Corrosion and mechanical performance of HVOF WC-based coatings with alloyed nickel binder for use in marine hydraulic applications

Abstract

Hydraulic components used in the maritime environment suffer damage due to the effects of corrosion and marine biofouling accumulation. The application of engineered coatings can overcome these problems. This study investigated the corrosion and mechanical performance of novel high velocity oxygen fuel (HVOF) sprayed ceramic-metal composite coatings; i.e., WC-18 wt% Hastelloy C and WC-10 wt% Ni-5 wt% Cr, designed for the protection of marine hydraulic components. A conventional atmospheric plasma sprayed (APS) ceramic coating (i.e., Al2O3-40 wt% TiO2) and uncoated Monel K500 substrate were tested for benchmarking purposes. The corrosion performance of the samples was assessed using a combination of laboratory-based tests (i.e., electrochemical polarization, neutral salt spray, hot water immersion) and field exposure tests by immersion in seawater. The mechanical properties of the samples were assessed via a drop-weight impact test and the tensile adhesion test. The results showed that the HVOF coatings exhibited better corrosion resistance and mechanical performance compared to the baseline APS ceramic coating and uncoated Monel K500 substrate.