Cavitation erosion resistance of a-C:H coatings produced by PECVD on stainless steel and NiTi substrates

The resistance against cavitation erosion of hydrogenated a-C:H coated materials coated by PECVD process has been evaluated. Coatings of thicknesses between 50 and 300 nm were deposited on a pseudoelastic NiTi and two stainless steel substrates and were tested by vibratory cavitation. The results show that the incubation periods of the tested coatings deposited on steel substrates were differently modified as the coating thickness was increased depending on the type of steel substrate. On the other hand, a-C:H coatings below a critical thickness deposited on pseudoelastic NiTi exhibit an excellent resistance against cavitation erosion. The outstanding results observed in a-C:H coatings deposited on NiTi are attributed to the coating capability of copying the reversible deformation that takes place in the metallic substrate combined with a strong adhesive connection. Based on the above results, a promising application potential of a-C:H on pseudoelastic shape memory substrates is expected.