Mechanical Properties of NiTi Plasma Spray Coating

NiTi shape-memory alloy coatings were deposited by atmospheric plasma spray (APS) on mild-steel substrates and their mechanical properties such as hardness (Vickers's microhardness), adhesion strength (ASTM C-633), and wear resistance (solid particle erosion) analyzed. The physical characteristics of the surface and interface of the as-deposited coating were investigated using scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and x-ray diffraction (XRD) analysis. Also, the as-deposited coatings were exposed to airborne particle erosion to investigate their wear behavior for different erodent impact angles. The correlations between various plasma parameters and the erosive wear resistance and mechanical properties of the coating were established. In addition, the surface morphology of the eroded surface was investigated by scanning electron microscopy to analyze the different wear mechanisms (plastic deformation, crater formation, splat boundary pile-up, and lip formation) occurring on the surface.