Magnetic disk and manufacturing method thereof
AssigneeWD Media (Singapore) Pte. Ltd.
InventorMasafumi Ishiyama
Life of this patent
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Abstract
In a magnetic disk having a magnetic layer, a protection layer, and a lubrication layer formed on a substrate in this order, a surface free energy γS of a surface of the magnetic disk derived by an extended Fowkes equation is greater than 0 and no greater than 24 mN/m. γSd (dispersion force component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 17 mN/m, γSp (dipole component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 1 mN/m, and γSh (hydrogen bonding force component of surface free energy) forming the surface free energy γS is greater than 0 and no greater than 6 mN/m.
Claims11
A manufacturing method of a magnetic disk having a magnetic layer, a protection layer, and a lubrication layer formed on a substrate in this order, comprising the steps of:
- forming said lubrication layer as a film of a perfluoropolyether compound having a flexible main chain portion containing fluorine and polar groups at ends of the main chain, the polar groups comprising first polar groups within said lubrication layer, having unexposed ends and being oriented towards said protection layer, and second polar groups that are exposed on a surface of said lubrication layer;
- and
- immediately after forming said lubrication layer, treating a surface of said magnetic disk by the use of a composition containing hydrofluoroether after formation of said lubrication layer such that a film of hydrofluoroether is formed on the surface of said magnetic disk such that the second polar groups have ends that are bonded to ether bond groups, due to contact by the hydrofluoroether with the surface of the lubrication layer to cover and inactivate the exposed polar groups.
Dependencies are inferred from the claim text.