A Comparative Study of Corrosion Resistance for HVAF-Sprayed Fe- and Co-Based Coatings

Abstract

There is an increasing demand to replace Co-based coatings with cheap and environmentally friendly Fe-based coatings in corrosive environments. The main objective of this work was to evaluate whether Fe-based coatings could present a better corrosion performance than Co-based coatings. Therefore, two types of Fe-based and one type of Co-based coatings with chemical compositions (in wt %) of Fe-28Cr-16Ni-1.85C (FeNiCrC), Fe-17Cr-12Ni (FeNiCr), and Co-28Cr-1C (CoCrC) were produced by High Velocity Air Fuel (HVAF) spraying. The corrosion behavior of the coatings was studied comparatively by electrochemical tests in 3.5 wt % NaCl solution at 25˝C. The polarization test results showed that the FeCrNiC coating protected the underlying substrate better than the CoCrC coating, while the FeCrNi coating failed to hinder the penetration of corrosive ions. Electrochemical impedance spectroscopy (EIS) measurements revealed that the solution penetrated into the coating through defects, however the corrosion process slowed down due to clogging of the interconnected defects by corrosion products. Increasing the in-flight average particle temperature from 1400˝C to 1500˝C led to a denser coating with fewer defects which seemed to improve the corrosion resistance of the FeCrNiC coating. The high-alloyed Fe-based coatings had the best corrosion protection performance and can thus be recommended as a potential alternative to Co-based coatings.

Effect of Graphene Oxide/ZSM-5 Hybrid on Corrosion Resistance of Waterborne Epoxy Coating

“…As shown in Figure 4a, ZSM-5 exhibited two intense crystalline peaks at 7 • -9 • and 23 • -25 • , which were the characteristic diffraction peaks of ZSM-5 [23]. The XRD pattern of ZSM-5-NH 2 was shown in Figure 4b and was similar to the pattern in Figure 4a.…”

“…A three-electrode cell consisting of a saturated calomel electrode (SCE) [23], a stainless-steel electrode and a coated coupon (WE) made up the Autolab test system (the surface area of CE is 0.12 cm 2 , and the surface area of WE is 9.07 cm 2 ). The signal amplitude was 10 mV relative to the open-circuit potential, and the frequency ranged from 10 -2 to 10 5 Hz.…”

Effect of SiO2 Dispersion on Chlorine-Induced High-Temperature Corrosion of High-Velocity Air-Fuel Sprayed NiCrMo Coating

“…formation of semi-melted particles, some of which do not plastically deform and entirely flatten over the surface [34]. Lack of peening effect is known to cause the formation of such features on the surface of HVAF coatings [35]. The rather wide distribution in particle size (-45+22 µm for NiCrMo-SiO2, and -45+15 µm for NiCrMo) is also a contributing factor, as the coarse particles present in the feedstock have a relatively greater tendency to remain unflattened.…”

Effect of Surface Pretreatment on Quality and Electrochemical Corrosion Properties of Manganese Phosphate on S355J2 HSLA Steel

“…The potentiodynamic polarization (PD) measurements and electrochemical impedance spectroscopy (EIS) measurements were realized by potentiostat VSP from BioLogic SAS France (equipment financed by the project ITMS 26220220048). EIS measurements were running under potential control with scanning frequency range 100 kHz-10 mHz [18]. The perturbation amplitude was 10 mV and stabilization time in NaCl solution was set to 5 min.…”