Hydrogen mapping in an aluminum alloy using an alternating current scanning electrochemical microscope (AC-SECM)

• Published in: Electrochemistry communications 2017-07, Vol.80, p.29-32
• Main Authors: Lafouresse, Manon Chloé, de Bonfils-Lahovary, Marie-Laetitia, Laffont, Lydia, Blanc, Christine
• Format: Article
• Language: English
• Subjects: Alternating current scanning electrochemical microscopy (AC-SECM); Aluminum alloys; Chemical and Process Engineering; Chemical Sciences; Condensed Matter; Engineering Sciences; Hydrogen absorption; Hydrogen desorption; Material chemistry; Materials; Materials Science; Physics; Scanning Kelvin probe force microscopy (SKPFM)
• ISSN: 1388-2481; 1873-1902
• DOI: 10.1016/j.elecom.2017.05.007

Measurements using an alternating current scanning electrochemical microscope (AC-SECM) were performed on a 2024 aluminum alloy pre-charged with hydrogen. A gradient in AC current magnitude was observed over several hundreds of microns on the side perpendicular to the charging side. After heat treatment at 130°C for 2h, the current gradient disappeared. Comparison with scanning Kelvin probe force microscopy (SKPFM) measurements confirmed that the increase in AC current magnitude observed with AC-SECM was due to the presence of hydrogen in the material. Fitting of localized impedance spectra with a suitable equivalent circuit showed the influence of H on the corrosion rate. AC-SECM is thus a powerful new method to detect hydrogen and study its effect on corrosion at the micrometer scale. [Display omitted] •3D map of H distribution in pre-charged aluminum alloys obtained with AC-SECM.•AC-SECM allows H detection at a μm scale.•Measurements performed in situ in electrolyte with no mediator redox.•Similar gradients as in SKPFM observed for H absorption.•H influences the reactivity of AA 2024.