The invention discloses a
surface coating for prolonging the fatigue life of
metal and a preparation method of the
surface coating. According to the
coating, face-centered cubic structure
layers and hexagonal
system structure
layers are alternately stacked to form a
superlattice structure, the
total thickness ranges from 1.0
micrometer to 1.5 micrometers, and a base material is
titanium alloy. The thickness of the face-centered cubic structure layer is 4-6 nm, the thickness of the hexagonal
system structure layer is 1-3 nm, the Mohs
hardness difference between the two
layers is not larger than 2, and the average grain size is 1-2 nm. According to the
coating, a stable high-
toughness interface phase is obtained through a specific
crystal structure and thickness regulation and control, and
dislocation slippage and crack propagation are effectively prevented. A magnetron
sputtering method is adopted for preparation, and the process comprises the steps of
substrate surface pretreatment, bias cleaning and alternate deposition. The
coating shows excellent anti-fatigue performance under the cyclic load condition, and the service life of the
titanium alloy component can be remarkably prolonged.