Influence of spray pattern on residual stresses and coating properties of arc-sprayed aluminum bronzes sprayed with different gas mixtures

Previous own works showed the negative effects of air as pressurizing gas regarding the cavitation erosion resistance of arc-sprayed aluminum bronze coatings due to oxidation and tensile residual stresses. Furthermore, coatings sprayed with a mixture of nitrogen and hydrogen revealed superior coating qualities. A meander-shaped spray pattern was used in the aforementioned studies. However, other publications reveal, that a spiral-shaped spray pattern positively influences heat transfer during the spray process and thus also coating properties. Hence, the alloys CuAl9Ni5Fe4Mn and CuMn13Al8Fe3Ni2 were arc-sprayed with a spiral-shaped pattern in this work, using both pressurized air and a mixture of nitrogen and hydrogen. Process temperatures were recorded by thermographic imaging and residual stresses were measured by modified hole-drilling method using ESPI. Moreover, analyses of the cavitation erosion behavior and other properties were carried out. The results of this study are compared to the corresponding previous works with a meander-shaped spray pattern.