PRODUCTION OF MAGNETIC RECORDING MEDIUM

摘要

PURPOSE:To enable mass production of a magnetic recording medium for vertical magnetic recording with good reproducibility and to obtain the medium having high coercive force by using a high polymer base plate having high versatility by maintaining the temp. in the stage of depositing a thin ''Permalloy'' film by evaporation higher than the temp. in the stage of depositing a vertically magnetized film by evaporation. CONSTITUTION:Polyamide imide having about 10mum thickness is preliminarily subjected to a glow discharge treatment to form a thin Ni-Fe alloy film to about 0.5mum and in succession a thin Co-Cr alloy film is formed at about 0.15mum. The base plate is masked to keep the incident angle of Co-Cr within 6 deg. and said alloy is deposited by evaporation under the conditions under which vertical orientation is easy. The alloy is deposited by evaporation while the relation at which the base plate temp. in the stage of vapor deposition of Ni-Fe is higher by 55 deg.C than the base plate temp. in the stage of vapor deposition of Co-Cr is maintained. The vertical coercive force of the Co-Cr film obtd. in such a way is as shown in the figure.