Microsrtructural and mechanical characterization of HVOF sprayed Ni-based alloy coating

The various engineering components works under aggressive environments include the furnace parts, sliding parts in lathe machine and exhaust manifolds. Cast iron is used in these applications and important intention of this research work is to study on enhance the useful period of life.HVOF (High Velocity Oxy-fuel) sprayed Alloy-718coatings on cast iron were analysed. Coatings were characterised by field emission scanning electron microscopy (FE-SEM), Optical microscope (OM) and X-ray diffraction for its microstructural analysis. Energy dispersive spectroscopy (EDS) of the bare and coated samples was used to confirm the elemental details of the powder and the coating. Porosity measurements were taken and showed the 1.6% for Alloy-718 coating. Microhardness investigation was conducted for the Alloy-718 coating, and it was resulted as 560±20 HV. The bare material has hardness of 225±10, and there is a substantial difference of hardness found as 2.5 times higher. The fracture toughness was found to be 4.0 MPa.m1/2.