| 摘要 |
A ferromagnetic layer having high information density capabilities is deposited on a flexible substrate in a thin, continuous, uniform and coherent manner utilizing a process which involves coating the substrate with a smooth layer of gold and a copolymer of vinylidine chloride and acrylonitrile, chemically depositing a layer of copper thereover and electrodepositing the ferromagnetic layer of cobalt no greater than 20 microinches, on top of the copper. A chemical plating bath of copper formate is used to plate the copper while the cobalt is deposited in the form of hexagonal crystals from a bath of cobalt chloride buffered with a low molecular weight carboxylic acid in a pH range of between about 3.6 and 5.8. The cobalt layer possesses a nominal coercivity within the range 200-500 oersteds which, upon exposure to a 60 cycle per second alternating current field having a strength of 1000 oersteds, exhibits a coercivity tolerance not greater than about 40 per cent of the nominal coercivity. This results in an extremely rapid switching time, thereby permitting theretofore unattainable high bit density capabilities.
|
