The Influence of the Carbide-Forming Metallic Additives (W, Mo, Cr, Ti) on the Microstructure and Thermal Conductivity of Copper–Diamond Composites
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2023-05-26 |
| Journal | Journal of Composites Science |
| Authors | Arina V. Ukhina, Dina V. Dudina, Maksim A. Esikov, Д. А. Самошкин, С. В. Станкус |
| Institutions | Institute of Solid State Chemistry and Mechanochemistry, Lavrentyev Institute of Hydrodynamics |
| Citations | 7 |
| Analysis | Full AI Review Included |
Technical Analysis: Copper-Diamond Composites for High-Performance Heat Sinks
Section titled “Technical Analysis: Copper-Diamond Composites for High-Performance Heat Sinks”This document analyzes the research on carbide-forming metallic additives in copper-diamond composites, focusing on the implications for advanced thermal management applications. The findings are directly correlated with the material science and customization capabilities offered by 6CCVD.
Executive Summary
Section titled “Executive Summary”- Application Focus: The study addresses the critical need for high-efficiency heat sink materials in microelectronics, targeting improved thermal conductivity (TC) in copper-diamond (Cu-D) composites.
- Interfacial Optimization: Carbide-forming metallic additives (W, Mo, Cr, Ti) were introduced into the copper matrix to enhance the wettability of diamond particles and minimize interfacial thermal resistance.
- Optimal Additive: Titanium (Ti) proved the most effective additive, achieving the highest thermal conductivity due to its high solubility in copper and the resulting formation of highly stable Titanium Carbide (TiC) at the diamond interface.
- Peak Performance: The maximum thermal conductivity achieved was 420 W m-1 K-1 using 0.7 vol.% Ti additive consolidated via Spark Plasma Sintering (SPS).
- Methodology Impact: SPS was demonstrated to be superior to Hot Pressing (HP) for Ti-modified composites, likely due to the influence of electric current promoting faster Ti diffusion and more uniform wetting.
- Thermodynamics: Gibbs free energy calculations confirmed that TiC formation ($\Delta$G° = -87 kJ) is the most thermodynamically favored carbidization reaction among the studied additives (W, Mo, Cr) at the sintering temperature (920 °C).
Technical Specifications
Section titled “Technical Specifications”The following hard data points were extracted from the experimental results, focusing on optimal performance parameters.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Thermal Conductivity ($\lambda$) | 420 ± 21 | W m-1 K-1 | 0.7 vol.% Ti additive, SPS method |
| Sintering Temperature | 920 | °C | Used for both SPS and HP methods |
| Consolidation Pressure | 40 | MPa | Uniaxial pressure applied |
| Optimal Ti Concentration | 0.7 | vol.% | Yielded highest TC via SPS (Sample 9) |
| Diamond Concentration | 50 | vol.% | Constant across all composite samples |
| Diamond Particle Size (Raw) | 100 | µm | Synthetic diamond (MBD10) |
| Sintering Atmosphere (SPS) | 10 | Pa | Forevacuum residual pressure |
| Sintering Atmosphere (HP) | 0.1 | MPa | Argon atmosphere |
| Most Stable Carbide ($\Delta$G°) | -87 | kJ | TiC formation at 920 °C |
| Maximum Cu Lattice Parameter | 3.623 ± 0.002 | Å | Observed in 2 vol.% Ti, HP sample (indicates Ti incorporation) |
Key Methodologies
Section titled “Key Methodologies”The study utilized advanced powder metallurgy techniques to synthesize and characterize the copper-diamond composites.
- Raw Material Preparation: Powders of synthetic diamond (100 µm) and copper (40 µm) were mixed with carbide-forming additives (Ti, Cr, Mo, W).
- Composition Control: Diamond concentration was fixed at 50 vol.%. Additive concentrations were varied between 0.15 vol.% and 2 vol.%.
- Sintering Methods: Two primary consolidation techniques were employed:
- Spark Plasma Sintering (SPS): Conducted on a Labox 1575 facility at 920 °C with holding times of 3 min and 10 min, under forevacuum conditions (10 Pa).
