Display Settings:

Format

Send to:

Choose Destination
See comment in PubMed Commons below
Appl Opt. 2006 Mar 1;45(7):1583-93.

Corrosion characterization of durable silver coatings by electrochemical impedance spectroscopy and accelerated environmental testing.

Author information

  • 1Space Materials Laboratory, The Aerospace Corporation, Mail Station M2/248, P.O. Box 92957, Los Angeles, California 90009-2957, USA. chung-tse.chu@aero.org

Abstract

Highly reflective front-surface silver mirrors are needed for many optical applications. While various protective dielectric coating schemes have been developed, the long-term durability of Ag mirrors is still of great concern in the optics community for a variety of applications under harsh environments. The corrosion protection behavior of a SiNx-coated silver-mirror coating scheme was tested with electrochemical impedance spectroscopy (EIS) and accelerated environmental testing, including humidity and salt fog tests. The EIS data obtained were fitted with different equivalent circuit models. The results suggested that the 100A thick SiNx coating produced by rf magnetron sputtering was porous and acted as a leaky capacitor on the Ag film, whereas the addition of a NiCrNx interlayer as thin as 3A between SiNx and Ag films resulted in a much denser SiNx coating with a low-frequency impedance value of 2 orders of magnitude higher than that without the interlayer. Humidity and salt fog testing of different silver coatings showed similar results. The 100A SiNx/3A-NiCrNx/Ag coating exhibited excellent corrosion resistance against the corrosive environments used in this study.

PMID:
16539267
[PubMed]
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Icon for Optical Society of America
    Loading ...
    Write to the Help Desk