A comparative study on the passivation and localized corrosion of α, β, and α + β brass in borate buffer solutions containing sodium chloride : I. Electrochemical data
The passivation and localized corrosion of α-, β-, and (α + β)-brass in borate-boric acid buffer solutions (pH 9) containing different NaCl concentrations (c<sub>NaCl</sub>) were studied comparatively using conventional electrochemical techniques at 25 °C. The passivation of brass in bor...
| Autores: | , , , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 1995 |
| País: | Argentina |
| Institución: | Universidad Nacional de La Plata |
| Repositorio: | SEDICI (UNLP) |
| Idioma: | inglés |
| OAI Identifier: | oai:sedici.unlp.edu.ar:10915/80404 |
| Acceso en línea: | http://sedici.unlp.edu.ar/handle/10915/80404 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias Exactas Química Boratos Cloruro de Sodio Electroquímica Corrosión Boricum Acidum Ácidos Bóricos Técnicas Electroquímicas |
| Sumario: | The passivation and localized corrosion of α-, β-, and (α + β)-brass in borate-boric acid buffer solutions (pH 9) containing different NaCl concentrations (c<sub>NaCl</sub>) were studied comparatively using conventional electrochemical techniques at 25 °C. The passivation of brass in borate-boric acid buffer was due to the electroformation of a complex passive layer consisting of ZnO · xH<sub>2</sub>O and Cu<sub>2</sub>O—CuO. In NaCl-containing borate-boric acid buffer the breakdown of the passive layer occurs leading to pitting corrosion when the applied potential exceeds a certain critical value, E<sub>b</sub>. For a given type of brass, the value of E<sub>b</sub> is shifted negatively as c<sub>NaCl</sub> is increased. At a constant c<sub>NaCl</sub> the localized corrosion resistance of brass increases in the following order (α + β)-brass ≅ β-brass < α-brass. For all brass the localized corrosion resistance was lower than that of polycrystalline Cu, but considerably greater than that of polycrystalline Zn. Passive film composition and de-alloying can account for the localized corrosion resistance of these alloys. |
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