Magnetic disk and manufacturing method thereof

Abstract

A magnetic disk of is provided, the magnetic disk having at least a magnetic layer, a carbon protective layer, and a lubrication layer sequentially provided on a substrate. In an embodiment, the lubrication layer a film formed by a lubricant having a perfluoropolyether compound A having a perfluoropolyether main chain in the structure and also having a hydroxyl group at the end and a compound C obtained from a reaction between a compound B expressed by: [Chemical formula 1] CF3(—O—C2F4)m-(O—CF2)n-OCF3 [m and n in the formula are natural numbers.] and aluminum oxide.

What is claimed is: 
     
         1 . A magnetic disk having at least a magnetic layer, a protective layer, and a lubrication layer sequentially provided on a substrate, characterized in that said lubrication layer is a film formed by a lubricant that contains two types of compounds having a perfluoropolyether main chain in the structure, a molecular weight distribution of the two types in total being within a range of 1 to 1.2, the two types of compounds including a compound a having a hydroxyl group at the end and a compound b having a number average molecular weight smaller than the number average molecular weight of the compound a and not more than 1500, and a content of the compound b in the two types of compounds being not more than 10%. 
     
     
         2 . The magnetic disk according to  claim 1 , wherein the number average molecular weight of said compound a is within a range of 1000 to 10000. 
     
     
         3 . A magnetic disk having at least a magnetic layer, a protective layer, and a lubrication layer sequentially provided on a substrate, characterized in that said lubrication layer is a film formed by a lubricant containing a perfluoropolyether compound a having a perfluoropolyether main chain in the structure and a hydroxyl group at the end and a compound b with the number average molecular weight not more than 1500 having a perfluoropolyether main chain in the structure and an aromatic group at both ends of the hydroxyl group and a chain-state molecule. 
     
     
         4 . The magnetic disk according to  claim 3 , wherein the number average molecular weight of said compound a contained in said lubrication layer is within a range of 1000 to 10000. 
     
     
         5 . The magnetic disk according to  claim 3 , wherein said protective layer is a carbon protective layer, which is a film formed by the plasma CVD method. 
     
     
         6 . The magnetic disk according to  claim 3 , wherein the magnetic disk is a magnetic disk mounted on a Load-Unload method magnetic disk device. 
     
     
         7 . The magnetic disk according to  claim 4 , wherein said protective layer is a carbon protective layer, which is a film formed by the plasma CVD method. 
     
     
         8 . The magnetic disk according to  claim 4 , wherein the magnetic disk is a magnetic disk mounted on a Load-Unload method magnetic disk device. 
     
     
         9 . The magnetic disk according to  claim 5 , wherein the magnetic disk is a magnetic disk mounted on a Load-Unload method magnetic disk device. 
     
     
         10 . The magnetic disk according to  claim 7 , wherein the magnetic disk is a magnetic disk mounted on a Load-Unload method magnetic disk device.