| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Coatings and Surface Engineering for Environmental Protection II
|
| Presentation Title |
Contact Resistance and Corrosion Response of Non-chromate Passivations on ZnNi Coatings |
| Author(s) |
Kevin L. Foster, William Fahrenholtz, Matthew O'Keefe, James Claypool |
| On-Site Speaker (Planned) |
Kevin L. Foster |
| Abstract Scope |
Two electrically conductive <100 nm thick non-chromate passivations on ZnNi coatings were studied, a trivalent chromium based passivation (TCP), and a cobalt-free TCP. Contact resistance measurements were taken according to MIL-STD-81706B and showed that unpolished panels had lower resistances than polished panels for both passivations. In addition, Co-Free TCP passivations tended to have lower resistance after salt spray exposure than TCP. Optical microscopy showed less corrosion after 1000 hours salt spray on Co-Free TCP, but open circuit potentials, chronopotentiodynamic scans, and electrochemical impedance spectra for both passivations suggested little change in chemical behavior at sample surface. Both passivations offer increased corrosion resistance compared with unpassivated samples and the removal of cobalt may increase the corrosion resistance of trivalent chromium based passivations. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |