Heat-conducting properties of thermobarically-sintered detonation nanodiamond
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2022-12-01 |
| Journal | Letters on Materials |
| Authors | В. А. Плотников, Denis Bogdanov, Alexander Bogdanov, А. А. Чепуров, С. В. Макаров |
| Institutions | Altai State University, V.S. Sobolev Institute of Geology and Mineralogy |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled “Executive Summary”This research highlights the limitations of thermobarically-sintered Detonation Nanodiamond (DND) composites for high-performance thermal management, contrasting their low thermal conductivity ($\lambda$) with the superior performance of high-quality Single Crystal Diamond (SCD).
- Performance Gap: The maximum thermal conductivity observed in DND composites was extremely low, peaking at 19 W/(mK) at 50°C. This is two orders of magnitude lower than the 2089 W/(mK) achieved by high-quality SCD referenced in the study.
- Thermal Resistance Mechanism: The low $\lambda$ in DND is attributed to the predominance of phonon scattering at the boundaries of the 4.5 nm nanocrystals, rendering the material unsuitable for efficient heat sinks.
- Anomalous Behavior: DND composites exhibited anomalous, non-monotonic, and temperature-independent $\lambda$ in the 50-300°C range, confirming that boundary scattering dominates over classical phonon mechanisms.
- 6CCVD Solution: To meet the industry requirement of >400 W/(mK) for heat-removing materials, 6CCVD provides high-purity, large-grain MPCVD SCD and PCD engineered specifically to minimize internal defects and boundary scattering.
- Material Recommendation: Replication or extension of high-performance thermal applications requires Optical Grade SCD from 6CCVD, capable of achieving thermal conductivities well over 2000 W/(mK).
- Customization: 6CCVD offers custom dimensions (up to 125mm) and integrated metalization services necessary for direct integration into advanced thermal management devices.
Technical Specifications
Section titled “Technical Specifications”The following data points contrast the performance of the tested nanodiamond composites with high-quality diamond materials, emphasizing the need for high-purity SCD.
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Max $\lambda$ (DND Composite) | 19 | W/(mK) | Thermobarically sintered |
| Min $\lambda$ (DND Composite) | 7 | W/(mK) | Thermobarically sintered |
| $\lambda$ (High-Quality SCD Reference) | 2089 | W/(mK) | Fe-Al-C system, 50°C |
| $\lambda$ (Synthetic SCD Reference) | 606.7 | W/(mK) | Fe-Ni-C system, 50°C |
| $\lambda$ (Micron-sized Metal-Diamond Composite) | 485.6 | W/(mK) | Powder-based composite |
| Target $\lambda$ for Heat-Removing Materials | > 400 | W/(mK) | Industry requirement |
| Sintering Pressure | 5 | GPa | Thermobaric process (BARS) |
| Sintering Temperature Range | 1100 - 1500 | °C | Tested range for DND |
| Nanocrystal Size (DND) | 4.5 | nm | Determines phonon scattering limit |
| Measurement Temperature Range | 50 - 300 | °C | Thermal conductivity testing range |
Key Methodologies
Section titled “Key Methodologies”The research focused on thermobaric sintering of detonation nanodiamond (DND) powder to form composite materials, followed by thermal conductivity and Raman spectroscopy analysis.
- Starting Material: Detonation nanodiamond powder (DND) was used, pressed into 8 mm diameter disks.
- Sintering Apparatus: High-pressure multi-anvil “split-sphere” apparatus (BARS) was employed.
- Pressure Application: Sintering was executed under a constant pressure of 5 GPa.
- Temperature Variation: Five distinct sintering temperatures were tested: 1100, 1200, 1300, 1400, and 1500°C.
- Time and Quenching: Samples were held at temperature for 60 seconds, followed by rapid cooling (quenching time of 2-3 seconds).
- Encapsulation: Samples were placed in capsules fabricated from refractory MgO oxide.
- Thermal Measurement: Thermal conductivity ($\lambda$) was measured using a TM-X-400 apparatus in a monotonous heating mode across the 50-300°C range.
- Structural Analysis: Raman spectra were obtained using a LabRAM HR800 microspectrometer (325 nm and 532 nm excitation) to analyze non-diamond phases (Graphite G-line, Disordered Graphite D-line).
