This study compares the erosion behavior of TiN/CrN and CrN/TiN nanostructured multilayer coatings deposited on 410 stainless steel using the physical vapor deposition method and cathodic arc evaporation (CAE-PVD). In the deposition process, a middle layer consisting of Cr and CrN was applied to the substrate, then nanolayers of TiN and CrN were applied alternately, and finally the upper layer of CrN or TiN was applied. In both cases, half of the coatings were polished and the rest remained unpolished. The nanoindentation test results showed that the hardness, Young's modulus, H/E, and H3/E2 at coating with TiN upper layer are 5.57, 1.42, 3.86, and 85.39 times those of the substrate and at coating with CrN upper layer are 4.04, 1.13, 3.53 and 51.68 times of substrate. The results of the erosion test also showed that the amount of lost mass in the smooth TiN upper layer, rough TiN upper layer, smooth CrN upper layer and rough CrN upper layer coatings has decreased by 73%, 65%, 67% and 64% compared to the substrate at impact angle of 30 degrees and 36%, 4%, 40% and -2% at impact angle of 90 degrees. As a result, in the smooth form, the coatings were more resistant to erosion. According to the results, increasing the H/E and H3/E2 ratio increased erosion resistance. The results of the erosion test also demonstrated that, in contrast to the erosion test, the substrate displays ductile material behavior and the coatings display brittle material behavior.
