Abstract
Corrosion inhibition of AZ31 Mg alloy with aqueous vanadate was studied and has been attributed to the pH dependence of vanadate speciation. Immersion in tetrahedral coordinated vanadate species, present in neutral and alkaline solution, was shown to decrease corrosion current density and increase the breakdown potential, both of which were enhanced with longer immersion times. Exposure to octahedral coordinated vanadate, predominant in acidic solution, only slightly decreased corrosion current density. An acidic solution was adjusted to alkaline conditions and samples were immersed in the adjusted alkaline solution. Inhibition of these samples was weaker than that of samples immersed in initially alkaline solutions. Anodic inhibition was observed on samples treated in solutions containing tetrahedral species. SEM images showed that vanadate formed a film across secondary particles and the Mg matrix, and provided qualitative evidence that inhibition efficiency increased as the pH increased. XPS results indicated that film formation was associated with the reductive adsorption of vanadium oxoions. Exposure at pH 5.0 produced a film predominated by V4+. Exposure at pH values of 7.7 and higher, however, produced a film containing predominantly V3+. Raman analysis confirmed the formation of a vanadate film on the Mg surface after exposure at all pH values.
| Original language | English |
|---|---|
| Pages (from-to) | C94-C102 |
| Journal | Journal of the Electrochemical Society |
| Volume | 165 |
| Issue number | 2 |
| DOIs | |
| State | Published - 2018 |
Bibliographical note
Publisher Copyright:© The Author(s) 2018.
Funding
Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF-14-2-0004. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. Purchase of the Ra-man microprobe was supported by the National Science Foundation under Grant No. 0639163. Research was sponsored by the Army Research Laboratory and was accomplished under Cooperative Agreement Number W911NF- 14-2-0004. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of the Army Research Laboratory or the U.S. Government. The U.S. Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein. Purchase of the Raman microprobe was supported by the National Science Foundation under Grant No. 0639163.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | 0639163 |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China | |
| Army Research Laboratory | W911NF-14-2-0004 |
| Army Research Laboratory | |
| U.S. Department of Energy Chinese Academy of Sciences Guangzhou Municipal Science and Technology Project Oak Ridge National Laboratory Extreme Science and Engineering Discovery Environment National Science Foundation National Energy Research Scientific Computing Center National Natural Science Foundation of China |
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Condensed Matter Physics
- Surfaces, Coatings and Films
- Electrochemistry
- Materials Chemistry
