ICMCTF 2026 Session MC3-3-FrM: Tribology of Coatings and Surfaces for Industrial Applications III

Epoxy-based coatings play a critical role in the performance and reliability of semi-rigid packaging containers, where they must endure both mechanical forming stresses and tribological contact during service. This study examines the balance between coating brittleness, moulding stresses, and frictional behaviour, with the objective of improving coating solutions for industrial packaging applications.

Formulations were developed using bisphenol-A-based epoxy resin and phenolic resin cured with amine hardeners, with tailored additives to optimize flexibility and hardness. Coatings were applied and thermally cured under industrially relevant processing conditions. Mechanical performance was evaluated through bend, cupping, crosshatch adhesion, and impact resistance tests, simulating forming and handling stresses encountered in production. Results demonstrated that higher crosslink density, while enhancing hardness, increased brittleness and led to premature microcracking during deformation.

Tribological evaluation, performed using a multi-tribometer under dry sliding, revealed a strong correlation between brittleness and increased wear rates, with stiffer coatings exhibiting elevated coefficients of friction (COF) due to reduced surface compliance. Post-test analyses by profilometry and SEM confirmed brittle fracture-driven wear mechanisms such as micro-spallation and delamination.

These findings highlight the need for epoxy coatings engineered with a balance of hardness and flexibility, enabling them to survive forming operations while maintaining low wear and stable friction during service. The outcomes provide practical design guidelines for coating engineers to develop next-generation epoxy systems that improve both manufacturing reliability and end-use performance in semi-rigid container applications.

Keywords — Epoxy coatings, Tribology, Semi-rigid packaging, Industrial coatings.

While modern industries are becoming more sophisticated, diversified, and globalized, they requires the development of smart materials have multi-functionality, high mechanical properties, and extreme durability. Also they could be prepared environmentally friendly and energy efficiently. At the same point of view, the smart coating materials capable of simultaneously expressing various mechanical properties or opposite properties such as high hardness with high toughness, high electricity with high corrosion resistance are attracting attentions as an versatile and useful materials in the future. In particular, there is an urgent needs to develop a novel coating materials capable of stably maintaining microstructures and mechanical properties in various external environments, unlike conventional coating materials whose properties and structures are easily changed by the some harsh environments. To get this kinds of objects, the coating material with multi-components are essential. But if the materials should be prepared with one phase with multi components, they could have only one properties. So, nano-composites with various phases should be formed to realize the various properties. So, it is necessary to develop a coating layer composed of various components those could be formed various phases and more complex structures with multifunctional properties.

In this study, various single alloy target materials with various compositions based on the Zr-Cu amorphous materials have been prepared by powder metallurgy methods such as atomization, mechanical alloying, and Spark Plasma Sintering (SPS). The various nanocomposite coatings could be prepared by using single alloying targets. The most important property is the composition of the target material could be transferred to the coating layers. The properties of as-prepared nanocomposite coatings will be summarized in this present including the coating's performance under conditions that simulate EV drivetrain environments.

Graphene oxide exceptional solid lubrication properties, arising from its low shear strength and mechanical properties, make it an ideal material for tribological enhancement in biomedical implant surfaces. This study focusses on deposition of graphene oxide-molybdenum disulfide (MoS₂) composite coatings on laser-textured biomaterials such as commercially pure titanium and Nitinol substrates using the electrophoretic deposition (EPD) technique. Before EPD coating, substrates were treated with femtosecond laser texturing to produce both circular and bio-inspired micro-grooves morphologies, aimed at optimizing surface functionality. The tribological performance of the coated substrates were evaluated under dry sliding conditions using a ball-on-disc tribometer facility, while microstructural characterization were performed using SEM, EDS, XRD and Raman spectroscopy before and after wear testing. The results revealed that laser surface texturing significantly improved coating adhesion due to mechanical interlocking and enhanced tribological behavior, particularly in the case of bio-inspired patterns owing to better retention of graphene/MOS2 coating in the micro-grooves pattern. Additionally, EPD-prepared graphene oxide–MoS₂ composite coatings reduced the coefficient of friction to as low as 0.036 and markedly decreased wear rates compared to bare and EPD-coated GO/ MoS2 substrates. These findings demonstrate the strong potential of combining femtosecond laser texturing with graphene oxide -MoS₂ hybrid coatings to achieve ultra-low friction, high wear resistance, and durable biocompatible surfaces for advanced load-bearing biomedical implant applications.

Keywords: Biomedical Implants; Electrophoretic Deposition; Graphene oxide Nanoplatelets, MoS₂; Femtosecond laser texturing; Tribological property