Influence of turbulent flow on the corrosion of Al‐Zn‐Mg galvanic anode in artificial seawater media

Abstract

The effect of hydrodynamics on the corrosion of Al(14 wt%)-Zn(8 wt%)-Mg alloy in artificial seawater media at room temperature was studied in a rotating cylinder electrode (RCE) system under turbulent flow conditions. Five different rotation rates were studied: 100, 1000, 3000, 5000, and 7000 rpm. The corrosion rates were measured by electrochemical impedance spectroscopy (EIS). For the system studied, the steady-state corrosion potential increased with increase in rotation rate. The effect of increasing the rotation rate is to increase the availability of oxygen at the surface, which in turn will polarize the corrosion reaction in the more noble direction. The corrosion rate also increases with increase in RCE rotation rate. This reflects the fact that the rate of corrosion is controlled, at least in part, by the rate of mass transfer. In this case, the effect of increase in the rotation rate on the corrosion rate is to increase the interfacial concentration of the reactant (oxygen).

Corrosion behaviour and mechanism of 6082 aluminium alloy in NaCl and Na2SO4 etchants

“…An Al(OH) 3 protective film is formed by the reaction of Al 3+ ions with OH − , as follows. The reaction between Al 3+ and OH − results in an Al (OH) 3…”

“…→ This type of corrosion product (Al(OH) 3 ) is adsorbed at the surface of the sample and acts as a protective or passivation film. The protective film can effectively impede ion transfer and diffusion between the aluminium sample and the solution.…”

“…Aluminium alloys are one of the most widely used structural engineering materials. Because aluminium alloys have better corrosion resistance, weldability, formability, and a higher specific strength, they are often employed in the aerospace, transportation, navigation and architecture industries, among others. As navigation technology is developed, the ratio of aluminium alloys used in the navigation industry increases.…”

Theoretical simulation and preparation of binary and ternary combinatorial libraries by thermal PVD

“…Regarding zinc, aluminium, and magnesium as the most important metals for cathodic corrosion protection 12–14, all components are suitable for evaporation by thermal PVD.…”