| 摘要 |
990,453. Coating with metals. INTERNATIONAL BUSINESS MACHINES CORPORATION. Dec. 24, 1963 [Dec. 28, 1962], No. 51010/63. Drawings to Specification. Heading C7F. The surface of an aluminium metal or alloy substrate is prepared for deposition thereon of a smooth, continuous, homogeneous coating, particularly for electrodepositing a Co-Ni alloy coating in making a magnetizable record disc or drum, by providing a first smooth, malleable, adherent metallic film on the substrate surface by immersing it in a bath containing the metal(s), e.g. copper or its alloys or zinc, for the film, preferably an electroless deposition bath comprising a copper-stannate solution, levelling the film by polishing, e.g. lapping to provide the film with a smoothness of at least one microinch arithmetic average, and again immersing the substrate in the bath to superpose a second film on the first. After levelling, the substrate may again be immersed to superpose a third film. Prior to the first immersion, the substrate surface may be lap-finished to a smoothness of 7-9 microinches arithmetic average and then activated with warm nitric acid solution. An example of an electroless deposition bath contains in ounces per gallon 0À27 NaOH, 3À7 NaCN, 2À68 CuCN and 5À47 Na 2 SnO 3 . |
