Effect of Porosity on the Corrosion Behavior of FeCoNiMnCr<i>_x</i> Porous High-Entropy Alloy in 3.5 Wt.% NaCl Solution

Abstract

The effects of different Cr contents on the corrosion resistance of FeCoNiMnCrx (x = 0.5;1;1.5) porous high-entropy alloys (HEAs) in 3.5 wt.% NaCl solution on corrosion resistance was investigated. With the increase in Cr content, the total porosity and permeability of the porous HEA increased. The increase in porosity improves the interconnectivity between the pores and enhances the contact area with the corrosion solution. The pore-making mechanism is mainly a powder compaction, and Kirkendall holes are caused by different elements due to different diffusion rates. With the increase in Cr content, the icorr increases, and the Ecorr decreases in the porous HEAs of FeCoNiMnCrx (x = 0.5;1;1.5). The corrosion resistance of FeCoNiMnCrx (x = 0.5;1;1.5) porous HEAs decreases with the increase in the Cr element. With the increase in Cr content, the weight gain rate of FeCoNiMnCrx porous HEA increases gradually after immersion for 168 h, and the average pore size and permeability of the sample decrease gradually. The corrosion resistance of FeCoNiMnCrx porous HEA decreases with increasing Cr content.

Keywords

• porous high-entropy alloy
• corrosion resistance
• Cr element content
• immersion corrosion