This study investigates the electrochemical corrosion behavior of phosphor bronze (Cu-Sn-P) alloy fabricated by wire-arc additive manufacturing (WAAM) compared to conventionally as-cast material. The study examined three conditions: as-cast, as-built WAAM, and heat-treated (HT) WAAM alloys. Microstructural characterization showed that the as-cast alloy exhibited heterogeneous dendritic structures with interdendritic regions, while the as-built WAAM sample displayed predominantly columnar grain structure. Heat treatment produced a more equiaxed, homogeneous microstructure and notably altered grain-boundary characteristics. Electrochemical corrosion tests in 3.5 wt.% NaCl solution using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), and cyclic potentiodynamic polarization (CPP) techniques. Results show that the HT alloy exhibits the lowest corrosion current density and significantly higher impedance during long-term immersion, while the as-cast condition showed more severe degradation. X-ray photoelectron spectroscopy (XPS) showed that the HT condition has a higher presence of Cu+ and Sn oxidized species, suggesting that corrosion behavior is influenced by alloy chemistry, microstructural heterogeneity, and the composition and stability of the surface corrosion-product layer. These findings underscore the potential of post-printing heat treatment to significantly enhance the corrosion resistance of WAAM-fabricated Cu-Sn-P alloys for marine applications.
The Akbari–Ganji method (AGM) is applied to two electrochemical problems that are regarded as typical for the method as reported by others: an enzyme system, and the catalytic EC’ mechanism. The AGM lends itself to systems that attain a steady state, described by linear or nonlinear ordinary differential equations in electrochemistry, and most often involving a diffusion space confined in a thin layer. It is found that the method can, for some parameter sets, produce results with reasonable accuracy (compared with measurement errors) but in general can be quite grossly inaccurate. The method is compared with least squares fits of the model equations used by the AGM to accurate concentration profiles obtained by simulation, and to the simulated profiles themselves.
