Fabrication of high thermal conductivity copper/diamond composites by electrodeposition under potentiostatic conditions
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-03-09 |
| Journal | Journal of Applied Electrochemistry |
| Authors | Susumu Arai, Miyoka Ueda |
| Institutions | Shinshu University |
| Citations | 19 |
| Analysis | Full AI Review Included |
Technical Documentation and Analysis: High Thermal Conductivity Cu/Diamond Composites
Section titled âTechnical Documentation and Analysis: High Thermal Conductivity Cu/Diamond CompositesâThis documentation analyzes the research concerning the fabrication of high thermal conductivity copper/diamond composites via potentiostatic electrodeposition, positioning 6CCVD materials as the enabling component for scaling and optimizing this technology for advanced thermal management applications.
Executive Summary
Section titled âExecutive SummaryâThe research successfully demonstrated a novel, low-temperature, and low-pressure method for fabricating ultra-high thermal conductivity Cu/Diamond composites, overcoming the limitations of traditional sintering and infiltration techniques.
- Superior Thermal Performance: Composites achieved a peak thermal conductivity of 600 W m-1 K-1, representing a 1.5x improvement over pure copper (ca. 400 W m-1 K-1).
- Methodological Breakthrough: Potentiostatic electrodeposition was utilized successfully at a carefully controlled potential (-0.20 V vs. SCE) to completely suppress undesired hydrogen gas (H2) evolution.
- Dense Morphology Achieved: Suppression of H2 evolution resulted in highly compact composite structures with excellent interfacial contact, eliminating the gaps/cracks common in high-temperature fabrication.
- Component Requirement: The key starting material was high-quality, single-crystal diamond particles, confirming diamondâs role as the superior filler material for isotropic thermal management.
- Scalability Potential: Electrodeposition techniques are highly scalable, suggesting a viable route for large-area heat sink fabrication using high-purity 6CCVD Polycrystalline Diamond (PCD) substrates.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted, detailing the material performance and critical fabrication parameters achieved under potentiostatic conditions.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Thermal Conductivity ($\lambda$) | 600 | W m-1 K-1 | Composite (49 vol% D, 230 ”m mean size) |
| Thermal Conductivity Enhancement | 1.5 | Ratio | Relative to pure Copper ($\lambda$ ca. 400 W m-1 K-1) |
| Diamond Particle Size Range Used | 10-230 | ”m | Mean diameter of single-crystal diamond |
| Density of Diamond ($\rho$dia) | 3.52 | g dm-3 | Used for theoretical calculation |
| Density of Copper ($\rho$Cu) | 8.94 | g dm-3 | Used for theoretical calculation |
| Critical Deposition Potential | -0.20 | V | vs. SCE (0.0412 V vs. SHE) |
| Galvanostatic Current Density Issue | 4-10 | Times Higher | Current density on D-particle layer vs. plain Cu, causing H2 evolution |
| Assumed Boundary Conductance ($h$c) | 8.86 x 108 | W m-2 K-1 | Used in Hasselman-Johnson simulation |
Key Methodologies
Section titled âKey MethodologiesâThe successful fabrication hinged on precise control of the electrochemical environment to ensure homogeneous deposition and optimal particle packing.
- Electrode Configuration: Electrodes were arranged horizontally, with the cathode positioned at the bottom of the plating bath to facilitate particle precipitation.
- Diamond Particle Precipitation: Commercially available single-crystal diamond particles (10, 25, 45, and 230 ”m) were dispersed, allowed to settle, and precipitated onto the cathode substrate (typically forming a bilayer).
- Electrolyte: An aqueous solution consisting of 0.85 M CuSO4·5H2O and 0.55 M H2SO4 was used as the copper plating bath.
- Galvanostatic Failure Analysis: Initial tests showed that under constant current (galvanostatic) conditions, current densities became too high (4-10x typical), leading to rapid, turbulent hydrogen gas evolution and subsequent disruption of the particle arrangement.
- Potentiostatic Success: Copper was electrodeposited under highly controlled potentiostatic conditions at -0.20 V vs. SCE (or 0.0412 V vs. SHE). This potential ensures copper deposition while operating below the threshold required for hydrogen evolution, resulting in compact, gap-free composites.
