Effect of Fluid Velocity and Exposure Time on Copper Corrosion in a Concentrated Lithium Bromide Solution

Abstract

A study was carried out to investigate the effect of hydrodynamic variables and exposure time on the corrosion of copper in a 4.6-M lithium bromide (LiBr) solution at room temperature using electrochemical techniques. The corrosion rate, measured in terms of the corrosion current density (i corr ), increased with the Reynolds number following a potential relation typical of processes controlled by the mass transport of the species formed in the dissolution process through the corrosion product film and the diffusion boundary layer, the effect of erosion caused by the particles of the corrosion product being negligible. In the range of the fluid velocities investigated, the corrosion potential (E corr ) shifted to more noble values, and the passivating current density decreased with the increase in fluid velocity as a result of the stabilization of the passive film formed. Over the exposure period, E corr and i corr increased sharply, reaching a maximum on the first days of exposition. After this time, E corr and i corr decreased, exhibiting slight fluctuations around a mean value.

Mass Transfer in the Electro-Dissolution of 90% Copper-10% Nickel Alloy in a Solution of Lithium Bromide

“…The end of the apparent Tafel region is associated with the formation of CuBr (Brossard, 1984b;Valero-Gómez et al, 2006). A similar pattern was seen in the work of (Pérez-Herranz et al, 2001) at a Re = 263. This behavior was attributed by (Aben & Tromans, 1995cited in Pérez-Herranz et al, 2001) to the CuBr formation, and the stationary current observed at nobler potentials was attributed to the presence of a CuBr passive film.…”

“…(Lee & Nobe, 1984, Fig 2, 4-5) claim that the anodic behavior in this region is an "apparent" Tafel behavior, since it doesn´t represent an activation controlled process. This idea is shared by other researchers, however, (Kato & Pickering, 1984;Pérez-Herranz et al, 2001) despite stating that for a slope of 60 mV/decade the anodic process is controlled by diffusion, determine the i corr by the Tafel extrapolation method (Fontana & Greene, 1978;Flitt & Schweinsberg, 2005), which is well known and often poorly implemented. Researchers often forget that the metal needs to corrode evenly, and in the corrosion potential the anodic and/or cathodic reactions must be under complete control by activation.…”

“…However, these researchers argue that the electro-dissolution of metal is controlled by a mass transport process. The value of this parameter (Pérez-Herranz et al, 2001) is in a range of 70 to 80 mV /decade, for a velocity range of 265 < Re <3,120. This range is close to slopes of 60 mV/decade, typical of a metal dissolution process controlled by diffusion of products from the metal surface to the bulk of the solution.…”

Electrochemical evaluation of patinas formed on nineteenth century bronze bells

“…Diffusion occurs through the protective passive layer [21,22]. The first semicircle reflects the charge transfer from the metal to the electrolyte, while the second one emerges due to adsorption effects and the formation and presence of a protective layer.…”

Characterization and Electrochemical Mechanism for Bromide-Containing Conductive Anodic Filament (CAF) Failure

“…In the last 25 years 20-31 the copper bromide system has attracted more interest due to its application in copper heat exchangers which use LiBr as an absorbing agent, 29 with the bulk of the studies being done in the last 10 years. 20,[25][26][27][28][29][30][31] All electrochemical studies of the copper bromide system have shown that it behaves similar to the copper chloride system. 21,23 The work by Brossard 21 as well as Aben and Troman 23 found that corrosion of copper occurred according to the following reactions: Cu þ Br À !…”