Anodic dissolution of cobalt in aqueous sodium nitrate solution at high current densities

2014 ◽  
Vol 66 (6) ◽  
pp. 549-556 ◽  
Author(s):  
M. Schneider ◽  
N. Schubert ◽  
S. Höhn ◽  
A. Michaelis
Keyword(s):  
Anodic Dissolution ◽  
Sodium Nitrate ◽  
Nitrate Solution ◽  
High Current ◽  
Aqueous Sodium ◽  
Current Densities ◽  
Sodium Nitrate Solution

Anodic dissolution of chromium at high current densities in sodium nitrate electrolyte

2018 ◽  
Vol 23 (2) ◽  
pp. 345-350
Author(s):  
M. Schneider ◽  
L. Simunkova ◽  
M. Manko ◽  
M. M. Lohrengel ◽  
W. Hoogsteen
Keyword(s):  
Anodic Dissolution ◽  
Sodium Nitrate ◽  
High Current ◽  
Current Densities

Physico-chemical studies of DL-alanine in aqueous sodium nitrate solution

2015 ◽  
Vol 85 (1) ◽  
pp. 162-167 ◽  
Author(s):  
S. Roy ◽  
K. Mahali ◽  
S. Mondal ◽  
R. P. Mondal ◽  
B. K. Dolui
Keyword(s):  
Sodium Nitrate ◽  
Nitrate Solution ◽  
Aqueous Sodium ◽  
Physico Chemical ◽  
Chemical Studies ◽  
Sodium Nitrate Solution

scholarly journals Oxide Formation during Transpassive Material Removal of Martensitic 42CrMo4 Steel by Electrochemical Machining

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 402
Author(s):  
Daniela Zander ◽  
Alexander Schupp ◽  
Oliver Beyss ◽  
Bob Rommes ◽  
Andreas Klink
Keyword(s):  
Sodium Nitrate ◽  
Mixed Oxide ◽  
Material Removal ◽  
Nitrate Solution ◽  
Electrochemical Machining ◽  
Metal Dissolution ◽  
Oxide Formation ◽  
Current Densities ◽  
Sodium Nitrate Solution ◽  
Anodic Metal Dissolution

The efficiency of material removal by electrochemical machining (ECM) and rim zone modifications is highly dependent on material composition, the chemical surface condition at the break through potential, the electrolyte, the machining parameters and the resulting current densities and local current density distribution at the surfaces. The ECM process is mechanistically determined by transpassive anodic metal dissolution and layer formation at high voltages and specific electrolytic compositions. The mechanisms of transpassive anodic metal dissolution and oxide formation are not fully understood yet for steels such as 42CrMo4. Therefore, martensitic 42CrMo4 was subjected to ECM in sodium nitrate solution with two different current densities and compared to the native oxide of ground 42CrMo4. The material removal rate as well as anodic dissolution and transpassive oxide formation were investigated by mass spectroscopic analysis (ICP-MS) and (angle-resolved) X-ray photoelectron spectroscopy ((AR)XPS) after ECM. The results revealed the formation of a Fe3−xO4 mixed oxide and a change of the oxidation state for iron, chromium and molybdenum, e.g., 25% Fe (II) was present in the oxide at 20.6 A/cm2 and was substituted by Fe (III) at 34.0 A/cm2 to an amount of 10% Fe (II). Furthermore, ECM processing of 42CrMo4 in sodium nitrate solution was strongly determined by a stationary process with two parallel running steps: 1. Transpassive Fe3−xO4 mixed oxide formation/repassivation; as well as 2. dissolution of the transpassive oxide at the metal surface.

Sign in / Sign up

Export Citation Format

Share Document