Erosion performance, corrosion characteristics and hydrophobicity of nanolayered and multilayered metal nitride coatings
By Yang, Q.; Zhao, L. R.; Patnaik, P.
Published in Surface and Coatings Technology
2019
Abstract
Nanolayered CrTiN and CrAlTiN and multilayered CrAlTiN-CrN and CrAlTiN-AlTiN coatings were deposited on 17-4PH stainless steel substrate by cathodic arc evaporation technique. All the coatings, nanolayered CrAlTiN and multilayered CrAlTiN-AlTiN coatings in particular, demonstrated higher resistance to solid particle erosion at both low and high impingement angles, when compared to bare 17-4PH substrate and monolithic CrN coating. The mass erosion rates of the CrAlTiN coating were less than 1/3 and 1/7 of the erosion rates of the CrN coating at 30° and 90°, respectively. The enhanced erosion performance was attributed to the increased hardness of the coatings. Potentiodynamic polarization tests in 3.5% NaCl aqueous solution indicated that these coatings had higher corrosion potentials, higher pitting potentials and much wider passive ranges with comparable or lower current densities, when compared to bare 17-4PH. Water contact angle measurements revealed hydrophobic characteristics of these coatings after being exposed to ambient air.