| 摘要 |
1,244,723. Electrolytic etching and anodizing of aluminium. HOWSON-ALGRAPHY Ltd. Nov. 11, 1968 [Nov. 15, 1967] , No. 52084/67. Heading C7B. [Also in Division G2] Aluminium or aluminium alloy sheets are electrolytically anodized using an aqueous solution of phosphoric acid as the electrolyte. Preferably a 5 to 40% v/v aqueous solution of orthophosphoric acid of specific gravity 1À75 is used at a temperature of 15 to 40‹C. for a time of 2 to 20 minutes using a current density of 0À5 to 2À0 amperes per square decimetre. The anodizing may be effected by direct or alternating current. The anodized sheet is coated with a light, sensitive material and used as a presensitized printing plate (see Division G2). Before anodizing, the sheet may be electrolytically roughened using a 0À5% w/v of hydrochloric acid with a current density of 5À0 amps per decimetre at 30‹ C. for 6 minutes using alternating current. |
