Effect of Al additions in WC-(Cr1−xAlx)N coatings on the corrosion resistance of coated AISI D2 steel in a deaerated 3.5 wt.% NaCl solution

The results of potentiodynamic polarization test showed that the WC-Cr0.48Al0.52N coating with lower porosity exhibited the lower corrosion current density. The galvanic corrosion current between the coating and the substrate showed low values. In EIS measurements, the charge transfer resistance (Rct) value of WC-Cr0.48Al0.52N coating only increased with the immersion time, when compared to the other coatings. It can be due to the corrosion products plugging the pores and increasing the pathway resistance.