Advanced Nodular Thin Dense Chromium Coating: Superior Corrosion Resistance

Area of Science:

• Materials Science
• Corrosion Engineering
• Surface Engineering

Background:

• Chromium-based functional coatings (CFCs) offer excellent wear and corrosion resistance but can degrade in aggressive conditions.
• Existing CFCs face limitations in highly corrosive environments despite microstructural improvements.

Purpose of the Study:

• To characterize the corrosion resistance of advanced CFCs, specifically a 5 μm thin dense chromium (TDC) coating.
• To investigate the microstructural features contributing to the enhanced corrosion performance of TDCs.

Main Methods:

• Fabrication and characterization of a 5 μm TDC coating.
• Electrochemical testing in aqueous NaCl electrolyte to assess corrosion resistance.
• Microstructural analysis of the TDC coating and its oxide layer.

Main Results:

• TDC coatings exhibit a uniform nodular microstructure with near-nanocrystalline grains (227 ± 75 nm).
• The coating promotes rapid formation of a stable, dense bilayer oxide, enhancing electrochemical nobility.
• Significantly low corrosion susceptibility was observed, with impeded charge/mass transport and sustained high polarization resistance.

Conclusions:

• The unique microstructure of TDC coatings provides exceptional corrosion resistance in aggressive environments.
• These findings are crucial for designing CFCs with improved durability for extreme conditions.
• The study highlights the potential of TDCs for applications requiring robust anti-corrosion performance.