Evaluation of synergistic effect and failure characterization for Ni-based nanostructured coatings and 17-4PH SS under cavitation exposure in 3.5 wt % NaCl solution

The Ni/SiC nanocomposite and Ni nanocrystalline coatings were electrodeposited on a 17-4 precipitation hardening stainless steel substrate. The failure characterization of specimens as well as synergistic effect of cavitation and corrosion, and the influence of the mechanical, electrochemical, and microstructural attributions of the Ni-based nanostructured and 17-4 PH stainless steel substrate on their cavitation resistance were investigated. The surface morphology of 17-4PH stainless demonstrated the quasi-cleavage failure mechanism, and both coatings had the dimpled rupture morphology after the cavitation deterioration in both mediums. The results also represented that the synergism contribution of cavitation and corrosion was 29.5, 22.6, and 6.3% for 17-4 PH stainless steel substrate, Ni nanocrystalline, and Ni/SiC nanocomposite coatings, correspondingly. •Cavitation-corrosion synergistic effect of Ni-nanostructured coatings and17-4PHSS.•Ni/SiC nanocomposite coating and 17-4PHSS affected differently by synergistic effect.•Hardness has a more pivotal role than corrosion for providing cavitation resistance.•Ni-nanostructured coatings had dimpled rupture failure consisting of protruding rims.•17-4PHSS showed quasi-cleavage fracture morphology with dimples and cleavage facets.