E-Thesis 265 views
Next-generation automotive corrosion protective coatings based on novel pigments containing organic ions / GARETH JONES
Swansea University Author: GARETH JONES
DOI (Published version): 10.23889/SUThesis.70393
Abstract
In this thesis, different corrosion inhibitors and delivery systems are investigated as alternativesto current state of the art technologies to determine their influence on coating failure, focusingin particular on corrosion-driven cathodic delamination of organically coated hot dippedgalvanised ste...
| Published: |
Swansea University, Wales, UK
2025
|
|---|---|
| Institution: | Swansea University |
| Degree level: | Doctoral |
| Degree name: | EngD |
| Supervisor: | Williams, G. and Keil, P. |
| URI: | https://cronfa.swan.ac.uk/Record/cronfa70393 |
| Abstract: |
In this thesis, different corrosion inhibitors and delivery systems are investigated as alternativesto current state of the art technologies to determine their influence on coating failure, focusingin particular on corrosion-driven cathodic delamination of organically coated hot dippedgalvanised steel (HDG). In the work presented, electrochemical scanning techniques includingthe scanning Kelvin probe (SKP) and scanning vibrating electrode technique (SVET) areemployed to determine the influence of organic corrosion inhibitors when dispersed in anorganic coating, polyvinal butyral (PVB), or on a bare metal surface immersed in a 3.5 wt%NaCl solution.Different organic compounds were investigated with regard to their ability to reduce the ratesof cathodic delamination on HDG steel. Preliminary experiments involved incorporating theorganic compounds directly into PVB to determine their influence on cathodic delamination.2-mercaptobenzothiazole (2-MBT) provided the most effective protection, demonstrating nodelamination over 48 hours. 2-MBT was successfully exchanged into hydrotalcite (HT) in itsanionic form, to produce a smart release inhibitive pigment which significantly reduceddelamination rates of PVB over 48 hours but did not halt delamination.8-hydroxyquinoline (8-HQ) was investigated as a corrosion inhibitor for organically coatedHDG steel and on a bare metal defect. Initial results showed that dispersing 8-HQ directly intoan organic coating significantly reduced the rates of delamination. 8-HQ was exchange intoHT and amberlite, a cationic exchange resin, allowing 8-HQ to be stored in its cationic form.Neither form of stored inhibitor performed as effectively as direct coating additions.A novel organic inhibitor, phenanthroline, was investigated to observe its effect when HDGsteel is immersed in 3.5 wt% NaCl. A reduction in corrosion rates was observed as well as aprominent yellow film. However, due to the non-unform formation of the film, corrosion stillproceeded even at higher concentrations of phenanthroline Lastly, a cerium-based metal organic framework (MOF) was investigated as a delivery systemfor corrosion inhibitors. The MOF was dispersed into PVB and significantly reduceddelamination rates without the addition of any inhibitors. Incorporation of 8-HQ, 2-MBT andbenzotriazole (BTA) within the MOF showed a significant decrease in delamination with noneobserved with 2-MBT/MOF. |
|---|---|
| Keywords: |
Corrosion, Galvanised steel, Inhibitors, Cathodic Delamination, Organic coatings |
| College: |
Faculty of Science and Engineering |
| Funders: |
EPSRC |