Abstract
Power Take Off steel rods are key components in wave energy. Their surfaces are exposed to among others, marine corrosion, marine biofouling, and mechanical wear. Protective coatings are sought for, and test and validation protocol for these coatings are needed. In this study metallic matrix coatings applied by laser cladding, have been tested. Accelerated testing and field methods have been employed. The goal is to use these coatings as study case for evaluation of methods itself for corrosion and wear resistance validation. The methods and preliminary results are presented and discussed. In particular: a) field test of a biofouling control strategy using mechanical scraping at different intervals; b) continuous salt spray test in three different media (conventional NaCl; artificial seawater; and natural seawater); c) cyclic potentiodynamic polarization measurement (ASTMG61) for ranking of nickel- and cobalt-based coatings and study susceptibility to localized corrosion; d) Critical crevice temperature test for nickel-based alloys (ASTMG48-D); d) Multi-degradation testing where synergy effects from wear and corrosion are considered (only discussed). The goal is to evaluate methods and experimental design to both reduce uncertainty, assist in material selection, and finally provide a pathway for final validation of PTO coatings toward a third-body certification.
