Dynamic Polarization Behaviors of Equimolar CoCrFeNi High-Entropy Alloy Compared with 304 Stainless Steel in 0.5 M H[sub.2]SO[sub.4] Aerated Aqueous Solution

Three corrosion potentials and three corrosion current densities are clearly identified before the passivation for both dynamic polarization curves of equimolar CoCrFeNi high-entropy alloy (HEA) and 304 stainless steel (304SS) in 0.5 M H[sub.2]SO[sub.4] aerated aqueous solution, by decomposing anodi...

Full description

Saved in:
Bibliographic Details
Published in:Materials 2022-10, Vol.15 (19)
Main Authors: Yen, Chao-Chun, Tsai, Ting-Lun, Wu, Bo-Wei, Lo, Yu-Chieh, Tsai, Ming-Hung, Yen, Shiow-Kang
Format: Article
Language:English
Subjects:
Alloys
Crystals
Intermetallic compounds
Specialty metals industry
Steel, Stainless
Structure
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Three corrosion potentials and three corrosion current densities are clearly identified before the passivation for both dynamic polarization curves of equimolar CoCrFeNi high-entropy alloy (HEA) and 304 stainless steel (304SS) in 0.5 M H[sub.2]SO[sub.4] aerated aqueous solution, by decomposing anodic and cathodic polarization curves. The passivated current density of the former is greater than the latter, compliant with not only the constant of solubility product (k[sub.sp]) and redox equilibrium potential (Eeq) of each metal hydroxide but also the sequence of bond energy (Eb) for monolayer hydroxide on their facets derived from the first principle founded on density function theory. However, the total amount of ion releasing from HEA is less than 304SS, since the hydroxide/oxide film formed in the air of the latter containing greater amounts of Fe(Ⅱ) and Mn(Ⅱ) is less stable around corrosion potentials while they are further oxidized into more stable Fe(Ⅲ) and Mn(ⅢorⅣ) with much lower k[sub.sp], leading to the much less increasing ratios of ion releases from 0.25 to 0.6 V.
ISSN:1996-1944
1996-1944
DOI:10.3390/ma15196976