Study of composition of the ultrafine material produced from graphite–catalyst mixture under extreme energy action
At a Glance
Section titled “At a Glance”| Metadata | Details |
|---|---|
| Publication Date | 2016-11-01 |
| Journal | Journal of Physics Conference Series |
| Authors | N. V. Melnikova, Denis Alikin, Yu B Melnikov, И. Г. Григоров, S. A. Chaikovsky |
| Institutions | Ural Federal University, Institute of High Current Electronics |
| Citations | 1 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: Extreme Energy Synthesis of Ultrafine Carbon Materials
Section titled “Technical Documentation & Analysis: Extreme Energy Synthesis of Ultrafine Carbon Materials”Executive Summary
Section titled “Executive Summary”This study investigates the creation of ultrafine carbon materials, including diamond-like carbon (D-LC), via electrical explosion of graphite/catalyst (Ni-Mn) mixtures under extreme energy conditions (megaampere currents). This research validates a high-energy synthesis pathway but underscores the significant advantages of controlled MPCVD synthesis for purity and scale.
- Synthesis Method: Ultrafine carbon materials (1-1000 nm) were synthesized using high-current electrical explosion (2-2.5 MA, 100 ns rise time) of a 50/50 wt % graphite-Ni/Mn catalyst mixture.
- Key Phase Identification: The presence of diamond-like carbon was confirmed primarily via Laser Confocal Raman Spectroscopy, exhibiting the characteristic diamond band shift at approximately 1330 cm-1.
- Material Structure: The resulting product is a highly heterogeneous composite comprising three primary fractions: graphite fragments, amorphous carbon, and ultrafine faceted D-LC particles or agglomerates (sized < 250 nm).
- Conductivity: Electrical properties varied drastically by sample location; films dominated by residual metal particles showed low resistance (≈ 500 Ω), while films with smaller, purer carbon particles exhibited typical dielectric behavior.
- Research Limitation: The researchers noted that characterizing the crystal structure and electronic features of the low-concentration, sub-250 nm D-LC particles requires highly advanced techniques (TEM, ultrasoft X-ray spectroscopy) due to interference from the mixed metal/graphite matrix.
- 6CCVD Value Proposition: 6CCVD offers highly purified Single Crystal (SCD) and Polycrystalline (PCD) diamond, providing researchers with phase-pure material necessary to decouple intrinsic diamond properties from synthetic matrix effects.
Technical Specifications
Section titled “Technical Specifications”| Parameter | Value | Unit | Context |
|---|---|---|---|
| Synthesis Current Amplitude | 2.0 - 2.5 | MA | MIG high-current generator output |
| Current Rise Time | 100 | ns | Speed of energy application |
| Precursor Mixture | 50/50 | wt % | Graphite / Ni-Mn Catalyst ratio |
| Synthesized Particle Size Range | 1 - 1000 | nm | General size range of ultradispersed material |
| Confirmed D-LC Particle Size | ≤ 250 | nm | Size of faceted particles/agglomerates |
| Diamond Raman Peak (D Band) | ≈ 1330 (1332) | cm-1 | Confirms sp3 (diamond-like) bonding |
| Graphite Raman Peak (G Band) | 1582 | cm-1 | Confirms sp2 (graphite) bonding |
| Highly Conductive Resistance (Sample 1) | ≈ 500 | Ohm | Caused by continuous metal matrix |
| Dielectric Resistance (Samples 2/3) | ≈ 107 | Ohm·mm | Weakly conductive, carbon-dominant film |
| Predicted Lonsdalite Formation Pressure | 30 - 70 | GPa | Extreme energy conditions required |
Key Methodologies
Section titled “Key Methodologies”The synthesis and characterization relied heavily on achieving extreme pressure/temperature conditions and utilizing multiple spectroscopy techniques to resolve the heterogeneous mixture.
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Extreme Synthesis (Electrical Explosion):
- A MIG high-current generator delivered extreme energy pulses (2-2.5 MA) through copper tubes filled with the precursor mixture (Graphite, Ni-Mn).
- The catalyst (Ni-Mn, 50/50 wt %) facilitates carbon phase transformation under high pressure.
- Products were collected by precipitation onto glass substrates placed 41-42 cm from the exploded load.
