Abstract
The corrosion behavior of Ni-P deposits with the phosphorous contents of 20, 24 and 28 at.% (denoted as Ni-20P, Ni-24P, and Ni-28P, respectively) and annealed in air at different temperatures was systemically compared in a brine medium containing 3wt.% NaCl. The anticorrosive properties of these Ni-P deposits were further examined in a brine-fog test (using a 5wt.% NaCl solution) under 37°C for 24 h. In the electrochemical studies, the Ni-28P deposit showed the lowest corrosion rate when it has been annealed between 200 and 300°C. This deposit also exhibited the highest corrosion resistance in the studies of linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). In the brine-fog study, the weight loss of the Ni-P deposits was found to decrease with increasing the phosphorous content. After the brine-fog test, there was no obvious change in morphologies for all Ni-P deposits with the annealing treatment at 300°C. © 2003 Elsevier Science B.V. All rights reserved.