Intensive electro sintering of diamond composites with multicomponent Ni-Sn based binder

At a Glance

Metadata	Details
Publication Date	2016-01-01
Journal	Scientific Letters of Rzeszow University of Technology - Mechanics
Authors	R. S. Shmegera, В. І. Кущ
Analysis	Full AI Review Included

Technical Documentation: High-Performance Diamond Composites via Intensive Electro Sintering (IES)

Document Prepared by: 6CCVD Materials Engineering Team Focus: Analysis of IES technology for Diamond Composite Materials (DCM) using advanced Ni-Sn multicomponent binders. Applicable 6CCVD Products: Large Area PCD Wafers, Custom Metalized SCD/PCD.

Executive Summary

Intensive Electro Sintering (IES) technology presents a superior, energy-efficient method for manufacturing Diamond Composite Materials (DCM) compared to conventional high-temperature powder metallurgy.

Diamond Preservation: IES enables full consolidation at temperatures below 850°C and processing times in the range of tens of seconds, effectively eliminating diamond degradation (cracking and graphitization) associated with traditional methods (>1000°C).
Enhanced Binder Performance: The use of multicomponent Ni-Sn binders, combined with activating dopants (e.g., Cr) and refractory compounds (e.g., WC, TiC), forms intermetallic phases (Ni₃Sn) that act as hard reinforcing elements.
Superior Mechanical Properties: The resulting DCM exhibits significant increases in yield limit (up to 2.5x) and nanohardness (8.4 to 9.2 GPa), while retaining high macro-plasticity (up to 40% compressive deformation without fracture).
Optimized Interface Bonding: Chemical interaction between the binder and diamond results in a reliable adhesive bond strength of 300 MPa (at >700°C).
Thermal Management Breakthrough: Chromium (Cr) addition improves the diamond-to-matrix thermal contact conductivity tenfold (up to 2.3·10⁷ W/(m²·K)), a crucial factor for extending diamond tool lifespan and performance.
Process Efficiency: The IES method simplifies manufacturing by utilizing localized heating and transient processing, drastically reducing energy consumption compared to conventional vacuum sintering or hot pressing.

Technical Specifications

The following critical parameters and performance metrics were established through the IES process using the Ni-Sn multicomponent binder system.

Parameter	Value	Unit	Context
Max Sintering Temperature (T_max)	850 - 900	°C	Maintains original diamond quality; full reaction at 900°C achieved quickly.
Full Sintering Duration	30	seconds	Time required for completion of chemical reactions at 900°C.
Cold Pressing Pressure	300	MPa	Initial compaction leading to ~40% porosity.
IES Applied Pressure	150	MPa	Pressure applied during Intensive Electro Sintering.
IES Current Density	25	A/mm²	Current required to initiate rapid heating via resistance.
Ni Content in Binder	> 50	% mass	Main plastic component, oxidation resistant.
Sn Content in Binder	Up to 15	% mass	Activates liquid phase sintering, forming intermetallics.
Refractory Content (WC, TiC, TiB₂)	15 - 20	% mass	Further increases binder hardness and wear resistance.
Adhesive Bond Strength (Ni-Diamond)	300	MPa	Strength achieved at 700°C and above.
Nanohardness (Ni₃Sn phase)	8.4 - 9.2	GPa	Measured under 5 mN load, indicative of reinforcing phase strength.
Thermal Contact Conductivity (with Cr)	2.3·10⁷	W/(m²·K)	Optimized interface value due to Cr additive, critical for tool life.
DCM Macro-Plasticity Retention	40	%	Compressive deformation limit before cracking/fracture.

Key Methodologies

The highly accelerated fabrication of the high-quality Diamond Composite Material (DCM) relies on precise powder handling, compaction, and controlled electro-thermal loading.

Powder Mixture Preparation: Synthetic diamonds (ACT200 400/315) were combined with nickel, tin, refractory compounds (WC, TiC, TiB₂, etc.), and adhesion-active dopants (Chromium, Cr).
Mixing and Milling: The components were mixed using a rattler with hard metal balls in a dry grinding mode for 8 hours to ensure a uniform distribution.
Cold Pressing: The mixed powder was compacted via two-sided cold pressing at 300 MPa, achieving an initial compact porosity of approximately 40%.
Intensive Electro Sintering (IES): The green compact was subjected to simultaneous high mechanical load (150 MPa) and high current density (25 A/mm²).
Thermal Profile Control: Heating was rapid, reaching maximum temperatures (T_max) between 800°C and 900°C within 10 seconds, followed by a brief isothermal hold sufficient for the formation of desired intermetallic compounds (e.g., Ni₃Sn) and full consolidation (30 seconds total at 900°C).
Microstructure Analysis: X-ray microanalysis and SEM (Scanning Electron Microscopy) were used to confirm the formation of a homogeneous, pore-free structure and the prevalence of the hard Ni₃Sn intermetallic phase.
Property Evaluation: Thermal conductivity, macro/micro/nano hardness (using multiple indentation technique), and deformation curves were measured to confirm enhanced DCM quality.

