Effect of electroless Ni-B and Ni-W-B coatings on the corrosion-fatigue behaviour of 7075 Al alloy

Abstract

This research experimentally determines the effect of electroless Ni-B and Ni-W-B coatings on the fatigue and corrosion-fatigue life of 7075 Al alloy substrate. SEM, XRD, fracture toughness and potentiodynamic polarization tests exhibited the characteristics of the coatings. The fatigue test results revealed that easy crack initiation from the brittle coating is the main responsible for a reduction in fatigue performance of coated specimen. The Ni-B coating offered superior resistance in terms of both corrosion and corrosion fatigue compared to Ni-W-B coating. Considerable improvement was achieved in corrosion fatigue performance of Ni-B coated specimens.