Characterisation of single-crystal diamond grit for construction applications
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2015-11-20 |
| Authors | Stuart Nailer, T. Klein, M. MĂŒller, S. Grasberger |
| Institutions | Hilti (Liechtenstein) |
| Citations | 1 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Characterization of Single-Crystal Diamond for Engineered Applications
Section titled âTechnical Documentation & Analysis: Characterization of Single-Crystal Diamond for Engineered ApplicationsâThis document analyzes the findings regarding the characterization of single-crystal diamond (SCD) grit for construction applications and connects these requirements directly to the advanced capabilities and superior material quality offered by 6CCVDâs Microwave Plasma Chemical Vapor Deposition (MPCVD) diamond products.
Executive Summary
Section titled âExecutive Summaryâ- The research confirms that diamond tool performance (speed and lifetime) is critically dependent on precise material characterization, specifically focusing on particle strength, shape, and purity.
- Particle strength, measured via friability (toughness index) and compressive force, is statistically proven to be primarily influenced by a combination of high particle compactness (circularity) and low metallic inclusion content.
- Metallic inclusions, quantified via magnetic susceptibility (Ïv), act as weak points, severely reducing diamond strength and thermal stability, even when particle shape is optimal.
- Advanced statistical methods, including non-parametric percentiles and Weibull distributions, are necessary to accurately model the inherent variability (distributions) of particle size and strength in commercial grit products.
- The findings underscore the necessity of using ultra-high purity diamond materials, such as those produced by 6CCVDâs MPCVD process, which inherently eliminates the metallic catalyst inclusions found in traditional HPHT synthetic grit.
- 6CCVD provides engineered SCD and PCD materials with superior purity, controlled geometry, and custom metalization, enabling engineers to maximize the performance benefits of arranged-diamond segment technologies.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the characterization study, highlighting the metrics critical for high-performance diamond material selection:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Standard Grit Size Band | 30/35 US Mesh | N/A | Corresponds to 505”m to 645”m aperture size. |
| Particle Size Range (ECD) | 350 to 750 | ”m | Equivalent Circle Diameter (ECD) distribution for 30/40 full size. |
| PPC Variability (Blend Ratio) | Up to 18 | % | Difference in Particles Per Carat (PPC) between 60:40 and 40:60 blends. |
| Ideal Particle Shape Metric | Near 1 | N/A | Compactness value for highly crystalline, cubo-octahedral diamond. |
| Standard Friability Test Cycles | 1000 | Cycles | Used to determine single-value Toughness Index (TI). |
| Compressive Strength (Grade 1 Median) | Approx. 550 | N | Median fracture force for the strongest grade (30/35). |
| Compressive Strength (Grade 4 Median) | Approx. 350 | N | Median fracture force for the weakest grade (30/35). |
| Magnetic Susceptibility (Grade 1) | 21 | x 10-6 CGS | Lowest metallic inclusion content (highest strength). |
| Magnetic Susceptibility (Grade 4) | 123 | x 10-6 CGS | Highest metallic inclusion content (lowest strength). |
| High Toughness Index (TI) | > 84 | % residue | Achieved with low magnetic susceptibility and low median compactness. |
Key Methodologies
Section titled âKey MethodologiesâThe characterization of single-crystal diamond grit relies on a combination of physical separation, optical measurement, and mechanical testing to quantify material distributions rather than simple bulk averages.
- Particle Size Characterization:
- Sieving: Physical separation using internationally standardized US mesh sieves to define size bands (e.g., 30/35 half size).
- Particles Per Carat (PPC): Manual counting and weighing to determine the number of particles per unit mass (0.2g), critical for segment mass translation.
- Image Analysis for Size and Shape:
- Equivalent Circle Diameter (ECD): Calculated from the projected area of the particle using computerized optical microscopy, providing high-resolution size distribution data.
- Compactness: Defined as the ratio of the actual perimeter to the perimeter of a circle with the same projected area, used to quantify particle shape (circularity).
- Particle Strength Testing:
- Friability (Toughness) Testing: Measures resistance to cyclical impacts (e.g., 1000 cycles) in a steel capsule, yielding a percentage residue (Toughness Index, TI). Full residue-time curves are fitted using the Rosin-Rammler equation.
