Cavitation Resistance of TiN Nanocrystalline Coatings with Various Thickness

TiN nanocrystalline coatings of various thicknesses deposited on austenitic stainless steel, X6CrNiTi18-10, by means of the cathodic arc evaporation method were investigated in a cavitation tunnel with a slot cavitator. The estimated cavitation resistance parameters of the coatings were the incubation period and total mass loss. It was found that the incubation periods of the 4 μm and 7.8 μm-thick TiN coatings were over two and half times longer than that of the uncoated X6CrNiTi 18-10 steel and the total mass losses of these coatings were approximately half lower than of the uncoated specimen. The scanning electron microscope analysis indicated that the damage process of the TiN-4 coating originates from the micro-folding and coating fracture arises on the top of the micro-folds, whiles the TiN-8 and TiN-12 coatings were removed in the form of thin flakes. The factors mainly responsible for cavitation resistance of the TiN coatings are ability to plastic deformation of the coating and coating adhesion.