Structural and phase transformations on spark-laser coatings under fretting corrosion in air

The structure and phase transformations on the surface of a ZrB2-based combined laser–spark coating on titanium alloy are studied. The transformations are induced by triboprocesses under fretting corrosion in air. It is shown that the surface transformations result from a combination of three mechanisms: plastic deformation (surface texturing, fatigue, crack formation, brittle fracture); oxygen diffusion from the environment, chemical reactions of tribooxidation, diffusion of substrate elements (Al) toward the wear surface; and removal of particles from the surface. Two-phase nanostructured eutectic is found on the wear surface of the combined coating.