Enhanced corrosion resistance by engineering crystallography on metals

Area of Science:

• Materials Science
• Corrosion Engineering
• Electrochemistry

Background:

• Passive films on metals provide corrosion resistance but degrade over time.
• Localized corrosion, particularly chloride-induced attack, remains a significant challenge.
• Existing methods for enhancing metal durability are limited.

Purpose of the Study:

• To investigate the effect of engineered crystallographic configurations on metal corrosion resistance.
• To explore a novel pretreatment strategy for improving the long-term service life of metals.
• To enhance the performance of passive films against degradation and localized attack.

Main Methods:

• Engineered crystallographic configurations on metal matrices adjacent to passive films.
• Corrosion resistance testing of FeCr15Ni15 single crystal in sulfuric acid.
• Anodic polarization under transpassivation potential to modify metal matrices.
• Application of the transpassivation strategy to commercial stainless steels.

Main Results:

• Engineered FeCr15Ni15 single crystal showed enhanced corrosion resistance, with activation time two orders of magnitude longer than non-engineered counterparts.
• Engineering crystallography reduced passive current density and shifted pitting potential to more noble values.
• {111}-terminated configurations formed underneath transpassive films were identified as key to improved corrosion resistance.
• The transpassivation strategy successfully modified both grain interior and grain boundaries in commercial stainless steels.

Conclusions:

• Engineered crystallographic configurations offer a significant enhancement in metal corrosion resistance.
• The transpassivation strategy provides a viable method for improving the durability of metals and alloys.
• This approach has technological implications for anti-corrosion engineering pretreatment processes.