Improving tribological performance of CrN coatings in seawater by structure design

Four CrN coatings were deposited on 316L stainless steel by multi-arc ion plating. The tribological behaviors of the CrN coatings were investigated by ball-on-disk tribometer in seawater. The microstructure and wear track were investigated by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and profilometer. The result shows delamination is critical to wear failure of CrN coatings in seawater and micro-cracks play an important role in the evolution of delamination. The most effective approach to eliminate the delamination is fabricating a proper multilayer structure, which could limit crack propagation only to the layer. A comprehensive wear model is established.