Experimental and numerical wear studies of porous Reactive Plasma Sprayed Ti-6Al-4V/TiN composite coating

Abstract : The influence of porosity on the wear behaviour of a reactive plasma spray Ti-6Al-4V/TiN coating is investigated through a comparison between experimental results and numerical simulations by finite elements. Samples have been coated using optimized plasma spray conditions and then tested in linear reciprocating sliding against a Ti-6Al-4V ball under different normal loads and number of cycles. Wear tracks were investigated using a combination of scanning electron microscopy, wavelength dispersive spectroscopy and profilometry to assess friction and wear mechanisms. Finite element analysis of the wear problem has been tackled with an iterative 2D model using remeshing to simulate wear and including some of the microstructural features of the coating such as the actual porosity shape and size distribution. Finite element simulations are able to reproduce the wear kinetics observed experimentally. In addition both experimental and numerical analyses reveal that pores within the coating layer may represent weak points for the wear resistance.