Influence of Gas Pressure on the Mechanical and Tribological Properties of Cu-Al Coatings Deposited via Thermal Spray

We report the results of the influence of the acetylene and oxygen gas pressure on the wear resistance of aluminum–bronze coatings deposited on naval brass substrate by means of the thermal (flame) deposition process. The coatings were characterized by means of scanning electronic microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), X-ray diffraction (XRD), and X-ray fluorescence (XRF). The adhesion was determined with cross-hatching tests, and the mechanical response was assessed by measuring the nanohardness and by three-body and ball-on-disk abrasive wear tests. The results indicate that changes in the pressure and flow of the gas affect the morphology and the mechanical properties of the coatings, and these effects have consequences for the wear behavior of the coatings. Before the projection of the coatings, numerical simulations were carried out using Jets & Poudres software, where the collision speed of the particles was identified as the most significant factor that influences the mechanical properties and the performance of the coating. The gas pressure modified the hardness and the porosity level, which allowed improving the wear resistance.