The Corrosion and Wear-Corrosion of the Iron-Base Amorphous Coating Prepared by the HVOF Spraying

Abstract

In this work, the corrosion behaviors of an iron-based amorphous coating produced by high-velocity oxy-fuel (HVOF) spraying were investigated. Potentiodynamic and potentiostatic polarization and corrosion pin-on-ring (corrosion-wear) tests were conducted to evaluate the corrosive properties of the coating as compared with the 316L substrate. The corrosion behaviors of the 316L substrate and coated sample were tested in 3.5 wt.% NaCl, 1 M HCl, and 0.5 M H2SO4 solutions. In the 3.5 wt.% NaCl and 1 M HCl solutions, the corrosion resistance of the coating was a little inferior or equivalent to that of the 316L substrate after potentiodynamic polarization tests. In the 0.5 M H2SO4 solution, the two tested samples exhibited wide passivated zones in the polarization curves. In such a mild acid, the corrosion resistance of the 316 substrate was superior to that of the amorphous coating, possibly due to the presence of defects in the coating. After potentiodynamic polarization tests, the linkage of initial fine pits into large, deep pores was seen in the corroded 316L substrate. By contrast, extensive corrosion along with preferentially corroded defective sites was seen in the coating. Moreover, the coating exhibited a much higher resistance to corrosion-wear, or low weight loss, in 3.5 wt.% NaCl solution. After the corrosion-wear tests, deep furrows were present in the 316L substrate, whereas a rubbed smooth surface and a corroded zone were seen in the coating. The greater weight loss of the 316L substrate confirmed its poor resistance to corrosion-wear relative to the amorphous coating in 3.5 wt.% NaCl solution.

Corrosion Resistance of Fe-Based Amorphous Films Prepared by the Radio Frequency Magnetron Sputter Method

“…Table 1 lists the corrosion potential (ECorr), corrosion current density (iCorr), and pitting potential (EPit) of the tested samples. In our prior work [38] studying the corrosion performance of the HVOF coating using the same amorphous powder as used in this work, a 1 M HCl solution was a much more severe corrosion condition relative to seawater and 0.5 Potentiodynamic polarization tests of various specimens were performed at room temperature in a 1 M HCl solution, and the polarization curves are shown in Figure 4. Table 1 lists the corrosion potential (E Corr ), corrosion current density (i Corr ), and pitting potential (E Pit ) of the tested samples.…”

“…Table 1 lists the corrosion potential (E Corr ), corrosion current density (i Corr ), and pitting potential (E Pit ) of the tested samples. In our prior work [38] studying the corrosion performance of the HVOF coating using the same amorphous powder as used in this work, a 1 M HCl solution was a much more severe corrosion condition relative to seawater and 0.5 M H 2 SO 4 . To distinguish the corrosion resistances among the IN 600, C276, and amorphous film, a 1 M HCl solution is used in this work.…”

“…An Fe-based (FeMoCrYCB) thin film in an artificial sweat solution shows much superior passivation stability relative to 304 SS [37]. In prior work [38], an Fe-based AA (FeCrNiMoCSiB) was used as the feedstock powder for HVOF spraying on a 316L plate. The corrosion rate of the high-velocity oxy-fuel (HVOF) coating is identical to that of the 316L SS in seawater and a 1 M HCl solution, but much higher corrosion-wear resistance was observed in seawater [38].…”

“…In prior work [38], an Fe-based AA (FeCrNiMoCSiB) was used as the feedstock powder for HVOF spraying on a 316L plate. The corrosion rate of the high-velocity oxy-fuel (HVOF) coating is identical to that of the 316L SS in seawater and a 1 M HCl solution, but much higher corrosion-wear resistance was observed in seawater [38]. In this work, an Fe-based AA (FeCrNiMoCSiB) acts as the target material for R. F. magnetron sputtering on 316L SS to upgrade the corrosion resistance of 316L components.…”

“…In this work, an Fe-based AA (FeCrNiMoCSiB) acts as the target material for R. F. magnetron sputtering on 316L SS to upgrade the corrosion resistance of 316L components. The corrosion characteristics of the amorphous film were tested in a 1 M HCl solution with potentiodynamic polarization tests, and the results were contrasted with those of the HVOF coating [38] and 316L [38], IN 600, and C276 alloys. The corroded features of distinct specimens were inspected using a scanning electron microscope (SEM).…”