Transition metal based plasma sprayed coatings for tribological applications

Plasma spraying has emerged as a key technology in surface engineering, providing an efficient route to produce advanced coatings with tailored microstructures and superior tribological performance. This review highlights recent developments in plasma-sprayed transition metal–based coatings for tribological applications, focusing on the interplay between coating composition, microstructure, and wear mechanisms. Load-bearing Ni and Fe based matrix coatings offer structural support and toughness, accommodating hard reinforcements to enhance wear resistance under mechanical stress. Co and Mo containing coatings exhibit high-temperature stability, hardness retention, and resistance to adhesive and abrasive wear, making them suitable for severe operating conditions. Cu based coatings act as solid lubricating layers, reducing friction and improving durability in sliding contacts. The review also discusses the role of reinforcing agents, powder design, and plasma spraying parameters in achieving dense, well-adhered coatings with optimized frictional and mechanical behavior. Overall, the functional integration of these transition metal systems demonstrates the potential of plasma-sprayed coatings to deliver multifunctional, durable, and energy-efficient surfaces for next-generation tribological systems.