Influence of HVOF Process Parameters on Properties of Oxide Dispersion Strengthened MCrAlY Coatings

High velocity oxy-fuel (HVOF) spraying is a conventional process for deposition of MCrAlY. Properties of HVOF coatings strongly depend on spraying parameters. HVOF process parameters of  CoNiCrAlY + 10%Ytria Stabilized Zirconia composite coatings on Inconel 617 substrate with respect to roughness, micro-hardness, deposition efficiency, porosity and fracture toughness were investigated using a Taguchi designs of experiments. The experiments were conducted using a Taguchi fractional-factorial (L8) design parametric study. Four selected important spraying parameters (oxygen flow rate, fuel flow rate, powder feed rate and spray distance) were considered in their upper, moderate and lower levels in order to display the range of processing conditions and their effect on the coating quality. For characterization of coatings, scanning electron microscopy, X-ray diffraction, Optical microscopy, image analysis and micro-hardness measurements were used. The results showed that the optimum HVOF coatings can be produced by employing the Taguchi designs of experiments.