| 摘要 |
A metal reflector is made by casting a reflector body of an aluminium alloy containing magnesium and/or silicon, polishing, degreasing and treating the body with a glow discharge under vacuum, vapour depositing a film of aluminium on the treated surface and finally treating the deposited film e.g. by anodizing to form an oxide film. The aluminium casting alloys used contain 3% magnesium, not more than 0.6% manganese and not more than 0.3% silicon; or 0.4% manganese, from 12-13.5% silicon; or 1% magnesium, from 0.2-1% manganese and 5% silicon. The casting is polished, cleaned in trichloroethane at 250-275 DEG C., treated for 10 minutes in a glow discharge and then vapour coated with a layer of aluminium 1.5 microns thick. The coating was anodized in ammonium tartrate to give an oxide layer 0.1-1 micron thick. |
