Composite lubricant for hard disk media

A method, comprising:

• providing a disk comprising a carbon-based overcoat (COC) disposed thereon;
• and
• forming a composite lubricant on the COC, wherein the composite lubricant comprises:
• a non-phosphazene component comprising a difunctional perfluoropolyether compound terminated with first and second polar end groups, the first polar end group comprising a first number of hydroxyls and the second polar end comprising a second number of hydroxyls, greater than the first number of hydroxyls;
• and
• a phosphazene component combined with the non-phosphazene component, the phosphazene component comprising a difunctional perfluoropolyether compound terminated with a phosphazene functional group and with a third polar end group, the third polar end group comprising a third number of hydroxyls.

A magnetic recording disk, comprising:

• a base structure;
• a carbon-based overcoat (COC) disposed above the base structure;
• and
• a composite lubricant layer disposed above the COC, the composite lubricant layer comprising:
• a non-phosphazene component comprising a difunctional perfluoropolyether compound terminated with first and second polar end groups, the first polar end group comprising a first number of hydroxyls and the second polar end comprising a second number of hydroxyls, greater than the first number of hydroxyls;
• and
• a phosphazene component combined with the non-phosphazene component, the phosphazene component comprising a difunctional perfluoropolyether compound terminated with a phosphazene functional group and with a third polar end group, the third polar end group comprising a third number of hydroxyls.

The magnetic recording disk of 20, wherein the non-phosphazene component is represented by the chemical formula:

• R1—O—(CF2—CF2—O)n—(CF2—O)m—R2, wherein R1 is CH2OH—CF2—, R2 is —CF2—CH2OCH2CH(OH)CH2OH, and n and m are between 1 and 30;
• and
• wherein the phosphazene component is represented by the chemical formula:
• G—O—(CF2—CF2—O)n—(CF2—O)m—R3, wherein G is —CF2—CH2—O—P3N3—(O—C6H4—CF3)5, R3 is —CF2CH2OCH2CH(OH)CH2OH, and n and m are between 1 and 30.