Method of forming patterns on anodized aluminium surfaces

摘要

Anodising. An etched aluminium sheet may be anodized for one hour in a 15% sulphuric acid solution at 20 DEG C.and 15 amp.per square foot and sealed by immersion for one hour in boiling, deionized water. This gives a black finish to the outermost layer of an alloy containing 12% Si and a silver-grey finish to a commercially pure aluminium intermediate layer. A gold colour may be imparted to the latter by immersion in an aqueous solution containing 5 grams per litre ferric ammonium oxalate of pH 5.5 at 55 DEG C.after anodizing, but before sealing.