Abstract
The electro-dissolution behaviour of a (30 at.%) Niobium–Titanium (NbTi) alloy in non-aqueous methanolic sulfuric acid solution using the rotating disc electrode (RDE) was ascertained. The optimal condition for electropolishing and the mechanism were proposed. The influence of the rotation rate, process temperature and sulfuric acid concentration on the dissolution kinetics was investigated. The dissolution rate (limiting current) increases linearly with increase in rotation rate and follows a Levich behaviour confirming a mass transport controlled process. The temperature dependence in terms of Arrhenius plot renders an activation energy value of Ea = 16.1 kJ mol−1 for the process. The dissolution rate shows a strong dependence on the sulfuric acid concentration (1 M, 3 M and 5 M). Higher sulfuric acid concentrations lead to decreased dissolution rates (limiting current). The dissolution process is mass transport controlled in all concentrations of sulfuric acid. From an electrochemical perspective, a 3 M sulfuric acid was chosen as optimum owing to better controllability of the material removal rate. The dissolving ions are the probable rate limiting species, indicating a compact salt-film mechanism. The average root mean square (RMS) roughness value for an electropolished surface was approximately 10 nm, which is significantly lower than a mechanically polished surface.
| Original language | English |
|---|---|
| Pages (from-to) | 6678-6682 |
| Number of pages | 5 |
| Journal | Electrochimica Acta |
| Volume | 56 |
| DOIs | |
| Publication status | Published - May 2011 |
Fields of science
- 104005 Electrochemistry
- 104006 Solid state chemistry
- 104014 Surface chemistry
- 104017 Physical chemistry
- 105113 Crystallography
- 105116 Mineralogy
- 503013 Subject didactics of natural sciences
- 204 Chemical Process Engineering
- 204001 Inorganic chemical technology
- 205016 Materials testing
- 210006 Nanotechnology
- 211104 Metallurgy
JKU Focus areas
- Engineering and Natural Sciences (in general)