Processing of Single Crystal Diamond (1 0 0) Plane Using Wear with Ferrous Disk
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2024-01-04 |
| Journal | Journal of the Japan Society for Precision Engineering |
| Authors | Go KADO, Takeshi NAKAMOTO |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis research presents a novel, non-mechanical method for processing single-crystal diamond (SCD) (100) surfaces by utilizing controlled thermal chemical wear against a rotating ferrous disk.
- Core Achievement: Successful transfer of the ferrous diskâs circumferential shape, creating precise grooves on the SCD (100) face.
- Mechanism Validation: The processing relies on the thermal chemical reaction (graphitization and carbon diffusion into the ferrous metal), confirmed by measured temperatures exceeding 700 °C during operation.
- Material Efficiency: Ferrous disks (SK85 steel) demonstrated significantly higher processing volume compared to non-ferrous brass disks (C2801), validating the necessity of the iron-carbon reaction.
- Shape Fidelity: A critical burr correction apparatus was developed and implemented to continuously remove burrs forming on the ferrous disk, ensuring the resulting diamond groove maintained a near-rectangular profile.
- Surface Quality: Raman spectroscopy confirmed the high quality of the processed diamond surface and subsurface (up to 15 ”m depth), detecting only the diamond peak (1332 cm-1) and confirming the absence of residual graphite or amorphous carbon.
- Process Control: Processing volume was shown to be highly dependent on processing time and circumferential speed, indicating the thermal nature of the removal process.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Diamond Orientation | (100) | - | Single crystal plane processed |
| Diamond Dimensions | 2.8 x 2.5 | mm x mm | Plane size |
| Ferrous Disk Material | SK85 | - | High hardness steel (HV 180, 0.83% C) |
| Non-Ferrous Disk Material | C2801 | - | Brass (HV 119, 0% C) |
| Disk Thickness | 0.3 | mm | Determines groove width |
| Circumferential Speed (Tested Range) | 250 - 500 | m/min | Processing parameter |
| Feed Rate (Tested Range) | 0.5 - 1.5 | ”m/s | Processing parameter |
| Max Measured Temperature | ~700 | °C | Diamond/Holder interface (SK85 disk) |
| Graphitization Temperature | >600 | °C | Temperature at which graphitization begins |
| Diamond Raman Peak | 1332 | cm-1 | Confirmed on processed surface |
| Raman Laser Wavelength | 532 | nm | Used for surface analysis |
| Raman Depth Analysis | Up to 15 | ”m | Depth analyzed for carbon residue |
| Required Groove Shape Correction | Burr removal | - | Necessary for achieving rectangular profile |
Key Methodologies
Section titled âKey Methodologiesâ- Processing Setup: A single-crystal diamond (100) face was mounted in a holder, insulated from the holder using paper to minimize heat conduction and maximize the temperature rise at the contact interface.
- Wear Mechanism Application: A thin (0.3 mm) rotating ferrous disk (SK85) was pressed against the diamond surface and fed laterally at controlled rates (0.5 to 1.5 ”m/s) to induce localized high-temperature, high-pressure wear.
- Shape Transfer Verification: The disk was intentionally offset (under shift or upper shift) relative to the diamond center to confirm that the resulting groove profile on the diamond accurately reflected the shape and position of the diskâs circumference.
- Burr Management: A specialized correction apparatus, utilizing two grinding stones, was implemented to continuously remove burrs (ăăȘ) that formed on the outer edge of the ferrous disk during processing. This step was critical for maintaining a precise, near-rectangular groove shape.
- Thermal Measurement: A K-type thermocouple (100 ”m diameter) was placed between the diamond and the holder to monitor the temperature rise, confirming that the contact zone reached temperatures sufficient for diamond graphitization (>700 °C).
- Surface Integrity Analysis: Post-processing analysis was performed using Raman spectroscopy. Measurements were taken at the groove base, both on the surface and in depth (up to 15 ”m), to verify the absence of graphitized carbon (peak shift to 1600 cm-1) or amorphous carbon (broadening of the Raman band).
Commercial Applications
Section titled âCommercial ApplicationsâThis method offers a non-mechanical pathway for creating complex, high-fidelity shapes on diamond, addressing limitations in traditional grinding and polishing.
- Precision Diamond Tooling: Fabrication of complex geometries (e.g., micro-grooves, specific radii) on single-point diamond cutting tools, improving performance and lifetime in ultra-precision machining of non-ferrous metals.
- Micro-Optics and Photonics: Creation of structured surfaces, such as micro-lenses, Fresnel lenses, or diffraction gratings, directly onto diamond windows or substrates, leveraging diamondâs transparency and hardness.
- Diamond Heat Spreaders: Shaping and patterning of diamond heat sinks for high-power density electronic devices (e.g., 5G/6G RF components, power converters) to optimize thermal pathways and bonding interfaces.
- Microfluidics and Bio-MEMS: Etching precise, damage-free micro-channels and reservoirs into diamond substrates for chemically inert and robust microfluidic devices.
- Advanced Wear Parts: Manufacturing diamond components requiring specific surface textures or grooves for reduced friction or enhanced lubrication in extreme environments.
View Original Abstract
Diamond has the highest hardness of all materials, high thermal conductivity and excellent optical transparency. However, it is very difficult to process the shape of the diamond because of its high hardness. By the way, when a ferrous material is cut by a diamond, the diamond is worn in spite of the diamond is much harder than the ferrous material. This phenomenon is called as thermal chemical reaction and occurs when the diamond is contacted with the ferrous material under high temperature and high pressure. This thermal chemical reaction is thought that results from the graphitization of diamond, the rapid diffusion of carbon atoms into the ferrous metal and others. In this research work, the worn due to the thermal chemical reaction was utilized diamond processing. A single crystal diamond is worn with a thin ferrous disk. This processing method was using the reactions at the interface of the diamond and the ferrous material, so the shape of the ferrous material of the contact surface can be expected to be transferred to the diamond. As a result, the diamond was grooved by the ferrous disk. Temperature of diamond during processing was measured using a K-type thermocouple. The diamond had reached the graphitization temperature. Raman spectroscopy was used to confirm if there is graphite on the diamond. Graphite was not detected on the diamond surface after processing, and only diamond peaks were detected.