Influence of DC Current on Corrosion Behaviour of Copper–Aluminium Composite Plates

Comparative study on mechanism of DC and AC current on corrosion of copper–aluminium composites

“…EDS analysis was carried out for three typical morphologies, and the results are shown in Figure 3(g) to (i). According to the EDS results and the previous research results, 18,19 the main components of the folded corrosion products, massive accumulation corrosion products and cracking white corrosion products are Al 2 O 3 , AlO(OH) and Al(OH) 3 , respectively. The reaction mechanism of the corrosion products on the aluminium surface was studied in detail and the reaction equations are shown in formulas (1) to (3).…”

“…The reason for the low degree of corrosion is the directional migration of corrosive Cl − ions caused by the DC current, which causes different Cl − ion concentrations in the liquid film on the positive and negative surfaces of the sample. 18 Under the current value of 25–75 A, except for the negative extreme of the sample under DC current, the degree of corrosion of the sample is significantly improved compared with that under the non-energised state, which means that the current has accelerated the corrosion of the copper–aluminium composites. It is worth noting that under the 100 A current, the degree of surface corrosion of the two current samples is lower than that under the non-energised state.…”

“…The mechanism of the effect of the service current on the corrosion acceleration of copper-aluminium composites has been well studied in our previous works. 18,19 In this work, the current can improve the corrosion ability of Cl − ions by increasing the activity of the Cl − ions in the liquid film, which further affects the corrosion behaviour of the copper-aluminium composites. In addition, DC current will also cause the directional migration of ions, resulting in the different degrees of corrosion between the two ends of the sample.…”

“…In the previous studies, the transformation of the salt spray equipment has been optimised, and salt spray accelerated corrosion tests have been realised under the energised state, initially revealing the influence mechanism of fixed current on the corrosion behaviour of copper-aluminium composites under the specified current state. [18][19][20][21] Despite these achievements, the differences between the effects of the two kinds of current on the corrosion mechanism of copper-aluminium composites have not been systematically explored. To sum up, in order to explore the mechanism of the effect of the service current on the corrosion behaviour of copper-aluminium composites, accelerated corrosion experiments on the composites were carried out at the condition of AC current and DC current energisation in the environment of 3 wt% neutral NaCl salt spray.…”