Investigating the characterization and damping effects in thermally sprayed Al ₂ O ₃ –40% TiO ₂ ceramic coating

Ceramic coatings exhibit wear-resistant and damping characteristics that attenuate system vibrations, enhancing the overall surface performance of the system. This investigation involved a ceramic coating (Al 2 O 3 –40%TiO 2 ) deposition onto an SS 304 substrate through a thermally flame spraying process. The study encompassed the characterization of the surface morphology of the coated substrate using field emission scanning electron microscope and energy dispersive X-ray spectroscopy techniques. It was observed that the coating possesses a dense coating structure with fully melted regions and splat deposition and is uniformly distributed throughout the cross-section. The average measured microhardness surface roughness value was 812 HV and 2.55 µm, respectively. Furthermore, this study sought to experimentally determine the damping ratio for both the coated and uncoated substrates, and it aimed to evaluate their damping properties by analyzing the amplitude of the fast Fourier transform plot. The damping ratio for coated and uncoated substrates are 0.021316 and 0.016557 by the logarithmic decrement method, whereas 0.021174 and 0.016244 by the half-power bandwidth method, respectively. It was observed that coated material increases the damping ratio, increases the natural frequency, and ultimately increases the stiffness.