Development of Electroplated Diamond Saw Wire by Novel Electroplating Technique

At a Glance

Metadata	Details
Publication Date	2017-01-01
Journal	Journal of the Japan Society for Precision Engineering
Authors	Tsunehisa Suzuki, Jun-ichi MURAOKA
Analysis	Full AI Review Included

High-Performance CVD Diamond Solutions for Advanced Slicing Technology

Technical Analysis of CNT-Nickel Composite Electroplated Diamond Wire

Prepared for Engineers and Scientists by 6CCVD R&D

Executive Summary

The analyzed research paper presents a groundbreaking approach to enhancing the performance and longevity of electroplated diamond saw wire, crucial for the high-efficiency slicing of hard, brittle materials like single crystal silicon (Si), silicon carbide (SiC), and sapphire.

Core Innovation: Utilization of a Nickel-Carbon Nanotube (Ni-CNT) composite layer as the bonding matrix for abrasive diamond particles, significantly improving grain retention strength.
Mechanical Enhancement: The Ni-CNT composite coating achieved a Vickers hardness of approximately 600 HV, a 2-to-3-fold improvement over standard electroplated Ni (~200 HV).
Wear Resistance: The CNT-reinforced matrix demonstrated a 3x improvement in wear resistance compared to standard Ni plating in reciprocating friction tests.
Abrasive Retention: Grain bonding strength (shear test) was improved by approximately 1.5 times when comparing 5µm Ni-CNT to 5µm standard Ni plating.
Tool Life Extension: In single crystal Si cutting tests (10mm width), the Ni-CNT wire achieved a cutting distance of approximately 700 µm, demonstrating a tool life 10 times greater than the standard Ni-plated wire (~50 µm).
Slicing Quality: Extended tool life reduced micro-cracking and brittle fracture, leading to improved surface quality and reduced damage layer formation on the cut Si wafer surfaces.

Technical Specifications

Parameter	Value	Unit	Context
Max Vickers Hardness (Ni-CNT)	~600	HV	Achieved with optimized CNT vol%
Standard Ni Hardness	~200	HV	Comparison baseline
Wear Resistance Improvement	~3	times	Ni-CNT vs. standard Ni (reciprocating friction test)
Abrasive Retention Improvement	~1.5	times	Ni-CNT (5µm) vs. Standard Ni (5µm)
Cutting Speed (V_f)	0.6	mm/min	Feed rate for single crystal Si slicing
Grinding Speed (V)	13.5	m/min	Wire reciprocating speed
Wire Tension (T)	5.0	N	Required tension during slicing test
Si Slicing Distance (Ni-CNT)	~700	µm	Distance before tool failure/brittle failure onset
Si Slicing Distance (Standard Ni)	~50	µm	Distance before tool failure/brittle failure onset
Tool Life Extension	10+	times	Based on maximum ductile slicing distance comparison
Plating Current Density	15	A/dm²	Ni-CNT composite electroplating parameters
Plating Bath Temperature	45	°C	Ni-CNT composite electroplating parameters
CNT Diameter (Nanocyl NC7000)	~10	nm	Multi-Walled Carbon Nanotube (MWCNT) filler size

Key Methodologies

The enhanced performance relies on stabilizing the CNT dispersion and embedding them uniformly within the nickel matrix during the electroplating process, resulting in a dense, nano-crystalline composite.

Preparation of Plating Bath: A Nickel Sulfamate (Ni(NH₂SO₃)₂) bath was prepared, containing key components such as NiCl₂·6H₂O and H₃BO₃.
CNT Dispersion: Multi-walled Carbon Nanotubes (MWCNTs, Nanocyl NC7000) were added to the bath. Ultrasonic agitation was utilized throughout the plating process, which was crucial for preventing CNT aggregation and ensuring uniform, single-dispersion incorporation into the plating matrix.
Composite Formation: The incorporated CNTs act as heterogeneous nucleation sites, accelerating the crystallization rate and resulting in an ultra-fine, nano-crystalline Ni grain structure (tens of nanometers). This structure, combined with CNT reinforcement, is the primary driver for the increased hardness and reduced porosity.
Wire Structure Plating: The diamond saw wire was fabricated with three distinct layers on a 0.1 mm diameter piano wire core:
- Strike Plating Layer: Initial bonding layer on the piano wire.
- Underlayer (T₂): 4 µm thick standard Ni plating.
- Finish Layer (T₁): 2 µm thick layer of either standard Ni or the high-performance Ni-CNT composite plating, applied as the outermost layer to retain the diamond grains.
Abrasive Integration: Ni-coated diamond abrasive particles (10-20 µm) were embedded and fixed by the electroplating process.

6CCVD Solutions & Capabilities

The research demonstrates the critical role of material quality and precision engineering in developing robust tools for advanced materials processing. 6CCVD is uniquely positioned to supply the foundational and complementary materials required to replicate, scale, and extend this research into next-generation wafer production (SiC, GaN, high-purity diamond).

Applicable Materials for Advanced Slicing Research

The increasing demand for thin, large-area wafers requires high-throughput, low-damage slicing solutions. 6CCVD provides the core CVD diamond materials necessary for this work.

6CCVD Material	Application Relevance	Customization Potential
Optical Grade SCD	High-purity, low-defect single crystal diamond required for advanced electronics, quantum computing substrates, and optical windows. Researchers rely on precision slicing of these materials.	Wafers up to 125mm in size, minimum thickness of 0.1 µm.
Electronic Grade SCD	Essential for producing high-power, high-frequency devices where low internal stress and controlled defect density are critical.	Substrates up to 10mm thick, Ra < 1nm polishing.
Heavy Boron Doped (BDD) PCD/SCD	If the research extends to electrochemical machining (EDM) or specialized tooling (which often uses BDD as a highly wear-resistant electrode), 6CCVD can supply heavily B-doped diamond.	Customized doping levels (conductivity control) and thicknesses up to 500 µm.

Customization Potential for Tool Development

The paper highlights the need for precise layer control (µm scale) and specific material integration. 6CCVD’s in-house capabilities directly support researchers aiming to optimize diamond tool performance:

Custom Dimensions and Thinning: While the wire core is 0.1 mm, high-performance slicing relies on producing wafers up to 125 mm. 6CCVD specializes in cutting, shaping, and thinning SCD/PCD to custom dimensions for both substrate use and tool manufacturing.
Precision Metalization Services: The stability of the diamond abrasive often requires stable interface layers. 6CCVD provides advanced metalization capability, offering custom sputtering of Ti, Pt, Au, Pd, W, and Cu layers. This is critical for improving adhesion in composite matrices or preparing diamond surfaces for subsequent brazing/bonding steps.
Ultra-Smooth Polishing: Our SCD polishing capability achieves surface roughness Ra < 1nm. For PCD materials, we achieve Ra < 5nm on inch-sized wafers, ensuring high-quality surface finish for testing cutting tool performance interfaces.

Engineering Support

The successful fabrication of the high-performance saw wire required complex materials engineering, specifically in composite matrix design and control of the electroplating environment.

6CCVD’s in-house PhD team provides consultative support for projects involving the processing of hard, brittle materials. We assist engineers and scientists in optimizing material selection and handling for precision slicing, grinding, and surface modification projects—critical steps in transforming bulk MPCVD diamond into functional devices.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. (Global shipping available, DDU default with DDP options.)

Tech Support

Original Source

DOI: https://doi.org/10.2493/jjspe.83.820