- Hot Pressing (HP): Conducted on a custom-built setup at 920 °C with a 15 min holding time, under an Argon atmosphere (0.1 MPa).
- Pressure Application: A consistent uniaxial pressure of 40 MPa was applied during both SPS and HP consolidation.
- Microstructural Analysis: Scanning Electron Microscopy (SEM) was used to examine the fracture surfaces and the quality of the copper-diamond interface, confirming improved wetting with Ti.
- Phase Analysis: X-ray Diffraction (XRD) was used to determine phase composition. Detailed analysis confirmed the presence of copper and diamond peaks, and suggested the formation of small crystallites of Titanium Carbide (TiCx) in the high-Ti concentration samples.
- Thermal Measurement: Thermal diffusivity ($\alpha$) was measured using the Laser Flash Method (LFA-427), and thermal conductivity ($\lambda$) was calculated using the formula: $\lambda = \alpha \rho C_{p}$.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The research highlights that achieving high thermal conductivity in metal-diamond composites hinges on precise interfacial engineering and material purity. 6CCVD provides the foundational diamond materials and customization services necessary to replicate or significantly advance this research for commercial heat sink applications.
| Research Requirement/Challenge | 6CCVD Solution & Capability | Technical Advantage |
|---|---|---|
| High-Purity Diamond Substrate | Optical Grade SCD or High Purity PCD | While the paper used powder, high-end heat sinks require large, robust substrates. Our SCD offers TC > 2000 W m-1 K-1. Our PCD plates are available up to 125mm diameter. |
| Interfacial Bonding Layer (TiC) | Custom Metalization Services (Ti, W, Cr, Cu) | We offer internal deposition capabilities for carbide-forming metals (Ti, W) directly onto diamond surfaces. This allows researchers to utilize the “preliminary modification” approach (forming thin coatings) for highly controlled, uniform carbide layers, potentially surpassing the 420 W m-1 K-1 achieved by in situ alloying. |
| Precise Substrate Dimensions | Custom Dimensions and Polishing | We supply SCD and PCD wafers with thicknesses ranging from 0.1 µm to 500 µm (up to 10 mm for substrates). Our polishing achieves surface roughness of Ra < 1nm (SCD) and Ra < 5nm (Inch-size PCD), critical for minimizing thermal boundary resistance (TBR) in subsequent bonding steps. |
| Scaling and Manufacturing | Large-Area PCD Wafers (up to 125mm) | Our ability to produce large-format PCD allows for the direct fabrication of high-performance heat spreaders and thermal management components required by modern microelectronics and high-power devices. |
| Advanced Material Integration | Engineering Support for Thermal Projects | 6CCVD’s in-house PhD team specializes in material selection and surface preparation for high-TC applications. We can assist engineers in selecting the optimal diamond material (SCD vs. PCD) and metalization stack (e.g., Ti/Pt/Au) for integration into SPS or HP processes. |
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We offer global shipping (DDU default, DDP available) to support your most demanding research and development projects.
View Original Abstract
In this study, carbide-forming metallic additives (W, Mo, Cr, Ti) were introduced into the copper matrix to improve the wettability of diamond particles in the copper-diamond composites. The samples were prepared by Spark Plasma Sintering (SPS) and Hot Pressing (HP) at 920 °C. The phase composition, microstructure and thermal conductivity of the samples were investigated. The influence of the carbide-forming additive concentration, the sintering method as well as the nature of the metal introduced into the copper matrix on the thermal conductivity of copper-diamond composites was determined. Titanium ensured a more significant wettability improvement at the copper-diamond interface. This is due to its higher solubility in copper in comparison with other metals (W, Mo, Cr) and the possibility of its diffusion through the copper matrix to the diamond surface resulting in the formation of a closer contact at the copper-diamond interface.
Tech Support
Section titled “Tech Support”Original Source
Section titled “Original Source”References
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