Preparation of Diamond Nanofluids and Study of Lubrication Properties

At a Glance

Metadata	Details
Publication Date	2025-04-30
Journal	Materials
Authors	Jiamin Yu, Junhao Wu, Chengcheng Jiao, Huanyi Chen, Xinxin Ruan
Institutions	Chinese Academy of Sciences, Kogakuin University
Citations	2
Analysis	Full AI Review Included

Technical Documentation & Analysis: MPCVD Diamond for Advanced Tribology

Source Paper Analysis: Preparation of Diamond Nanofluids and Study of Lubrication Properties (Yu et al., Materials 2025)

Executive Summary

This research validates the exceptional tribological performance of functionalized two-dimensional (2D) diamond nanosheets (SCND-KH560-M2070) when used as lubricant additives. The findings underscore the potential of high-purity, engineered diamond materials in next-generation lubrication systems.

Core Achievement: Successful preparation of solvent-free, fluidized 2D diamond nanofluids via covalent grafting of polyether amine (M2070) and organosilane (KH560) onto diamond nanosheets.
Dispersion Stability: The functionalization process effectively addressed the critical challenge of poor dispersion stability inherent to nanomaterials in lubricants.
Optimal Performance: The 185 nm nanosheets demonstrated superior performance, achieving the lowest coefficient of friction (COF).
Extreme Friction Reduction (Dry): Under dry friction conditions, the optimal nanofluid reduced the COF by 94.7% (to 0.025) and the wear rate by 96% compared to unlubricated steel.
Lubricant Additive Efficacy: When added at 3 wt% concentration to a water-glycol solution, the nanofluid reduced COF by 66.9% and wear volume loss by 81.8%.
Mechanism: Lubrication is achieved through the formation of a stable, elastic, and wear-resistant protective diamond film on the friction surface, enabled by the functionalized polymer layers.

Technical Specifications

The following hard data points were extracted from the tribological testing and material characterization:

Parameter	Value	Unit	Context
Optimal Nanofluid Size	185	nm	Achieved lowest COF (0.025)
Optimal Additive Concentration	3	wt%	In H₂O-C₂H₆O₂ solution
Dry Friction COF (Minimum)	0.025	N/A	94.7% reduction vs. unlubricated steel (0.52)
Water-Glycol COF (Minimum)	0.16	N/A	66.9% reduction vs. pure H₂O-C₂H₆O₂ (0.46)
Dry Friction Wear Reduction	96	%	Compared to unlubricated AISI 52100 steel
Water-Glycol Wear Reduction	81.8	%	Compared to pure H₂O-C₂H₆O₂
Fixed Applied Load	5	N	Constant load during friction test
Fixed Frequency	5	Hz	Frequency of friction test
Steel Ball Material	GCr15	N/A	Diameter 6 mm, Surface Roughness (Ra) 6 nm
Steel Plate Material	AISI 52100	N/A	Size 2 x 2 x 1 cm³, Ra 12.9 nm
Diamond Nanosheet Characteristic Peak	1325	cm^-1	Raman spectroscopy (SCND)
Organic Shell Content (TGA)	11.05	wt%	Mass fraction of stable SCND in nanofluid
Thermal Stability (SCND)	300	°C	Temperature before organic shell decomposition

Key Methodologies

The solvent-free, 2D diamond nanofluid (SCND-KH560-M2070) was prepared and tested using the following key steps:

Intermediate Synthesis (KH560-M2070):
- KH560 (5 wt%) and M2070 (10 wt%) ethanol solutions were mixed.
- Continuous stirring at 50 °C for 12 hours to form covalent bonds.
Grafting Reaction:
- Pre-dispersed diamond nanosheets (SCND, 0.5 g) were mixed into the intermediate solution.
- Grafting reaction carried out at 45 °C for 6 hours.
Purification and Drying:
- Mixture purified via 3-day dialysis (MWCO 8 kDa) to remove unreacted M2070.
- Solvent removed via rotary evaporation.
- Final product vacuum-dried at 60 °C for 72 hours.
Characterization:
- Morphology: SEM, TEM, EDS.
- Structure/Chemistry: FTIR, Raman, XRD, XPS.
- Thermal/Rheological: TGA (up to 1000 °C under N₂), DSC, Rheometer.
Tribological Testing:
- Equipment: Multifunctional High-Temperature Friction and Wear Tester (UMT-3).
- Configuration: Ball-on-plate (GCr15 ball vs. AISI 52100 plate).
- Conditions: 5 N load, 5 Hz frequency, 30 min duration, 5 mm stroke length, 50 mm/s sliding speed.
- Analysis: 3D optical profiler used to measure wear tracks and calculate wear volume.

