and the pulse duty cycle was set to 10 ms:10 ms.
- Parameter Ranges Tested (Table 1):
- Temperature: 720 °C to 810 °C.
- Holding Time: 30 min to 90 min.
- Pressure: 7.5 MPa to 12.5 MPa.
- Interfacial Analysis:
- Scanning Electron Microscopy (SEM) and Energy-Dispersive Spectroscopy (EDS) were used to observe microstructure and element distribution across the three characteristic layers (Cu matrix, diffusion layer, undiffused interlayer).
- X-ray Diffraction (XRD) confirmed the formation of key interfacial phases, specifically Cr3C2, which is crucial for chemical bonding.
- Property Measurement:
- Shear strength was tested at room temperature to evaluate mechanical integrity.
- Thermal diffusion coefficient was measured using the laser flash method (LFA 467HT), and Thermal Conductivity (TC) was calculated using the formula: λ = αÏC.
Commercial Applications
Section titled âCommercial ApplicationsâThe successful SPS diffusion bonding of high-TC diamond/Cu composites with enhanced mechanical strength is directly applicable to industries requiring robust thermal management solutions for high heat flux environments.
- Advanced Microelectronics: Manufacturing high-performance heat sinks and thermal spreaders for CPUs, GPUs, and integrated circuits, addressing the dramatic rise in heat flow density in miniaturized chips.
- High-Power Devices (HPD): Creating reliable, low-residual-stress joints for components in power modules (e.g., IGBTs, MOSFETs) used in electric vehicles, renewable energy systems, and industrial controls.
- Aerospace and Defense Systems: Fabrication of lightweight, high-strength thermal management components for radar systems, avionics, and satellite electronics where thermal stability and mechanical reliability are paramount.
- Complex Component Manufacturing: Utilizing the SPS diffusion bonding technique to produce diamond/Cu components with complex geometries that are inaccessible via traditional powder metallurgy or high-temperature brazing.
- Interface Engineering: The methodology of using active metal interlayers (Cr) to promote carbide formation (Cr3C2) can be applied to improve bonding and reduce acoustic mismatch in other metal-ceramic composite systems.
View Original Abstract
Spark plasma sintering (SPS) is an effective technique for studying the diffusion bonding of diamond/Cu composites, and has the potential to advance the application of copper matrix composites. This study investigates the SPS diffusion bonding of diamond/Cu composites using a chromium (Cr) interlayer. The effects of process parameters on the microstructure and mechanical properties of the bonding interface were evaluated through shear strength testing and SEM analysis. The results show that shear strength increases with interlayer thickness up to a certain point, after which it decreases. As the bonding temperature, holding time, and bonding pressure increase, defects such as cracks and voids at the diffusion-bonded interface are reduced, resulting in improved shear strength. Under suitable conditions (10 Όm interlayer, 810 °C, 60 min, and 10 MPa), the bonding interface is defect-free, achieving a maximum shear strength of 139.89 MPa and a thermal conductivity (TC) of 700.97 W/(m·K), indicating high-quality diffusion bonding.
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 2020 - Progress in heat conduction of diamond/Cu composites with high thermal conductivity
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