- Compressive Strength Testing: Measures the force (N) required to crush individual particles between two polycrystalline diamond anvils, providing a full distribution of particle fracture forces, typically fitted to a 2-parameter Weibull distribution.
- Purity Characterization:
- Magnetic Susceptibility (Ïv): Measurement of the magnetic dipole moment of the bulk sample in response to a magnetic field (H) to quantify the level of ferromagnetic transition-metal alloy inclusions (Fe-Ni) trapped during HPHT synthesis.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research demonstrates that the highest performing diamond requires exceptional purity and controlled geometryâqualities inherent to 6CCVDâs MPCVD materials. We offer engineered diamond solutions that eliminate the variability and metallic inclusion issues identified in traditional HPHT grit.
| Research Requirement | 6CCVD MPCVD Solution | Technical Advantage |
|---|---|---|
| Ultra-High Purity (Low Ïv) | Optical Grade SCD & High Purity PCD | MPCVD growth is catalyst-free, resulting in diamond with virtually zero metallic inclusions. This ensures maximum intrinsic strength, thermal stability, and toughness, far surpassing the Grade 1 HPHT material analyzed. |
| Controlled Geometry & Shape | Custom Laser Cutting & Shaping | Instead of relying on statistically distributed grit shapes, 6CCVD provides SCD/PCD plates that can be precision laser-cut into specific, repeatable geometries for arranged-diamond segments, eliminating shape variability and maximizing tool life. |
| Large Area Segments | PCD Plates up to 125mm | We offer Polycrystalline Diamond (PCD) wafers up to 125mm in diameter, enabling the manufacture of large, high-performance core bits and saw blades required for modern construction applications. |
| Precise Thickness Control | SCD/PCD Thickness Range | We supply SCD and PCD materials with thicknesses ranging from 0.1”m to 500”m, allowing engineers to select the optimal diamond volume for specific wear rates and application conditions. |
| Robust Segment Bonding | Custom Metalization Services | We provide in-house metalization (Au, Pt, Pd, Ti, W, Cu) tailored for robust bonding to metal matrices, ensuring superior adhesion and thermal management in high-stress drilling and sawing tools. |
| Surface Finish Requirements | Precision Polishing (Ra < 1nm) | For applications where surface finish is critical (e.g., polishing tools), 6CCVD guarantees ultra-low surface roughness (Ra < 1nm for SCD; Ra < 5nm for inch-size PCD). |
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend this research using materials optimized for maximum strength and purity:
- Optical Grade SCD: Recommended for applications requiring the highest possible purity, thermal stability, and compressive strength, ideal for high-precision inserts.
- High Purity PCD: Recommended for large-area segments where high toughness, large dimensions (up to 125mm), and superior thermal conductivity are required.
- Boron-Doped Diamond (BDD): Available for specialized applications requiring conductive diamond segments or electrodes.
Customization Potential
Section titled âCustomization Potentialâ6CCVD specializes in providing materials that meet exact engineering specifications. If your project requires unique dimensions, specific crystallographic orientations, or multi-layer metalization (e.g., Ti/Pt/Au stacks for brazing), our custom fabrication services ensure your diamond inserts are optimized for your specific tool design and application environment.
Engineering Support
Section titled âEngineering Supportâ6CCVDâs in-house PhD team offers expert consultation on material selection and characterization techniques. We can assist with defining the optimal material specifications (purity, thickness, geometry, and metalization) for high-performance drilling, sawing, and abrasive projects, leveraging the principles of particle characterization outlined in this study.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The last ten years have seen a step-change in the ability to position diamond particles in metalmatrix segments for drilling and sawing applications. Advances in segment assembly technology allow diamonds to be positioned at specific locations within the segment. Performance of the segment can be optimized when the diamond particles are themselves selected to best exploit arranged-diamond segment design and other cutting conditions (such as tool drive parameters). Diamond âgritâ products for stone and construction applications each comprise particles of various sizes, shapes, strengths and purities. Consequently, effective selection of diamond types is dependent upon measurement using appropriate laboratory âcharacterisationâ techniques. As many of these techniques yield results on individual particles rather than bulk âfigures-of-meritâ, effective interpretation of these results is dependent on appropriate statistical analyses. This paper will introduce the key characteristics of diamond products for construction applications, provide insights into appropriate laboratory characterisation techniques, and describe how their results may be best interpreted to facilitate understanding and consequent diamond selection.