THE MAGNETIC PROPERTIES OF DIAMOND COMPOSITES WITH THE ADDITION OF GRAPHENE
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2023-04-30 |
| Journal | Sworld-Ger conference proceedings |
| Authors | А. Н. Соколов, Vladyslav Harhin, Nataliia Rusinova |
| Institutions | V. Bakul Institute for Superhard Materials |
| Analysis | Full AI Review Included |
The Magnetic Properties of Diamond Composites with the Addition of Graphene
Section titled “The Magnetic Properties of Diamond Composites with the Addition of Graphene”Executive Summary
Section titled “Executive Summary”This research investigates the synthesis and magnetic characterization of diamond polycrystalline composites fabricated using High-Pressure/High-Temperature (HPHT) sintering with n-layer graphene additives.
- Ferromagnetic Achievement: The resulting diamond composites exhibit robust ferromagnetic properties, confirmed by the presence of a distinct hysteresis loop in all tested samples.
- Material Classification: Based on the measured coercive force (Hc), the materials are classified as magnetically solid, comparable to commercial permanent magnet alloys (e.g., vikalla, kunife, Fe-Co-Cr).
- Additive Role: The addition of n-layer graphene nanoplates (Gn(4)) acts as an activating additive, influencing the electromagnetic properties of the diamond polycrystal.
- Process Optimization: Reducing the diamond powder grain size (from 40/28 µm to 14/10 µm) had the most significant effect, increasing the coercive force by 1.4-1.6 times and simultaneously reducing magnetic losses (hysteresis loop area) by 2.5-2.7 times.
- Mechanism Hypothesis: Ferromagnetism is attributed to either ferromagnetic impurities in the diamond powders (natural or synthetic) or spontaneous magnetic ordering within the nanographene layers caused by lattice distortions.
- Future Scope: The development expands the application of diamond composites into creating permanent magnets and potentially unique, biocompatible magnets for medical and biological uses.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Sintering Pressure | 7.0 - 7.5 | GPa | HPHT process using “toroid” HPD |
| Sintering Temperature | 1250 - 1350 | °C | Sintering duration approximately 200 s |
| Sintering Duration | ~200 | s | Time at peak temperature/pressure |
| Synthetic Diamond Grain Size (DSM) | 40/28 | µm | Used with 0.5% and 1.0% Gn(4) |
| Natural Diamond Grain Size (DM) | 14/10 | µm | Used with 0.3% Gn(4) |
| Graphene Nanoplate Thickness | Less than 3 | nm | Gn(4) brand, less than four layers |
| Magnetic Saturation Field (Hms) | 5000 | E (Oersted) | Field strength required for magnetic saturation |
| Max Coercive Force (Hc) | 303.22 | e (Oersted) | Achieved with DM 10/14 + 0.3% Gn(4) |
| Max Magnetic Saturation (ms) | 75.435 x 10-3 | emo/g | Achieved with DSM 40/28 + 1.0% Gn(4) |
| Magnetometer Sensitivity | 10-7 | emo | Vibrating Magnetometer 7404 VSM |
| Microweights Sensitivity | 10-5 | g | Mettler Toledo AB135-S / FACT |
Key Methodologies
Section titled “Key Methodologies”The diamond-graphene composites were synthesized and characterized using the following high-density process parameters:
- Raw Materials: Micro-powders of synthetic diamond (DSM 40/28) and natural diamond (DM 14/10) were mixed with Graphene Gn(4) nanoplates. Graphene concentrations ranged from 0.3% to 1.0% by weight.
- Graphene Selection: Gn(4) was chosen because it resists phase transformation into diamond under the applied HPHT conditions, ensuring the secondary phase remains graphene.
- Sintering Equipment: A DO-043 press unit, capable of developing 20 MN of force, was utilized. Sintering was performed within a “toroid” type High-Pressure Device (HPD) with a 30 mm central recess.
- HPHT Sintering Cycle: The charge was subjected to a pressure of 7.0-7.5 GPa and a temperature range of 1250-1350 °C. The sintering duration was held constant at approximately 200 seconds.
- Sample Preparation: Post-sintering, the composite samples (4 mm diameter, 4.5 mm height) were chemically treated to remove any residual graphite from the surface.
- Magnetic Measurement: Magnetic characteristics were analyzed using a Vibrating Sample Magnetometer (VSM 7404) in magnetic fields up to 13 kE to accurately measure the magnetic moment and plot the hysteresis loop.
Commercial Applications
Section titled “Commercial Applications”The development of ferromagnetic diamond composites opens avenues in specialized fields requiring materials that combine extreme mechanical properties with tailored magnetic response.
| Application Area | Specific Product/Function | Key Material Advantage |
|---|---|---|
| Permanent Magnet Manufacturing | Micro-magnets, high-stability magnetic components, magnetic seals. | High coercive force (up to 303 e) combined with diamond’s extreme hardness and thermal stability. |
| Biomedical Engineering | Biocompatible magnetic implants, targeted drug delivery systems, magnetic hyperthermia agents. | Diamond’s inherent biocompatibility coupled with induced magnetism, potentially offering unique non-toxic magnetic materials. |
| Advanced Tooling & Sensing | Diamond composite cutting tools with integrated magnetic sensing capabilities, electromagnetic shielding components. | High electrical conductivity (as noted in prior work [2]) and ferromagnetic properties integrated into a superhard matrix. |
| High-Pressure/High-Temperature Devices | Components requiring magnetic functionality that must operate reliably under extreme force and temperature fields. | Stability of the diamond matrix and the resistance of Gn(4) graphene to phase transformation under HPHT conditions. |
View Original Abstract
The paper presents the results of studying the magnetic properties by magnetometry using a vibrating magnetometer “Vibrating Magnetometer 7404 VSM” of diamond polycrystals obtained by sintering diamond powders with the addition of n-layer graphene at high