Friction and wear properties of Mo coatings on cast-iron substrates

In order to protect machining parts against wear and corrosion in automotive, aerospace, pulp and paper industries, they are coated with Mo-based materials. For these specific applications, Mo coatings were fabricated on cast-iron substrates using an atmospheric plasma-spray system and their friction and wear behavior were evaluated. The Mo coatings were subjected to sliding wear against AISI 303 counter bodies under dry and acid environments. A pin-on-plate type of apparatus was used with normal loads of 49, 89 and 129 N, and sliding speed of 1 Hz. In the steady state, it was demonstrated that the Mo-coated samples under dry conditions had slightly higher wear resistance than under acid conditions tested under a load of 129 N. Several wear failure mechanisms, such as local plastic deformation, cracks, pits, debris, grooves, scratches and tracks, were identified after the tests.