Magnetic recording medium having a lubricant film coated on optimum conditions and method of evaluating the lubricant film
AssigneeHoya Corporation
InventorKen-Ichi Nishimori
Life of this patent
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Abstract
In a magnetic recording medium including a nonmagnetic substrate on which a magnetic layer, a protection film, and a lubricant film are successively stacked, the lubricant film is formed by quantitatively controlling an amount of a lubricant in consideration of a surface coverage ratio of the lubricant film relative to the protection film and an average thickness of the lubricant film. Preferably, the surface coverage ratio is selected between 0.55 and 0.985 while the average thickness is not smaller than 0.4 time an attenuation length of a photoelectron which is emitted from a predetermined element and which is attenuated in the lubricant film. To this end, an x-ray photoelectron spectroscopy is used to evaluate the lubricant film.
Claims7
A method of evaluating a magnetic recording medium which comprises a protection layer and a lubricant layer formed by lubricant polymer of PFPE on said protection layer, comprising the steps of:
- measuring a coverage ratio .beta. of covering the protection layer with the lubricant layer, by using x-ray photoelectron spectroscopy;
- measuring an average thickness t.sub.c of the lubricant layer by using x-ray photoelectron spectroscopy, the average thickness t.sub.c being specified by an attenuation length .lambda..sub.LFi of a photoelectron emitted from a specific element i included in the lubricant layer;
- and
- judging lubricity of the lubricant layer to be excellent when the coverage ratio .beta. and the average thickness t.sub.c fall within a predetermined range and at a value not smaller than 0.4 .lambda..sub.LFi, respectively.
Dependencies are inferred from the claim text.