Abstract
In this paper, the effect of temperature on the corrosion behavior and corrosion resistance of the copper–aluminum laminated composite plates were investigated by salt-spray corrosion, potential polarization curve and electrochemical impedance spectroscopy. Moreover, the microstructure of the copper–aluminum laminated composite plate after salt-spray corrosion was observed by scanning electron microscope, and X-ray photoelectron spectroscopy was used to study the composition of corrosion product. The results revealed that the corrosion products of the copper–aluminum laminated composite plate were Al2O3 and AlOOH. Due to the galvanic corrosion of the copper–aluminum laminated composite plate, the cathode underwent oxygen absorption corrosion during the corrosion process; therefore, the presence of moisture and the amount of dissolved oxygen in the corrosive environment had a great influence on the corrosion process. The increasing temperature would evaporate a large amount of moisture, resulting in the corrosion product—aluminum oxide dehydrated and covered the surface of the material in the process of salt-spray corrosion, which played a role in protecting the material. Therefore, the corrosion resistance of the copper–aluminum laminated composite plate first decreased and then increased. In the salt-spray corrosion environment, the corrosion resistance of the copper–aluminum laminated composite plate reached the lowest at 45 °C, and its corrosion rate was the fastest, at 0.728 g/m2·h. The electrochemical corrosion occurred in the solution, and the impact was small; however, in addition to the protective corrosion products, the ion mobility in the solution also had a certain influence on the corrosion rate, and the ionic activity increased with the increase of temperature. Therefore, the corrosion resistance of the copper–aluminum laminated composite plate gradually decreased as the temperature increased, and its corrosion resistance was the worst at 50 °C.
Highlights
Copper–aluminum laminated composite plates were widely applied to the chemical industry and electronics, due to their exceptional advantages, including superior electrical and thermal conductivity, favorable processing performance, and cut-price [1,2,3,4]
It was found that pitting corrosion appeared on the aluminum matrix first when the copper–aluminum galvanic couple was brought into contact with the corrosive medium [11,12,13]
With the temperature further rising up to 50 ◦ C, as shown in Figure 1e, crevice corrosion appeared accompanied by local diffusion corrosion, suggesting that the corrosion area on the aluminum matrix spread insufficiently and showed less corrosion products than at 45 ◦ C
Summary
Copper–aluminum laminated composite plates were widely applied to the chemical industry and electronics, due to their exceptional advantages, including superior electrical and thermal conductivity, favorable processing performance, and cut-price [1,2,3,4]. That aluminum had a low standard electrode potential (−1.662 V) compared with copper (+0.342 V)—made the copper–aluminum laminated composite plate experience severe galvanic corrosion when it was in a humid or corrosive medium environment. As in the marine environment with high Cl− concentration, severe pitting corrosion and peeling would initiate from the aluminum in the copper–aluminum galvanic couple, and it would develop into crevice corrosion along the interface between aluminum and copper [14,15]. It was demonstrated that multiple pitting pits appeared on the surface of the material within a short period of time in an aerobic environment; the corrosion reaction occurred rapidly and violently, yet basically the galvanic corrosion would not happen in materials without oxygen, and the corrosion potential did not fluctuate [11,17]. The copper–aluminum laminated composite material underwent galvanic corrosion, its corrosion behavior changed with the different service environment
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