6CCVD Solutions & Capabilities

This research highlights the critical role of high-quality diamond materials in advanced tribology and lubrication. 6CCVD is uniquely positioned to support the replication and extension of this work, particularly in scaling up production and testing under industrial-relevant, extreme conditions.

Applicable Materials for Tribology Research

The diamond nanosheets (SCND) used in this study are derived from bulk diamond. 6CCVD provides the highest purity precursors and finished diamond components necessary for next-generation tribological systems:

6CCVD Material	Application Relevance	Customization Potential
Optical Grade SCD	Precursor for ultra-high purity nanodiamond synthesis (SCND) where structural integrity is paramount. Ideal for high-precision, low-defect studies.	SCD thickness control from 0.1 µm up to 500 µm.
High-Purity PCD	Substrates for testing nanofluids under extreme pressure/load conditions, offering superior mechanical and thermal stability compared to steel.	Plates/wafers up to 125 mm in diameter.
BDD (Boron-Doped Diamond)	Electrodes or specialized friction pairs where simultaneous electrochemical analysis (in situ characterization, as suggested for future work) is required.	Custom doping levels and thicknesses (0.1 µm to 500 µm).

Customization Potential for Advanced Testing

The paper explicitly notes limitations in testing under specific load, frequency, and temperature ranges. 6CCVD’s manufacturing capabilities directly address these limitations, enabling researchers to move toward real-world industrial applications:

Custom Dimensions & Substrates: We provide large-area PCD wafers (up to 125 mm) and thick SCD substrates (up to 10 mm) for constructing robust, high-load friction pairs, far exceeding the small steel plates used in the current study.
Ultra-Low Roughness Polishing: For studies requiring precise control over the substrate surface interaction, 6CCVD offers industry-leading polishing:
- SCD: Ra < 1 nm
- Inch-size PCD: Ra < 5 nm
Integrated Metalization Services: For researchers integrating diamond components into complex systems (e.g., sensors for in situ characterization during friction), we offer internal metalization capabilities, including Ti, Pt, Au, Pd, W, and Cu layers, ensuring robust electrical contacts and adhesion.

Engineering Support & Future Research

6CCVD’s in-house PhD team specializes in the material science of MPCVD diamond and can assist researchers in overcoming the challenges identified in the paper’s conclusion:

Extreme Environment Testing: We provide material consultation for designing tribological test setups involving high temperatures and heavy loads, ensuring the diamond components maintain integrity.
Material Selection for Nanodiamond Precursors: Our experts can advise on selecting the optimal SCD or PCD precursor material to maximize the yield and quality of 2D diamond nanosheets (SCND) for functionalization.
Global Logistics: We ensure reliable, global shipping (DDU default, DDP available) of high-value diamond materials, supporting international research collaborations.

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

View Original Abstract

As an emerging two-dimensional nanomaterial, diamond nanosheets have the advantages of high hardness and chemical stability; exhibiting good tribological properties when used as lubricant additives. However, the dispersion stability of nanomaterials as additives in lubricants remains a significant challenge. In this study, fluidized and functionalized diamond nanofluids were prepared by grafting polyether amine on the surface of diamond nanosheets. By changing the state of diamond nanosheets, this material not only improved its own lubrication property, but also improved its dispersion in the lubricant. The friction test results demonstrated that the friction coefficient was reduced by 66.9% and the wear rate was reduced by 81.8% with the addition of 3 wt% of diamond nanofluid in water-glycol solution. This enhancement of lubricating properties is related to the excellent film-forming properties of diamond nanofluids during the tribology. This indicates that fluidized 2D diamond nanosheets have excellent lubricating properties and can significantly improve the friction properties of lubricants as additives.

Tech Support

Original Source

DOI: https://doi.org/10.3390/ma18092052

References

2017 - Influence of tribology on global energy consumption, costs and emissions [Crossref]
2019 - Tribology of two-dimensional materials: From mechanisms to modulating strategies [Crossref]
2022 - Nanodiamond plates as macroscale solid lubricant: A “non-layered” two-dimension material [Crossref]
2020 - Optimization of groove texture profile to improve hydrodynamic lubrication performance: Theory and experiments [Crossref]
2023 - Functionalized carbon nanostructures as lubricant additives—A review [Crossref]
2011 - Effect of aggregation on the viscosity of copper oxide-gear oil nanofluids [Crossref]
2021 - Mechanical properties and wear resistance of industrial bearing liners in concentrated boundary-lubricated sliding [Crossref]
2024 - The tribological properties of nano-lubricants and their application on bearings: Recent research progress
2023 - Molecular dynamics simulation of the Stribeck curve: Boundary lubrication, mixed lubrication, and hydrodynamic lubrication on the atomistic level [Crossref]
2021 - Numerical and Experimental Studies on Performance Enhancement of Journal Bearings Using Nanoparticles Based Lubricants [Crossref]