| Popis: |
The initial optical performance of silvered polymer mirrors exceeds the long-range goals for heliostat applications. Durability studies of silvered polymer mirrors use accelerated weathering devices and outdoor exposures. Continuing tests of outdoor exposures show that silvered polymer mirrors can maintain specular reflectances greater than 90% into an acceptance angle of 4 mrad for over 1 year. Materials placed in tests earlier, while the initial optical performance was still being improved, show that silver corrosion is resisted for at least 3 years and that the reflectance can be maintained at a specularity of at least 12 mrad. The polymer films do not resist abrasion as well as glass; however, hard-coats applied as a top-coat to the polymer significantly improve abrasion resistance. Ongoing durability studies of the hard-coated mirrors show that optical performance is maintained outdoors for at least 13 months. |
