Niobium addition enhancing the corrosion resistance of nanocrystalline Ti5Si3 coating in H2SO4 solution

Abstract

nanocrystalline coatings were deposited onto Ti-6Al-4V substrates by a double glow discharge plasma technique. The effects of Nb alloying on the electrochemical behavior of the Ti 5 Si 3 nanocrystalline coatings were systematically investigated in a naturally aerated 5 wt.% H 2 SO 4 solution, for which various electrochemical techniques, including potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), potentiostatic polarization and Mott-Schottky analysis, were employed. Moreover, to evaluate the corrosion performance of the as-deposited coatings over an extended period, their corrosion resistance was analyzed after 7 days' immersion in a 5 wt.% H 2 SO 4 solution by EIS measurements and observations of corroded surface morphologies. The results showed that the Ti 62.5Àx Nb x Si 37.5 (x = 0, 6.3, 12.5) nanocrystalline coatings exhibit superior corrosion resistance compared with Ti-6Al-4V, and their corrosion resistance is enhanced with increasing Nb content, suggesting that Nb alloying is an effective strategy for improving the corrosion protection ability of the Ti 5 Si 3 nanocrystalline coating. The roles of Nb additions in enhancing the corrosion resistance of the Ti 5 Si 3 nanocrystalline coatings can be summarized as: (a) reducing the residual tensile stresses of the as-deposited coatings and (b) tailoring the composition, compactness and electronic structure of the passive films formed. These findings are expected to broaden the application of Ti 5 Si 3 as a highly corrosion-resistant coating for engineering components operating under aggressive conditions.

The Pseudo-Eutectic Microstructure and Enhanced Properties in Laser-Cladded Hypereutectic Ti–20%Si Coatings

“…These figures show that the corrosion resistance of the former is much higher than that of the latter. The results are consistent with previous research work in which the formation of the Ti-Si compound contributed to the increase of Ecorr, and a decrease in Icorr in Ti alloys corroded in a simulated body fluid [15][16][17]. In this study, it was also found that the laser-cladded material with a refined pseudo-eutectic microstructure has superior corrosion resistance to the cast material of the same composition.…”

Wear behavior and corrosion properties of Fe-based thin film metallic glasses

“…[53,55] , where E f is the formation potential for passive films. The thickness of the passive film formed on the Fe-based TFMG is estimated to be around 1.20 nm, which is relatively thicker than that on 304SS alloy (δ sc =0.96nm).…”

Plasma surface chromizing of P110 oil casing tube steel for improving corrosion and wear resistance purposes

“…Chromizing coating can also act as a barrier protecting P110 steel from the corrosive environments by its mechanical isolation effect [23][24][25][26]. Figure 7 shows the potentiodynamic polarization curves of P110 steel and chromizing coating in CO 2 -saturated simulated oilfield brine.…”