Using surface plasmon resonances to test the durability of silver-copper films

Area of Science:

• Materials Science
• Corrosion Science
• Surface Chemistry

Background:

• Silver exhibits excellent optical reflectivity but suffers from poor durability due to corrosion.
• Developing protective coatings is crucial for expanding silver's applications.
• Surface plasmon resonance (SPR) offers a sensitive technique for corrosion monitoring.

Purpose of the Study:

• To investigate the effectiveness of a thin copper layer in providing cathodic protection to silver.
• To assess the corrosion resistance of silver and silver-copper films under various environmental conditions.
• To utilize SPR for sensitive detection and evaluation of corrosion processes.

Main Methods:

• Fabrication of thin copper films (approx. 1 nm) over silver substrates.
• Exposure of silver and silver-copper films to controlled environments: air, 94% relative humidity, water, and hydrogen sulfide.
• Monitoring corrosion using surface plasmon resonance (SPR) spectroscopy.

Main Results:

• The copper flashing significantly improved the corrosion resistance of silver films.
• SPR measurements showed distinct differences in corrosion behavior between bare silver and silver-copper films.
• The protective effect of the copper layer was evident under all tested corrosive conditions.

Conclusions:

• A 1 nm copper layer provides effective cathodic protection for silver, enhancing its durability.
• SPR is a highly sensitive and valuable tool for studying silver corrosion and evaluating protective coatings.
• This technique holds promise for developing more robust silver-based materials for optical and other applications.