Effects of Laser Bionic Textures and Diamond-like Carbon Coatings on Tribological Properties of CuAl10Fe5Ni5 Under Oil Lubrication

At a Glance

Metadata	Details
Publication Date	2025-04-09
Journal	Coatings
Authors	Mengjiao Wang, Mingbo Zhu, Xiangkai Meng, Xudong Peng
Institutions	Zhejiang University of Technology
Citations	2
Analysis	Full AI Review Included

Expert Analysis: Effects of Laser Bionic Textures and DLC Coatings on CuAl10Fe5Ni5

Executive Summary

This research investigates a synergistic approach—combining laser bionic texturing and Diamond-Like Carbon (DLC) coatings—to drastically improve the tribological performance of CuAl10Fe5Ni5 aluminum bronze under oil lubrication.

Core Achievement: The combined textured DLC coating (S+T+D) achieved a 96% reduction in wear rate compared to the smooth substrate (S), demonstrating exceptional durability and stability.
Texture Optimization: Hexagonal bionic textures (inspired by python scales) proved superior to circular textures, attributed to enhanced oil retention and debris capture capabilities.
Friction Reduction (Texture Only): At high loads (15 N and 20 N), hexagonal texturing alone reduced the average friction coefficient by 25% and 16%, respectively, while reducing the wear rate by up to 64%.
DLC Dominance: DLC coatings provided the primary mechanism for wear resistance due to their high hardness and self-lubricating properties (sp²/sp³ carbon networks). Smooth DLC (S+D) reduced the wear rate by 95%.
Synergistic Mechanism: The textured DLC surface (S+T+D) leverages the high hardness of DLC alongside the hydrodynamic pressure generation and secondary lubrication provided by the hexagonal texture, ensuring continuous lubrication and effective debris management.
Stability Improvement: Both DLC-coated surfaces (S+D and S+T+D) exhibited consistently low and stable friction coefficients, eliminating the high fluctuations observed in the bare CuAl10Fe5Ni5 substrate.

Technical Specifications

Parameter	Value	Unit	Context
Substrate Composition (Al)	10.6	wt%	CuAl10Fe5Ni5 Aluminum Bronze
Counterface Hardness	700	HV	GCr15 Steel Ball
DLC Coating Thickness	1.74	µm	Deposited via Magnetron Sputtering (MS)
Transition Layer Thickness	0.44	µm	W transition layer
DLC Structure Ratio (I_D/I_G)	1.04	-	Indicates coexisting sp³ and sp² carbon networks
Circular Texture Diameter	90	µm	Bionic texture design
Hexagonal Outer Diameter	600	µm	Bionic texture design
Laser Power (Texturing)	8	W	Nanosecond laser texturing
Pulse Repetition Rate	25	kHz	Nanosecond laser texturing
DLC Reaction Gas	Isobutane (C₄H₁₀)	-	Used for carbon deposition
DLC Reaction Gas Flow Rate	16	cm³/min	Deposition parameter
Substrate Oil Contact Angle (S)	22	°	Wettability measurement
DLC Oil Contact Angle (S+D)	16	°	Optimal lipophilicity for continuous lubricating film
Friction Test Loads	5, 10, 15, 20	N	Reciprocating sliding test range

Key Methodologies

The study utilized a multi-step surface engineering process followed by rigorous tribological testing under oil lubrication conditions:

Substrate Preparation: CuAl10Fe5Ni5 samples were mechanically polished to achieve a surface roughness R_a of less than 0.08 µm, followed by ultrasonic cleaning in ethanol and acetone.
Laser Texturing: A nanosecond laser (YLP-20f) was used to create two bionic texture geometries (circular and hexagonal) on the substrate surface, optimizing parameters including 8 W power and 200 mm/s scanning speed.
DLC Coating Deposition: DLC films were deposited using Magnetron Sputtering (MS). A W transition layer (0.44 µm thick) was first applied, followed by the DLC layer (1.74 µm thick) using a graphite target and isobutane (C₄H₁₀) reaction gas.
Friction Testing: Reciprocating sliding friction tests were conducted using a CFT-1 ball-on-disk tribometer. A GCr15 steel ball (700 HV) served as the counterface. Tests were run at 5 Hz frequency and 5 mm stroke for 30 min under varying normal loads (5 N to 20 N).
Wear Analysis: Wear volume was measured using a 3D noncontact laser microscope to calculate the wear rate (W = ΔV / (F x L)).
Surface Characterization: SEM was used to analyze wear scar morphology. EDS mapping determined element transfer (or lack thereof) on the GCr15 ball. Raman spectroscopy confirmed the DLC structure (I_D/I_G ratio of 1.04).

