Surface and Electrochemical Performance Variations of 2205 Duplex Stainless Steel in Multistep Surface Processing

Area of Science:

• Materials Science
• Corrosion Engineering

Background:

• 2205 duplex stainless steel is widely used in corrosive environments.
• Surface properties significantly influence the corrosion resistance of stainless steels.

Purpose of the Study:

• To investigate the effect of different surface processing techniques on the corrosion resistance of 2205 duplex stainless steel.
• To correlate surface characteristics with electrochemical performance.

Main Methods:

• Surface treatments: mechanical grinding (S_grd), water-sandpaper sanding (S_wap), and mechanical polishing (S_pol).
• Characterization techniques: X-ray Diffraction (XRD), Atomic Force Microscopy (AFM), X-ray Photoelectron Spectroscopy (XPS).
• Electrochemical tests to evaluate corrosion resistance.

Main Results:

• Mechanical grinding (S_grd) resulted in the lowest corrosion current due to residual compressive stress and low donor density.
• However, grinding induced lattice defects and Cr(III) hydroxide, weakening passive film stability.
• Sanding (S_wap) and polishing (S_pol) reduced residual stress, inhibited selective oxidation, and improved passive layer homogeneity.
• Lower surface roughness in S_wap and S_pol enhanced pitting resistance and overall corrosion protection.

Conclusions:

• Surface processing significantly impacts the corrosion behavior of 2205 duplex stainless steel.
• While grinding offers initial benefits, sanding and polishing provide superior long-term corrosion resistance through improved passive film quality.
• Optimizing surface roughness and minimizing defects are crucial for enhancing the durability of stainless steel in corrosive applications.