Strength and surface characterization of aluminum-coated fused silica fibers

Hermetic aluminum-coated fused silica fibers can withstand high stress levels without failure for prolonged periods of time in water-containing environments. Aluminum-coated fibers from several sources exhibit differences in strength. The aluminum and silica surfaces have been examined using SEM and AFM in order to understand this variation. Differences in the interfacial interaction between aluminum and glass and in the microstructure of the coatings were considered, but were not unequivocally identified as being responsible for the differences in strength observed for the various aluminum-coated specimens.