Commercial Applications

The successful integration of laser texturing and DLC coatings on aluminum bronze provides significant commercial value across several high-performance engineering sectors:

Aerospace and Defense: Used in landing gear components and high-stress bearings where CuAl10Fe5Ni5 is already utilized, requiring enhanced durability and reduced maintenance cycles.
Automotive and Heavy Equipment: Application in internal combustion engine components (cylinder liners, piston rings) and industrial journal bearings, where the textured DLC surface ensures stable, low-friction operation under high loads and fluid lubrication.
Marine and Offshore Industry: Components exposed to corrosive environments (leveraging the bronze substrate’s corrosion resistance) that also require superior wear protection, such as mechanical seals and pump shafts.
Precision Machinery: Utilization in sliding guideways and high-precision mechanical seals where the stability of the friction coefficient and minimal wear debris generation are critical for long-term accuracy.
Surface Modification Services: This methodology establishes a robust, scalable process for upgrading existing bronze alloy components to meet modern tribological demands through combined laser processing and PVD/MS coating techniques.

View Original Abstract

Aluminum bronze (CuAl10Fe5Ni5) is widely utilized in engineering machinery because of its excellent castability and corrosion resistance. However, CuAl10Fe5Ni5 has been unable to meet increasingly demanding working conditions, so researchers have focused on improving its tribological properties. In this study, two bionic textures were designed on a CuAl10Fe5Ni5 surface via laser processing, and diamond-like carbon (DLC) coatings were subsequently deposited on these hexagonal textures. The tribological properties of textured surfaces and DLC coatings in conjunction with textures under various loads were examined through reciprocating friction tests conducted under oil lubrication conditions. The results demonstrate that the textured surface significantly enhances the stability of the CuAl10Fe5Ni5 alloy and effectively reduces friction and wear under various loading conditions. Hexagonal textures exhibit superior anti-friction and wear-resistant compared to other textures. The friction coefficients of the hexagonal textures at higher loads of 15 N and 20 N are 25% and 16% lower than those of the substrate, and the wear rates are 64% and 12% lower, respectively. DLC coatings further improve the tribological properties of CuAl10Fe5Ni5. The friction coefficients of DLC coatings and textured DLC coatings are 25% and 20% lower than those of the substrate, and the wear rates are 95% and 96% lower than those of the substrate, respectively. These results demonstrate that both textures and DLC coatings effectively enhance the tribological properties of CuAl10Fe5Ni5’s surface. The interaction mechanism between textures and DLC coatings can be attributed primarily to secondary lubrication, debris capture by the textures, self-lubricating properties, and increased surface hardness.

Tech Support

Original Source

DOI: https://doi.org/10.3390/coatings15040446

References

2018 - Tribocorrosion behaviour of aluminium bronze in 3.5 wt.% NaCl solution [Crossref]
2020 - Improvement of microstructure, tribology and corrosion characteristics of nickel-aluminum bronze by P/M method [Crossref]
2019 - Investigation of nickel aluminium bronze castings properties by degassing agent technique
2016 - Effects of heat treatments on microstructure and properties of nickel-aluminum bronze fabricated by centrifugal casting [Crossref]
2017 - Effect of heat treatment parameters on the structure and mechanical properties of aluminium bronze (Cu-10wt% Al)
2018 - Effect of nickel content on hardness and wear rate of surface modified cast aluminum bronze alloy
2018 - Thermal stability and corrosion resistance in a novel nickle aluminum bronze coating by laser cladding [Crossref]
2024 - Effect of picosecond laser surface texturing under babbitt coating mask on friction and wear properties of GCr15 bearing steel surface [Crossref]
2024 - Numerical and experimental investigation of textured journal bearings for friction reduction [Crossref]
2024 - The friction of surface textured cylinder liner segments modified by direct laser writing and direct laser interference patterning processes [Crossref]