Microstructure and corrosion behavior of Cu-based alloys containing Al-Ag after normalizing and annealing heat treatments

• Published in: Journal of solid state electrochemistry Vol. 27; no. 11; pp. 2937 - 2946
• Main Authors: Flores-Sanchez, D., Suárez-Rosales, M. A., Landa-Castro, M., Gutiérrez-Arzaluz, M., Palomar-Pardavé, M., Romero-Romo, M. A.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2023; Springer Nature B.V
• Subjects: Aluminum bronzes; Analytical Chemistry; Annealing; Anodic polarization; Carbon steels; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Condensed Matter Physics; Copper; Copper base alloys; Corrosion; Corrosion effects; Corrosion resistance; Electrochemical impedance spectroscopy; Electrochemistry; Energy Storage; Heat treating; Heat treatment; Linear polarization; Microscopy; Microstructure; Normalizing (heat treatment); Optical microscopy; Original Paper; Pearlite; Physical Chemistry; Sodium chloride; Heat treatment; Corrosion; Microstructure; Copper alloys; Aluminum bronze; EIS
• ISSN: 1432-8488; 1433-0768
• DOI: 10.1007/s10008-023-05565-z

The alloys of the aluminum bronze system contain 5–14wt% Al that can be heat treated giving as result of different microstructures that were characterized by optical microscopy and scanning electron microscopy. This work aimed at investigating the influence of the microstructures of a Cu-9Al-3Ag alloy obtained after normalizing and annealing heat treatments, on the corrosion behavior in a saline medium containing 0.5 M sodium chloride, NaCl. The corrosion effect on the phases compounding the overall microstructures as result of immersing the samples in the corrosive medium was evaluated using cyclic voltammetry, potentiodynamic polarization curves, and electrochemical impedance spectroscopy. The results showed that normalizing and annealing heat treatments redefined the distribution of the α phase and, in addition led to formation of proeutectoid pearlite (α + γ 2 ), which is a microstructural constituent configured similarly to that present in diverse carbon steels, though in this case displaying a sequence of alternate lamellae of α and γ 2 , respectively. From the results of the linear polarization plots, the maximum anodic potentials became apparent, just like the regions where the trend of the graph gave the impression that passivation were to gain control. Likewise, the Tafel plots and impedance tests evidenced that the as-cast and normalized samples exhibited a better resistance to corrosion, at variance with the results of the annealed sample.