Mössbauer study of the effect of electrochemical polishing on alpha-FeMn alloys

M. A. DAPINO; S. M. COTES; A. F. CABRERA; R. MERCADER; J. DESIMONI

Ciudad de Panamá, Panamá

Congreso; Latin American Conference on Applications of the Mössbabuer Effect (LACAME’2002); 2002

LACAME´2002, Departamento de Química Física, Facultad de Ciencias Naturales, Exactas y Tecnología, Universidad de Panamá

<!-- @page { size: 21.59cm 27.94cm; margin: 2cm } P { margin-bottom: 0.21cm } --> Obtaining transmission geometry Mössbauer spectra of Fe-alloys requires of thin samples, with a thickness of 70-90 μm, in order to avoid complex thin absorber corrections. Different treatments (cold working, coarse grinding) are employed to reach that condition, but usually they introduce undesirable distortion and phase transformations in the sample. We explore the use of the electrochemical polishing method for Fe-Mn sample thinning. One question to solve is the effect of the electrochemical attack on the sample composition, because of differences in the oxidation potential of Fe and Mn atoms in the alloy. Hence, in this work we focus on a thick (~ 1 mm) bcc (alpha) Fe-13.7 wt % Mn sample which is studied with CEMS and XCEMS previous and before electrochemical attack with a 5% perchloric acid in acetic acid solution, for different condition of attack. After that, the sample is electrochemical thinning to reach the suitable thickness to perform transmission Mössbauer spectroscopy. From comparison of the spectra and analysis using the random distribution approximation, we evaluate the electrochemical polishing method to use as a confident method for sample thinning.