Tuning the wettability of highly transparent Nb2O5 nano-sliced coatings to enhance anti-corrosion property

Abstract

In the present work, the deposition temperature-dependent optical, wetting and corrosion properties of niobium oxide (Nb2O5) coatings was investigated. The Nb2O5 thin films were deposited on two different substrates i.e. glass and stainless steel (SS 304) by using sputtering technique at various deposition temperatures (RT, 100 & 200 °C) in Ar:O2 (3:1) atmosphere. To confirm the pertinent growth of the prepared samples, X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were employed. The optical, wetting and corrosion studies of the synthesized samples were executed using UV Vis-spectroscopy (UV), contact angle (CA) and cyclic voltammetry (CV), respectively. The aquatic corrosion studies of Nb2O5 films deposited on SS samples were estimated under two dissimilar ways. The Tafel plot (polarization curve) and EIS (electrochemical impedance spectra) were accomplished in terms of polarization resistance (Rp) under saline water (3.5% NaCl aqueous solution) environment. Nano-sliced Nb2O5 film deposited at 200 °C on SS substrate exhibited excellent optical, good transparency, wetting and material protective behavior i.e. transmittance (~91%), refractive index (n) ~ 2.3045, hydrophobicity (θw) ~ 97.3°, corrosion rate ~ 6.9 × 10−3 mm/y and Rp ~ 2.78 × 106 Ω-cm2 in comparison to the other samples (coated and uncoated).