As
the head fly height approaches the sub-10
nanometers, it is increasingly important
to understand the implication of disk
topography (asperity
defects, microwaviness) on
how low the slider can safely fly. It
is also critical to protect the disk
magnetic film from damage during operation.
For that matter, a thin layer (3-7 nm)
of a hard protective
overcoat, usually carbon-based,
is deposited onto the disk. This overcoat
serves as protection against corrosion
as well. A monolayer of functionalized
lubricant 0.5-2 nm thick is topically
applied on the overcoat as an added
protection against wear, and also to
lower the surface energy of the disk
against contaminant absorption. The
physics
and chemistry of this nanometer
thin layer of lubricant under extremely
high shear rate is of extreme importance
in this technological field, as demand
for robustness and reliability under
heavy customer usage becomes critical.
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