Corrosion behaviour of copper in LiBr solutions – surface examination

Abstract

Optical microscope (O.M) and scanning electron microscope (SEM) equipped with energy dispersive X‐ray (EDX) were used to follow the changes that occurred on the surfaces of copper after treated electrochemically in concentrated solutions of LiBr (up to 9 M). Results showed the existence of protective film of CuO and Cu(OH)2 which are recorded during the passive film formation in 5 × 10–1 M LiBr at 200 mV. At 1 M LiBr and during the partial passive region (600 mV) a porous film of Cu2O with a small ratio of CuOH and Cu(OH)2 were detected which confirmed the higher current density recorded. On the other hand and at the same concentration (1 M LiBr at 1000 mV), surface examination confirmed the detection of CuBr2 with small ratio of CuO which explain the deleterious effect of bromide and the autocatalytic dissolution of Cu at this higher potential. At higher concentrations from 4 to 9 M, the film formed is non homogeneous with a more porous structure which is mainly CuBr and some area of the film suffered from cracking. This proves the general dissolution through the complexing formation of soluble CuBr2–.

Inhibitive effect of benzotriazole on the corrosion and corrosion fatigue of α‐Al bronze alloy in LiBr solution

“…On the other hand, Deslouis et al reported the formation of Cu 2 O as the main constituent of corrosion product layer when copper corroded in aerated medium. El Meleigy et al confirmed the formation of CuO, Cu 2 O, and Cu(OH) 2 by EDX analysis on Cu metal surfaces when immersed in LiBr solution. The results confirmed by this group were in harmony with the result of Pehkonen et al…”

“…Since the CuBr is a porous film, the formation of Cu 2 O is possible inside the pores of CuBr according to the following reactions: …”

“…Since the CuBr is a porous film, [18,[43][44][45][46][47][48][49] the formation of Cu 2 O is possible inside the pores of CuBr according to the following reactions:…”

“…Different kinds of materials are used to construct tubing, shells or reservoirs in absorptioncooling machine systems. Intensive studies on these materials included for example, ferrous materials such as carbon steel, mild steel, [1][2][3] stainless steel, [4][5][6][7][8] and non-ferrous materials including titanium, [9][10][11] nickel, [12][13][14] nickel alloys, [15] and copper and copper-based alloys such as copper, [16][17][18][19][20] αbrass, [21] , Cu-Zn alloys, [22,23] copper-phosphorus-silver brazing alloys, [24] and Cu-Ni alloy. [25][26][27] Since copper and copper based-alloys have properties such as good resistance to corrosion, high thermal conductivity, and good mechanical workability, they represent excellent choice as competitive materials to be used in LiBr/H 2 O system for pipes and tubes as heat exchangers, and copper alloys are used for condenser materials or for storage vessel for absorber solution (LiBr/H 2 O).…”

The Electrochemical Behaviour of 70-30 Cu-Ni Alloy in LiBr Solutions

“…They are used in the construction of heat exchangers condenser in lithium bromide (LiBr) absorption machines. LiBr heavy brain is widely used as absorbents for almost all type of heating and refrigerating absorption systems (1)(2)(3)(4)(5)(6)(7)(8) .…”