Erosion behavior of CrN, CrAlN and CrAlN/CrN multilayer coatings deposited on Ti6Al4V

CrN, CrAlN, CrAlN/CrN multilayer coatings were deposited on Ti6Al4V substrates with Multi-arc Ion Plating technique. Hardness and elastic modulus of the nitride coatings were characterized with nano-indentation. In addition, micro-cantilever test was also utilized to measure fracture toughness . Erosion performance of the nitride coatings were also tested with gas-solid erosion test. Moreover, the erosion performance of the tested coatings was analyzed. The interface in the multilayer coating could effectively hind the propagation of the crack increasing erosion resistance of the coating. Erosion resistance of coatings was positively related to hardness and fracture toughness. The CrAlN/CrN multilayer coating with the advantages of high hardness and high fracture toughness, showed the best erosion resistance. • Fracture toughness of the thin nitride coatings was precisely measured with a microcantilever technology. • A simplified model was built to corelated the mechanical properties with erosion performance of the nitride coating. • Fracture toughness instead of hardness plays a more important role on determining erosion performance of the coatings.