Microstructural characterization and wear behavior of plasma-sprayed Alumina-Titania coated SS 316L via SLM fabrication

Abstract This study investigates the microstructural characteristics and tribological performance of Alumina-Titania (Al 2 O 3 -TiO 2 ) plasma-sprayed coatings on SS 316L stainless steel fabricated using Selective Laser Melting (SLM). Plasma spray coating was employed to deposit a 250 μm-thick Alumina-Titania layer, enhancing surface properties. A microstructural analysis was conducted using Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersive x-ray Spectroscopy (EDAX) color mapping, x-ray Diffraction (XRD), Atomic Force Microscopy (AFM), and Electron Backscatter Diffraction (EBSD) to evaluate surface morphology, elemental distribution, and topographical characteristics. The wear performance was assessed by pin-on-disc wear testing at varying weights (5–30 N) and sliding velocities (0.32–0.96 m s −1 ) for duration of 3600 s, contrasting uncoated and coated samples. The findings revealed that the Alumina-Titania coating significantly reduced the wear rate and coefficient of friction (COF), showcasing outstanding tribological performance due to its high hardness, thermal stability, and reduced adhesive wear. The coated samples demonstrated reduced material loss, lower frictional force, and enhanced surface integrity compared to untreated SS 316L. Brinell hardness test confirmed a substantial increase in surface hardness for the coated samples, highlighting the mechanical reinforcement provided by the Alumina-Titania layer. These findings highlight the feasibility of ceramic-coated SLM-fabricated SS 316L for applications in biomedical implants, aerospace, and high-performance engineering components, where exceptional wear resistance and surface durability are critical.