Análisis de la Amplitud de las Señales de Emisión Acústica Generadas por Corrosión Bajo Tensión en Latón-α

The present work was aimed to characterize the acoustic emission (AE) response obtained during the propagation of stress corrosion cracks. The differences between the AE signals generated by transgranular and intergranular SCC were analyzed. For that purpose, slow strain rate tensile tests (SSRT) under potentiostatic control were performed. The systems studied were: 1) yellow brass in a 1M NaNO2 solution; 2) yellow brass in a Mattsson’s solution (0.05 M CuSO4 plus 1M (NH4)2SO4), pH 6.5. The AE signals generated by SCC propagation can be distinguished from signals originated by other processes simultaneously occurring on the metal surface (localized corrosion, metal dissolution, breakdown and repair of surface films, gas bubbles evolution) by setting the proper AE threshold value. The AE activity during the propagation of transgranular SCC was various orders of magnitude higher than the AE activity during the intergranular SCC propagation. The statistical analysis of the mean value of the amplitude showed that in all the systems studied the AE signals generated during SCC propagation were originated by the same process.