On the Preparation of Hard Oxide Films with Precisely Controlled Thickness on Evaporated Aluminum Mirrors*

摘要: By increasing the thickness of natural oxide film on evaporated aluminum mirrors, a much better surface protection can be achieved. Heat treatment in air is not practical for producing protective coatings because temperature required more than 400°C and films formed at this are rough. Oxide with precisely controlled produced mirrors by anodic oxidation electrolytes such as ammonium tartrate. The layer given time increases linearly applied voltage 13.0 A-units/volt 2 minutes anodizing time. current efficiency process tartrate neighborhood 80 percent. 1.38 times thicker that replaced. amorphous free pores. They exhibit no noticeable absorption ultraviolet, visible, infra-red. Their refractive index between λ = 3000A 6000A varies from 1.67 to 1.62. Anodized show excellent abrasion resistance. To obtain highest reflectivity visible must performed 120 volts minutes. uniform opaque suitable preparation investigation reflection type interference filters. pure determined complete oxidation.