Investigation on Microstructural, Mechanical, Tribological and Corrosion Behaviour of Zk60 substrate coated with NiCr and Cr₃C₂-NiCr powder deposited by HVOF process

Abstract Due to the strength-to-weight ratio, magnesium alloys are widely used in lightweight applications. However, they are limited by their low mechanical, tribological, and corrosion properties. This study investigates the Microstructural, Mechanical, Tribological, and Corrosion Behaviour of a ZK60 substrate coated with Ni-20% Cr and Cr₃C₂-25% (Ni-20% Cr) powder deposited by the HVOF (high-velocity oxygen fuel) thermal spray process. XRD, SEM, and EDS studies reveal the coating's phase composition, surface morphology, and elemental compositions, respectively. The mechanical and tribological results indicate that Cr₃C₂-25% (Ni-20%Cr) coatings exhibit the dominant performance. The corrosion resistance test was conducted using the potentiodynamic polarisation technique. The results of coatings exhibited dense microstructures with embedded carbide particles. The Ni-20% Cr and Cr₃C₂-25% (Ni-20% Cr) coatings enhanced the resistance to corrosion for the Mg alloy, resulting in corrosion current density (Icorr) values of 0.135 µA/cm² and 0.166 µA/cm², respectively. The Icorr value confirms the effectiveness of these coatings in mitigating corrosion, whereas the Icorr value of the substrate was 14.573 µA/cm². Both coatings significantly enhanced the mechanical, tribological and corrosion behaviour of the ZK60 alloy substrate.