ICMCTF 2025 Session IA2-2-TuM: Surface Modification of Components in Automotive, Aerospace and Manufacturing Applications II

Friction and wear-related failures are critical challenges for modern mechanical systems, affecting applications from microelectromechanical devices to automotive assemblies and biomedical implants. The pressing need to reduce these tribological failures has intensified efforts to design advanced coatings and lubrication solutions tailored to withstand extreme operating conditions. This presentation emphasizes our progress in the precise design of 2D material-based coatings, particularly those using graphene, molybdenum disulfide, and MXene, to achieve superlubricity—an ultra-low friction regime that greatly enhances component lifespan and efficiency.

By establishing a fundamental understanding of material interactions at sliding interfaces, we are able to develop coatings that not only improve performance but also contribute to the reliability and sustainability of tribological systems. These engineered coatings are evaluated for their tribological properties under a range of conditions, demonstrating that superlubricity can be achieved at the macroscale, under high contact pressure and shear conditions. We also propose experimental pathways to realize superlubricity in rolling-sliding contact conditions using solid-lubricant coatings, which could open new opportunities for industrial applications requiring highly durable, low-friction surfaces. Overall, this work lays the groundwork for next-generation tribologically optimized coatings, offering promising solutions for critical sectors reliant on advanced friction and wear management.

The need for superior physical, mechanical and tribological properties in modern industrial applications has driven manufacturers to develop advanced materials or provide tailor-made/innovative solutions for utilizing existing high performance materials. Aerospace and automotive industries are known to employ innovative materials like modern steels, titanium alloys, advanced ceramics etc., to meet the exponentially growing demand for ‘sustainable’ materials, taking into account industrial and economic viability. However, an exclusive solution addressing the increased adaptability of these materials is always inadequate owing to the excellent mix of inherent physical and mechanical properties. Although industry favors a ‘one solution’ to all materials/problems approach, it is practically impossible to implement it in real time. In this study, we aim to strategically propose solutions to enhance the tribo-mechanical properties of well-known, critical industrial materials like titanium, ceramics (alumina/Si) and advanced steels (Vancron/Vanadis) - through the synergistic effects of cold working and thermo-chemical processing.

The substrates of all the materials were subjected to simple finishing processes like grinding, turning/milling followed by controlled burnishing and shot peening/micro-blasting. Low temperature gas/plasma nitriding formed the last stage of pre-processing. Detailed tribological studies were carried out on all the samples. The nanoscale characterization of the pre-processed samples and the wear track via SEM/TEM revealed the formation of a thin ‘tribo zone’ with improved tribo-mechanical properties. The nature of tribo zone formed in each material, based on the type of cold working along with thermo chemical treatment will be outlined for all the materials and presented in the conference.

Acknowledgments

The support from the National Centre for Research and Development of Poland, Warsaw, Grant no. INNOGLOBO/II/60/CoatTool4.0-2023, aswellasthe National Science Center, Krakow, Poland, Grant no. SONATA UMO-2020/39/D/ST8/02610 are gratefully acknowledged.

Thermal spraying with liquid feedstock offers an exciting opportunity to obtain coatings with characteristics vastly different from those produced using conventional spray-grade powders. The two extensively investigated variants of this technique are Suspension Plasma Spraying (SPS), which utilizes a suspension of fine powders in an appropriate medium, and Solution Precursor Plasma Spraying (SPPS), which involves use of a suitable solution precursor that can form the desired particles in situ. The advent of axial injection high power plasma spray systems in recent times has also eliminated concerns regarding low deposition rates/efficiencies associated with liquid feedstock. The 10-100 µm size particles that constitute conventional spray powders lead to individual splats that are nearly two orders of magnitude larger compared to those resulting from the fine (approximately 100 nm - 2 µm in size) particles present in suspensions in SPS or formed in situ in SPPS. The distinct characteristics of the resulting coatings are directly attributable to the above very dissimilar ‘building blocks’ responsible for their formation. This talk will discuss the advancements in suspension and solution precursor thermal spraying associated with axial plasma spraying, with specific emphasis on thermal barrier coating (TBC) and environmental barrier coating (EBC) applications. Prospects of liquid feedstock thermal spraying for addressing some other niche applicationswill be discussed through some illustrative examples. A further extension of deploying solutions and suspensions that involves use of hybrid powder-liquid feedstock combinations for thermal spraying will also presented. This approach can be used to elegantly deposit coatings with unusual microstructures to develop a wide array of composite coatings. The possibilities unplugged by such hybrid feedstock processing will also be illustrated through case studies.