title: Electroless silver as an optical coating in an operational environment.
abstract: Long-term, independent experiments show a high degradation rate and short lifetime for electroless silver as a mirror coating operating at visible wavelengths in an observatory environment. Acid formed by water vapor mixing with sulfur in volcanic dust diffuses through pinholes in the coating generated during deposition. This causes internal corrosion and delamination after only 3-4 months. In addition, a layer of silver sulfide results in tarnish, which reduces reflectance. Rates of sulfidation and internal corrosion are shown to depend on the concentration of sulfur and the exposure rate. Comparisons of performance, lifetime, and the application process are made with bare aluminum and two variations of enhanced silver.
authors.forename: D
authors.initials: D
authors.lastname: Nahrstedt
authors.forename: T
authors.initials: T
authors.lastname: Glesne
authors.forename: J
authors.initials: J
authors.lastname: McNally
authors.forename: J
authors.initials: J
authors.lastname: Kenemuth
authors.forename: B
authors.initials: B
authors.lastname: Magrath