No abstract

The objective of this study is to assess the wear resistance, hardness, and porosity of HVOF-sprayed Cr3C2-25NiCr coatings applied using different oxygen and C3H8 flow rates. In the experiments, six coating samples were prepared and subjected to various tests. The sample deposited with the highest oxygen flow rate and lowest fuel-oxygen ratio exhibited the lowest porosity and highest microhardness. In general, the higher the surface hardness, the better the erosion and cavitation wear resistance. The most intense wear occurred during the erosion test conducted with an impingement angle of 60°.

This study investigates the synergistic effects of cavitation and corrosion on Cr3C2-25NiCr coatings with different levels of porosity. The coatings are deposited by HVOF spraying and evaluated based on SEM analysis, Vickers microhardness, potentiodynamic polarization measurements, and cavitation erosion tests in various environments under ultrasonic vibration. The results show that higher porosity reduces both cavitation and corrosion resistance, as expected. However, the samples did not show significant alteration of their cavitation properties in NaCl, probably because of the high corrosion resistance of the different phases in the coating. The influence of HVOF fuel-oxygen ratio and total gas flow on coating porosity, as well as phase morphology, is also discussed.