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Structural and Compositional Analysis:
- X-Ray Diffraction (XRD): Used for initial phase identification of copper, nickel, graphite, and diamond-like crystalline structures.
- Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS): Used to image particle morphology (spherical, faceted) and map elemental distribution (C, Ni, Fe, Cu). Confirmed the presence of < 250 nm faceted particles suspected to be D-LC.
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Electrical Property Measurement:
- Impedance Spectroscopy (Solartron 1260A): Used to measure electrical conductivity and resistance, differentiating between highly conductive metallic fractions and dielectric carbon/diamond-like fractions.
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Phase Purity Confirmation:
- Laser Confocal Raman Microscopy (Alpha 300 R): Employed specifically to confirm the presence of highly symmetric carbon bonds. The detection of the band near 1330 cm-1, even with low concentration, provided definitive evidence of the nanocrystalline diamond-like phase.
6CCVD Solutions & Capabilities
Section titled “6CCVD Solutions & Capabilities”The study successfully demonstrates an ability to create nanodiamond structures under explosive conditions. However, the resulting heterogeneity and the need for subsequent complex analysis (TEM, ultrasoft X-ray) highlight the fundamental advantage of controlled, high-purity MPCVD diamond for demanding applications and fundamental research.
| Paper Requirement/Limitation | 6CCVD Solution & Capability | Advantage for Researcher |
|---|---|---|
| Heterogeneity/Impurity (Metal contamination, amorphous C, graphite) | Optical Grade Single Crystal Diamond (SCD): Offers intrinsic purity levels necessary for reliable analysis of electronic band structure and crystal parameters (as required in the paper’s conclusion). | Decouples intrinsic diamond properties from synthesis matrix effects, ensuring high-fidelity data extraction. |
| Ultrafine Size Constraint (< 250 nm particles, low concentration) | Custom Dimensions and Thickness Control: MPCVD allows precise control over thickness (0.1 µm to 500 µm SCD/PCD) and area (up to 125 mm wafers). | Provides bulk material for macro-scale testing (e.g., robust impedance or heat transfer studies) and film-level studies without substrate interference. |
| Need for Advanced Characterization (TEM, Ultrasoft X-ray to confirm structure) | High-Quality Polycrystalline Diamond (PCD): Offers nanocrystalline structure without the pervasive metallic contaminants found in the synthesis method. | Enables direct study of nanocrystalline/ultrananocrystalline properties using standard Raman/SEM without needing extreme post-processing purification. |
| Material Testing Interface (Metal particle matrix interferes with electrical tests) | Integrated Metalization Services (Au, Pt, Pd, Ti, W, Cu): We provide customized contact pads and thin films directly onto high-purity diamond plates. | Delivers reliable, stable electrical contacts for impedance and conductivity studies, eliminating interference from uncontrolled, exploded metal particles. |
| Polishing Requirements (Surface analysis of faceted particles) | Ultra-Smooth Polishing: Achievable surface roughness Ra < 1 nm (SCD) or Ra < 5 nm (Inch-size PCD). | Essential for high-resolution analysis (AFM/SEM) and integrating diamond into sensitive microelectronic devices. |
Engineering Support
Section titled “Engineering Support”6CCVD’s in-house team of PhD material scientists and technical engineers specialize in tailoring diamond substrates for high-energy density and electronic applications. We assist researchers in replicating or extending this type of extreme synthesis research by providing certified, phase-pure SCD and PCD templates that act as reliable baselines for comparing novel synthesized materials, or for use in high-power electronic devices where purity is paramount.
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. Global shipping (DDU default, DDP available) ensures rapid delivery of specialized CVD diamond worldwide.
View Original Abstract
Ultrafine materials were produced under conditions of extreme energy effects on the mixture of graphite and Ni-Mn catalysts. For the purpose to obtain various forms of carbon, including diamond-like forms, experiments were performed on a MIG high-current generator with the current amplitude of 2-2.5 MA and current rise time of 100 ns. The composition of the explosion products was studied using x-ray diffraction and x-ray phase analyses, the impedance spectroscopy, optical and scanning electron microscopy, x-ray microanalysis and energy dispersive x-ray analysis and the laser confocal Raman microscopy. It was found that the carbon in the studied materials is in the graphite, diamond-like (the faceted particles or agglomerates of faceted particles in size about or less than 250 nm) and amorphous forms.