Effect of oxygen/fuel ratio on the microstructure and properties of HVOF-sprayed Al59Cu25.5Fe12.5B3 quasicrystalline coatings

Al-Cu-Fe quasicrystalline coatings were prepared using high-velocity oxygen-fuel spray technique. The influence of the O2/Fuel (O/F) ratio on the microstructure and porosity level of the coatings was investigated by scanning electron microscopy, X-ray diffraction, and Vickers microhardness measurements. The coating is predominantly (almost ~100%) composed of quasicrystalline phase after a supplementary heat treatment at 700 °C for 5 min. The results indicate that the microstructure and properties of the coatings are sensitive to the O2/Fuel ratio. A coating with the highest hardness value combined with the lowest porosity is attainable for O/F ratio slightly below 1.1, i.e. the theoretical value for complete combustion of the kerosene fuel.