Corrosion resistance of PPTA Ni-based hardfacing layers

In this study, the corrosion resistance of four different hardfacing layers in a 3.5% NaCl solution was tested. Using 316L steel as a reference material, NiCrBSi, NiCrBSi + 35 wt% WC, and NiCrCuMo were deposited onto a structural steel S235JR substrate using the plasma powder transferred arc technology and prepared samples in a disc form for testing. The purpose of this investigation was to propose an alternative material to the commonly known anti-corrosion protection product of 316L steel simultaneously with better wear resistance. Its corrosion damage mechanism was assessed based on electrochemical examination and is related to changes in the microstructure of the sample surface investigated by using a potentiostat and a scanning electron microscope. Polarization tests were carried out, which confirmed that all proposed overlayers provide effective anti-corrosion protection. For all samples, the corrosion current density did not exceed 0.3 µA/cm2, and the corrosion potential was not less than −290.9 mV, which were considered positive results.