Premium
On the Electropolishing Mechanism of Nickel Titanium in Methanolic Sulfuric acid − An Electrochemical Impedance Study
Author(s) -
Fushimi Koji,
Neelakantan Lakshman,
Eggeler Gunther,
Hassel Achim Walter
Publication year - 2018
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201800011
Subject(s) - electropolishing , sulfuric acid , nickel , electrochemistry , titanium , mechanism (biology) , materials science , electrical impedance , metallurgy , chemistry , inorganic chemistry , chemical engineering , electrode , electrolyte , engineering , philosophy , epistemology , electrical engineering
Electropolishing of NiTi shape memory alloys is possible in methanolic 3 m H 2 SO 4 . The electro‐dissolution behavior of NiTi in methanolic 3 m H 2 SO 4 is ascertained in terms of Nyquist plots using electrochemical impedance spectroscopy (EIS) under limiting current flow (mass transfer control) condition. The electro‐dissolution behavior is studied under convective conditions using a rotating disc electrode. The influence of changes in rotation rate, applied potential, and temperature are determined. This study demonstrates that electro‐dissolution under mass transfer condition follows a compact salt‐film mechanism. In order to quantitatively characterize the salt film formed during electropolishing, EIS is performed under stationary conditions. The increase in applied voltage causes an increase in polarization resistance and decrease in capacitance of the interface film.