Flow influenced electrochemical corrosion of nickel aluminium bronze ? Part II. Anodic polarisation and derivation of the mixed potential

Abstract

The mixed charge and mass transfer influenced anodic current response of CA 104 nickel aluminium bronze (NAB) is presented as a function of both laminar (rotating disc electrode) and fully turbulent (rotating cylinder electrode) fluid flow. At low values of positive polarisation, the overall behaviour of the freshly polished material in filtered and artificial seawaters is closely related to that of unalloyed copper. The primary anodic reaction in this case is the selective dissolution of the copper component via a cuprous di-chloride complex anion. At large positive polarisation, the solid solution mole fraction for the production of a discrete film of protective alumina (Al 2 O 3 ) is examined as a function of Reynolds number and discussed in terms of a new mechanism for the passivation NAB in seawater. The polarisation data is used to replicate experimental Reynolds number dependent, corrosion potentials and corrosion current densities over a wide range of electrode angular velocities.

The rotating cylinder electrode for studies of corrosion engineering and protection of metals—An illustrated review

“…The [14]. After initial immersion in each of the electrolytes, it was observed that for a given angular velocity, the corrosion potential, E cor , tended to became more negative with time until a stable potential was achieved.…”

“…In a series of papers by Kear et al [12][13][14][15], oxygen reduction at NAB in aqueous chloride electrolytes was considered. The cathodic polarisation behaviour was examined in fully characterised seawaters (filtered and artificial) using the RDE and the RCE [12].…”

Effect of Multiple-Pass Friction Stir Processing Overlapping on Microstructure and Mechanical Properties of As-Cast NiAl Bronze

“…THE NiAl bronze alloy (NAB) is extensively used for propulsion and seawater handling systems [1][2][3][4][5][6] due to the high strength, good fracture toughness, and excellent erosion-corrosion resistance. [1][2][3][4]7] The as-cast NAB is characterized by coarse Widmansta¨tten a phase, nickeliron-aluminum j phases, and island martensite b¢ phase, and the transformation products and their precipitation sequence are complex.…”

Electrochemical behavior of aluminum bronze in sulfate-chloride media

“…Aluminum-bronze is widely used in heat-exchangers. The addition of aluminum to copper increases its corrosion resistance in sea water, sulphuric acid and salt solutions [5]. Alloys with aluminum content up to 8% have completely face-centered cubic (fcc) a structures and good mechanical and corrosion resistance.…”

“…For Cu-Al alloys, passivation is based on aluminum which has a greater affinity to O 2 than copper, forming Al 2 O 3 [8]. The cathodic and anodic polarization of nickel aluminum bronze was investigated in seawater [2,5]. The results indicated that, the reduction of oxygen dominates the cathodic process and is controlled by the exchange of a single electron.…”