- Characterization: Thermal diffusivity ($\alpha$) was measured using a xenon laser flash system, and thermal conductivity ($\lambda$comp) was calculated using the formula: $\lambda$comp = $\alpha$ · $\rho$comp · $C$comp.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThis research validates diamond as the prime material for high-performance heat sinks. 6CCVD offers the specialized diamond substrates and customization necessary to replicate this research and scale it for industrial applications, ensuring maximum thermal efficiency and structural integrity.
Applicable Materials for Replication and Extension
Section titled âApplicable Materials for Replication and ExtensionâTo replicate the high-purity results achieved in this study, researchers should utilize 6CCVDâs premium material selection:
- Optical Grade SCD (Single Crystal Diamond): Recommended for achieving the highest purity and structural uniformity necessary for manufacturing the base diamond particles or high-performance SCD substrates.
- Electronic/Thermal Grade PCD (Polycrystalline Diamond): Ideal for use as the cathode substrate, especially when scaling the process. 6CCVD provides PCD plates up to 125mm in diameter, suitable for large-scale heat spreader or module fabrication.
Customization Potential & Technical Advantage
Section titled âCustomization Potential & Technical Advantageâ6CCVDâs comprehensive capabilities are uniquely suited to optimize the fabrication technique described in this paper, particularly regarding interface quality and scale-up:
| Research Requirement | 6CCVD Capability & Solution | Thermal/Sales Advantage |
|---|---|---|
| Particle Pre-Coating (Interface Enhancement) | Custom Metalization Services: We offer in-house deposition of Au, Pt, Pd, Ti, W, and Cu. | Pre-coating diamond particles with a thin layer of Ti or W prior to electrodeposition can further enhance the $\lambda$comp by reducing the interfacial thermal resistance ($h$c) between the copper matrix and the diamond. |
| Large-Area Substrates | PCD Wafers up to 125mm: Custom dimensions and thicknesses (0.1”m - 500”m PCD film, Substrates up to 10mm). | Allows for immediate scaling of composite fabrication into industrial-sized heat spreaders or complex thermal pathways required in electronics cooling. |
| Surface Finish Requirements | Precision Polishing: Achievable SCD surface roughness of Ra < 1nm, and Inch-size PCD Ra < 5nm. | Provides ultra-smooth cathode surfaces, ensuring optimal, uniform adhesion of the initial diamond particle layer and improving the structural integrity of the resulting composite interface. |
| Substrate Doping | Boron-Doped Diamond (BDD): We offer tailored BDD material. | If the substrate itself needs enhanced electrical conductivity for uniform current density control during electrodeposition, BDD substrates can be utilized as high-performance, conductive cathodes. |
Engineering Support
Section titled âEngineering SupportâThis study highlights the need for precise electrochemical control when integrating diamond into metal matrices. 6CCVDâs in-house team of PhD material scientists specializes in CVD growth and surface chemistry. We offer technical consultancy for projects in Advanced Thermal Management, High Power Electronics Cooling, and Composite Material Development. Our team can assist in selecting the optimal diamond type (SCD vs. PCD), specifying interfacial coatings, and optimizing material parameters for successful large-scale electrodeposition.
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We ship globally (DDU default, DDP available).
View Original Abstract
Abstract High thermal conductivity Cu/diamond composites were fabricated using an electrodeposition technique. The electrodes were oriented horizontally, and the cathode was located at the bottom of the plating bath. Diamond particles (10-230 ÎŒm) were first precipitated on the cathode substrate, and then copper was electrodeposited on the substrate to fill the gap between the precipitated diamond particles, which resulted in the formation of a Cu/diamond composite. The deposition behavior of the copper was electrochemically investigated, and the current densities of copper deposition under galvanostatic conditions were estimated. The current densities for the substrate with diamond particle layers were 4-10 times higher than the current density for the substrate without diamond particle layers, which led to undesired hydrogen evolution. Cu/diamond composites were formed under potentiostatic conditions without hydrogen evolution, and the resultant composites had compact morphologies. A specimen containing 49 vol% diamond particles with a mean diameter of 230 ÎŒm had the highest thermal conductivity of 600 W m â1 K â1 , which is 1.5 times that of pure copper (ca. 400 W m â1 K â1 ). Graphic Abstract High thermal conductivity Cu/diamond composites were fabricated by electrodeposition under a potentiostatic condition without the evolution of hydrogen gas.