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to support and advance research utilizing high-performance diamond composite fabrication methods like IES, particularly due to our core expertise in custom MPCVD diamond materials and precision metalization.

Applicable Materials for IES Research

Material Grade	6CCVD Relevance to IES	Customization & Advantage
Polycrystalline Diamond (PCD) Wafers	The paper utilizes synthetic diamond powder for DCM. 6CCVD offers large-area PCD substrates (up to 125mm in diameter) and plates, which can be processed and used as highly uniform, high-density source material for superior composite formation.	Custom sizes up to 125mm, thicknesses from 0.1 µm to 500 µm. Excellent input material for large-scale, high-integrity tool pre-forms.
Boron-Doped Diamond (BDD)	The IES process relies critically on the electrical conductivity of the compact (25 A/mm²). BDD is highly conductive, allowing researchers to potentially manipulate the required IES current density, optimize localized heating profiles, or create self-heating composite components.	Customizable doping levels to tune resistivity, facilitating precise thermal control during electro-sintering experiments.
High Purity Single Crystal Diamond (SCD)	For fundamental studies on diamond-binder interface physics and chemical reaction kinetics (e.g., verifying the 300 MPa Ni-diamond bond strength), highly polished SCD windows or plates offer superior, repeatable interfaces compared to powder/grit.	SCD available with Ra < 1 nm polishing; ideal for interface characterization, thermal barrier studies, and validating macro-kinetic models.

Metalization and Interface Engineering Support

The paper demonstrates that superior thermal and mechanical properties are achieved through optimized adhesion-active elements (Cr) deposited on the diamond surface, which dramatically improves contact thermal conductivity.

Custom Metalization Capability: 6CCVD offers in-house precision metalization services (Au, Pt, Pd, Ti, W, Cu) via e-beam evaporation and sputtering. This directly supports the research need for depositing active carbide/intermetallic forming elements (similar to the Cr mentioned in the paper) onto diamond surfaces prior to consolidation.
Precision Layer Control: We can provide diamond material pre-coated with custom, multi-layer metal stacks to optimize the chemical reaction kinetics during the rapid IES cycle, ensuring maximum adhesive strength (e.g., Ti adhesion layers followed by Ni-Sn reactive layers).
Laser Cutting and Shaping: 6CCVD provides custom laser cutting and shaping services, enabling researchers to produce complex component pre-forms (like those needed for drilling bits or tools) tailored for specific IES tooling geometries.

Engineering Support & Logistics

6CCVD’s in-house team of PhD material scientists specializes in thermal management and mechanical stability of diamond composites.

Material Selection Consulting: Our experts can assist research teams in selecting the optimal MPCVD material grade (SCD vs. PCD) and surface preparation (e.g., polishing, roughness, orientation) required to replicate or extend high-efficiency IES projects focused on High-Wear Diamond Tooling.
Global Supply Chain: We provide reliable global shipping (DDU default, DDP available) to ensure your cutting-edge IES research receives high-quality diamond materials promptly, anywhere in the world.

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

View Original Abstract

This paper deals with intensive electro sintering (IES) of diamond composite materials (DCM) with multicomponent Ni-Sn based binder.The effect of the powder mixture composition, activating dopants and IES technical parameters on the formation of the microstructure and physical, and mechanical properties of DCM is studied.It has been established that the leading densification mechanisms of IES involve thermally activated plastic deformation of nickel powder particles, tin melting, and infiltration and chemical interaction of components.The presence of a liquid phase during the electro sintering increases conductivity of powder compact and intensity of heating which, in turn, significantly increases shrinkage rate and promotes uniform distribution of components and formation of intermetallic compounds.The macro-kinetic model of intermetallic compounds formation in the Ni-Sn system in non-isothermal conditions and the model of DCM with structured matrix and imperfect interface have been developed.The thermal and mechanical properties of electro sintered DCM have been evaluated.The initial mixture composition and the IES technological parameters promising in terms of DCM quality have been found.The proposed method of manufacturing the drilling bits by IES constitutes a potential basis for the industrial production technology of diamond tools.

Tech Support

Original Source

DOI: https://doi.org/10.7862/rm.2016.13