Processing of Single Crystal Diamond (1 0 0) Plane Using Wear with Ferrous Disk

At a Glance

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

Technical Documentation: Single Crystal Diamond Processing via Thermal-Chemical Wear

This document analyzes the research on processing Single Crystal Diamond (SCD) (100) surfaces using controlled wear against ferrous disks, focusing on the thermal-chemical reaction mechanism. The findings are leveraged to demonstrate 6CCVD’s capabilities in supplying high-specification MPCVD diamond materials for advanced manufacturing and research applications.

Executive Summary

This research successfully demonstrated a novel, non-mechanical method for shaping Single Crystal Diamond (SCD) by utilizing controlled thermal-chemical wear against a ferrous disk (SK85 steel).

Core Mechanism: Diamond processing is achieved by inducing localized graphitization through high temperature (> 700 °C) and high pressure friction, followed by the removal of the graphitized layer by the ferrous wear debris.
Material Integrity: Raman spectroscopy confirmed that despite reaching graphitization temperatures, the processed SCD surface and bulk material remained pristine, showing no residual graphite or amorphous carbon.
Shape Transfer: The method successfully transferred the shape of the ferrous disk (grooving) onto the SCD (100) surface, demonstrating potential for complex 3D shaping.
Process Optimization: The use of a correction apparatus to remove peripheral burrs on the ferrous disk was critical for achieving a precise, rectangular groove shape on the diamond.
Material Dependence: Ferrous materials (SK85) yielded significantly higher processing volumes compared to non-ferrous materials (C2801 brass), confirming the necessity of the thermal-chemical reaction involving carbon diffusion into the iron.
6CCVD Value Proposition: 6CCVD provides the high-purity, precisely oriented SCD (100) plates required for replicating and advancing this high-temperature processing technique.

Technical Specifications

The following hard data points were extracted from the experimental results regarding material properties and optimized processing conditions.

Parameter	Value	Unit	Context
Diamond Material	Single Crystal Diamond (SCD)	N/A	(100) orientation
Diamond Plate Dimensions	2.8 x 2.5 x 1.2	mm	Plate size and height
Ferrous Disk Material	SK85 Steel	N/A	Carbon content: 0.83%
Non-Ferrous Disk Material	C2801 Brass	N/A	Carbon content: 0%
Ferrous Disk Hardness	180	HV	Vickers Hardness
Non-Ferrous Disk Hardness	119	HV	Vickers Hardness
Optimal Circumferential Speed	500	m/min	Used for maximum processing volume
Optimal Feed Rate	1.0	µm/s	Standard feed rate
Processing Temperature Reached	> 700	°C	Measured at diamond/holder interface (indicates graphitization threshold reached)
Raman Peak Confirmation	1332	cm^-1	Confirms pure diamond structure (no graphite shift near 1600 cm^-1)
Maximum Processed Volume (SK85)	~0.25	mm³	Achieved at 500 m/min, 40 min
Disk Thickness	0.3	mm	Used for localized wear

Key Methodologies

The experiment utilized a specialized MPCVD SCD plate and a rotating ferrous disk to induce controlled thermal-chemical wear.

Material Preparation: Single Crystal Diamond (100) plates (2.8 x 2.5 x 1.2 mm) were secured in a holder. Thin ferrous (SK85) or non-ferrous (C2801) disks (0.3 mm thickness) were prepared.
Thermal Isolation: Paper was inserted between the diamond and the holder to act as a heat insulator, preventing heat dissipation and promoting the rapid temperature rise necessary for graphitization at the contact interface.
Processing Setup: The diamond was pressed against the circumference of the rotating disk, ensuring localized contact only on the diamond’s (100) face.
Burr Correction: A specialized correction apparatus (using two grinding wheels) was implemented in situ to continuously remove burrs forming on the outer edge of the rotating disk, which was critical for maintaining a precise, rectangular groove shape transfer.
Parameter Variation: Experiments varied circumferential speed (250-500 m/min), feed rate (0.5-1.5 µm/s), and processing time (up to 40 min) to optimize material removal volume.
Temperature Measurement: A K-type thermocouple (100 µm diameter) was placed between the diamond and the holder to monitor the temperature, confirming that the graphitization threshold (> 700 °C) was reached during processing with SK85.
Post-Processing Analysis: Processed groove shapes were measured using optical microscopy and stylus profilometry. Raman spectroscopy (532 nm laser, 2 µm spot size) was used to analyze the surface and depth profile of the diamond to confirm the absence of residual graphite or amorphous carbon.

6CCVD Solutions & Capabilities

This research highlights the critical need for high-quality, precisely oriented SCD material capable of withstanding extreme thermal and mechanical stress. 6CCVD is uniquely positioned to supply the materials and customization required to replicate and advance this thermal-chemical processing technology.

Applicable Materials & Requirements	6CCVD Solution & Capability	Technical Advantage for Research
High-Purity SCD (100) Plates	Optical Grade Single Crystal Diamond (SCD)	We supply high-purity SCD wafers up to 500 µm thick, ensuring consistent crystal orientation (100) and minimal defects, crucial for reproducible thermal-chemical reactions.
Custom Dimensions & Geometry	Precision Laser Cutting and Sizing	The paper used small, custom-sized plates (2.8 x 2.5 mm). 6CCVD offers custom dimensions up to 125 mm (PCD) and precise laser cutting services to meet exact experimental holder specifications.
Surface Quality	Ultra-Low Roughness Polishing	We provide SCD with surface roughness (Ra) < 1 nm. A superior starting surface ensures that the wear mechanism is controlled solely by the thermal-chemical reaction, not pre-existing mechanical defects.
Advanced Material Exploration	Boron-Doped Diamond (BDD) & PCD	To extend this research (e.g., exploring electrical assistance or scaling), 6CCVD offers heavy Boron-Doped Diamond (BDD) for conductive experiments, and large-area Polycrystalline Diamond (PCD) plates.
Thermal Management Integration	Custom Substrates and Metalization	We can supply robust diamond substrates up to 10 mm thick. If future work requires integrated heating elements or thermal sensors, 6CCVD offers in-house metalization services (Au, Pt, Ti, W, etc.) for direct integration onto the diamond surface.

Engineering Support

6CCVD’s in-house PhD team specializes in MPCVD growth and diamond material science. We can assist researchers and engineers with material selection, orientation specification, and thermal modeling for similar high-temperature diamond processing projects, ensuring optimal material performance under extreme conditions.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

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.

Tech Support

Original Source

DOI: https://doi.org/10.2493/jjspe.90.132