Optimizing Corrosion Performance of WC/a-C Nanomultilayers by Tailoring Modulation Period for PEMFC Bipolar Plate...

Area of Science:

• Materials Science
• Electrochemistry
• Corrosion Engineering

Background:

• Proton exchange membrane fuel cells (PEMFCs) require robust materials for long-term operation.
• Corrosion of metallic components in the cathode environment is a significant challenge.
• Protective coatings are essential to prevent substrate degradation.

Purpose of the Study:

• To investigate the effect of modulation period in WC/a-C nanomultilayers on corrosion behavior.
• To determine the optimal modulation period for enhanced corrosion resistance in PEMFC cathode environments.
• To understand the mechanisms of corrosion in relation to nanomultilayer structure.

Main Methods:

• Deposition of WC/a-C nanomultilayers on AISI 304 stainless steel substrates.
• Systematic variation of the modulation period during film deposition.
• Electrochemical corrosion testing in a simulated PEMFC cathode environment.
• Analysis of film microstructure and corrosion-induced changes.

Main Results:

• Increased modulation period led to expanded and densified columnar boundaries.
• Higher modulation periods facilitated ion infiltration and substrate corrosion.
• The 5.8 nm modulation period exhibited superior corrosion resistance, with higher corrosion potential and lower current density.
• Significant corrosion, cracking, and bulging were observed at an 11.5 nm modulation period.

Conclusions:

• The modulation period critically influences the protective properties of WC/a-C nanomultilayers.
• A shorter modulation period (5.8 nm) enhances corrosion resistance by improving film integrity.
• Optimizing nanomultilayer structure is crucial for durable PEMFC components.