Effects of low-temperature duplex coatings on the abrasive and erosive behavior of ADI

This study utilized electroless nickel (EN) and cathodic arc evaporation (CAE) technologies, which have the well-known advantage of low processing temperature (EN = 90 °C and CAE = 230 °C), to treat the austempered ductile iron (ADI) substrate. The eligibility of applying the EN and CAE-CrTiAlN duplex coatings on ADI, along with the coating properties, such as structure, roughness, and adhesion, was evaluated and analyzed. Wear and erosive tests were also performed to further understand the effects of the coatings on the abrasive and erosive behaviors of ADI. The results show that the unique microstructure of ADI does not deteriorate after EN and CAE treatments. With regard to erosion resistance, the duplex coated specimens perform better than do the uncoated and monolithic EN or CrTiAlN coated ones. Moreover, the duplex coatings achieve a remarkable reduction in ADI's friction coefficient from 0.85 to 0.6.