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The research confirms that nanostructured diamond composites are severely limited by boundary scattering, resulting in thermal conductivity values (7-19 W/(mK)) far below the threshold required for effective heat sinks (>400 W/(mK)). 6CCVD specializes in MPCVD diamond materials engineered to overcome these limitations through high purity and controlled crystal growth.
Applicable Materials for High-Performance Thermal Management
Section titled “Applicable Materials for High-Performance Thermal Management”To replicate or exceed the high thermal conductivity values (e.g., 2089 W/(mK)) cited in the paper, researchers and engineers require materials with minimal defects and large crystal sizes to reduce phonon scattering.
| 6CCVD Material Solution | Description & Application | Relevant Capability |
|---|---|---|
| Optical Grade SCD | High-purity, low-defect Single Crystal Diamond. Essential for applications requiring $\lambda$ > 2000 W/(mK), such as high-power laser optics and advanced thermal spreaders. | Minimizes internal phonon scattering (impurities/defects). |
| High-Quality PCD | Large-grain Polycrystalline Diamond plates. Suitable for applications requiring $\lambda$ > 1000 W/(mK) where large area is critical. | Maximizes grain size (up to 125mm) to minimize boundary scattering effects. |
| Custom Substrates | SCD or PCD substrates up to 10mm thick. Ideal for robust heat-sinking panels and high-load mechanical applications. | Provides necessary mechanical strength and thermal mass. |
Customization Potential for Research Replication and Extension
Section titled “Customization Potential for Research Replication and Extension”The paper utilized specific sample dimensions (8 mm diameter disks) and referenced metal-diamond composites. 6CCVD’s in-house capabilities directly support the precise requirements of advanced materials research:
- Custom Dimensions: We offer plates and wafers up to 125mm (PCD) and custom-cut SCD pieces. We can provide materials matching or exceeding the 8 mm diameter used in the study, or scale up to inch-size wafers for industrial prototyping.
- Thickness Control: 6CCVD provides precise thickness control for both SCD (0.1µm - 500µm) and PCD (0.1µm - 500µm), allowing fine-tuning of thermal properties for specific device integration.
- Integrated Metalization: For replicating or improving upon the performance of metal-diamond composites (485.6 W/(mK) reference), 6CCVD offers internal metalization services, including deposition of Au, Pt, Pd, Ti, W, and Cu, ensuring low thermal boundary resistance (TBR) at the interface.
- Surface Finish: We provide ultra-smooth polishing (Ra < 1nm for SCD; Ra < 5nm for inch-size PCD), critical for minimizing surface defects that can contribute to phonon scattering and poor interface quality.
Engineering Support
Section titled “Engineering Support”6CCVD’s in-house PhD team specializes in the physics of diamond growth and thermal transport. We can assist researchers and engineers in selecting the optimal diamond material (SCD vs. PCD, specific doping levels) to ensure high thermal conductivity and low thermal boundary resistance for similar High-Power Thermal Management projects. We offer consultation on how material purity and crystal orientation impact phonon scattering mechanisms.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The research was conducted to study the thermal conductivity of detonation nanodiamonds-based composites. Composite nanodiamond materials were obtained in the course of thermobaric sintering at the press-free high-pressure apparatus (BARS) under 5 GPa and at temperatures within the range of 1100 -1500°С. It was ascertained that unlike diamond monocrystals with their thermal conductivity reaching up to 2100 W / (mK), the thermal conductivity of a nanodiamond composite is considerably lower and does not go beyond 18 W / (mK). Specifically, the temperature dependence of the thermal conductivity coefficient of a nanodiamond composite is anomalous as compared to a similar dependence in diamond monocrystals. The thermal conductivity coefficient in diamond monocrystals grows in compliance with the rising temperature, whereas it shows practically no changes in a nanodiamond composite in the temperature range of 50 - 300°С. Such a temperature dependence of the thermal-conductivity coefficient is apparently related to the features of the phonon spectrum of diamond monocrystals. This feature is stipulated by the dependence of the phonon spectrum of nanocrystals on their size, represented by a set of phonon modes in the range of the wave vector 0 < q <1 / L, i.e., the size of a diamond nanocrystal of 4.5 nm is alleged to limit the excitation of harmonics during nanodiamond composite heating, as opposed to macroscopic crystals that demonstrate the excitation of higher-frequency phonon modes during temperature growing.