Tribocorrosion behavior of bare and nanocoated foils used on high-speed air-foil bearings

Irrespective of applying lubricants between high-speed machinery’s shafts and air-foil bearings (AFBs), wear and friction remain troublesome. Hence, the present study sought novel bare foil and equivalent nanocomposites to form a coating system that could mitigatly lower frictional wear between high-speed machinery’s shafts and AFBs. Bare and coated foils were supplied on rectengular dimensions of 15 × 15 × 5 mm³. Mechanical properties were characterized by Instron 3384 testing machine. Universal Tribometer s/n: RTEC2441, USA, was utilized for tribological measurements at room temperature. Surface morphologies were examined by scanning electron microscopy (SEM). Higher hardness and young modulus values were recorded from coated foils. On the other hand, specific wear rates were relatively low from coated foils. Furthermore, abrasive wear index was higher from the F2 coated foil. Friction coeffients were also lower from the coated foils under all engaged tribological conditions. Highly ruptured SEM morphologies were noticed from the bare foil. Nonetheless, mild and negligible aggressions were discovered from the surfaces of nanocoated foils.