Microstructural evolution and tribocorrosion performance of novel laser clad ti-ni-zro₂ composite coatings in 3.5% nacl solution

The triboelectrochemical properties of TiNi and TiNi doped with ZrO₂ laser clad coatings onto Ti6Al4V substrates have been investigated in 3.5% NaCl using potentiodynamic polarisation techniques. Laser cladding was achieved using a 2 kW Rofin Sinar continuous wave ytterbium laser system (YLS) at a scan speed of 0.0067 m/s. Microstructural analyses of the coatings revealed a strong metallurgical bond at the coatings-substrate interface with the absence of pores and cracks. There was a significant increase in surface microindentation hardness values of the cladded layers. Addition of ZrO₂ improved the tribocorrosion property of the composite coatings. Ti-Ni-5ZrO₂ had the lowest corrosion current density whilst TiNi10ZrO₂ had the lowest tribocorrosion current density in investigated electrolyte.