Infrared spectroelectrochemical characterisation of corrosion processes at lacquer coated iron
Infrared spectroelectrochemical characterisation of corrosion processes at lacquer coated iron
The aim of the work was to characterise the processes involved in the breakdown of protective lacquer films used to coat the inside of food and beveraged cans. The investigation utilised both conventional electrochemical measurements and in-situ infrared spectroelectrochemistry in order to elucidate at the molecular level the degradation processes within the thin polymer layer and identify corrosion processes at the metal surface.
Results from the following sets of investigations will be discussed.
1. The adsorption on a gold electrode of model organic compounds related to the monomeric units of the polymer films. Cyclic voltammetry and differential capacity measurements were used to define the overall adsorption and reaction behaviour of the monomers. In-situ infrared spectroelectrochemistry, SNIFTIRS, was used to determine the orientation of the adsorbates. The magnitude of the carbon/carbon stretching modes of the aromatic ring at 1500 cm-1 and 1600 cm-1 together with the characteristic band at 1240 cm-1 from the ether unit were found to be particularly useful in determining the orientation of the adsorbates with respect to the metal surface.
2. The time and potential dependence of the properties of the polymer layer on gold and iron metals in contact with a variety of aqueous electrolytes. Difference spectra taken over a wide time scale gave information on the transport of electrolyte through the polymer film and the onset of corrosion of the active metal surface. Spectra from 5 μm thick, non-crosslinked epoxy polymer layers showed changes in the layer and the ingress of electrolyte starting on a time scale of a few minutes. The spectra of corrosion products on the iron surface could be detected at quite short times and the oxidative degradation of the polymer could be seen at more positive potentials.
University of Southampton
1993
Port, Simon Nigel
(1993)
Infrared spectroelectrochemical characterisation of corrosion processes at lacquer coated iron.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The aim of the work was to characterise the processes involved in the breakdown of protective lacquer films used to coat the inside of food and beveraged cans. The investigation utilised both conventional electrochemical measurements and in-situ infrared spectroelectrochemistry in order to elucidate at the molecular level the degradation processes within the thin polymer layer and identify corrosion processes at the metal surface.
Results from the following sets of investigations will be discussed.
1. The adsorption on a gold electrode of model organic compounds related to the monomeric units of the polymer films. Cyclic voltammetry and differential capacity measurements were used to define the overall adsorption and reaction behaviour of the monomers. In-situ infrared spectroelectrochemistry, SNIFTIRS, was used to determine the orientation of the adsorbates. The magnitude of the carbon/carbon stretching modes of the aromatic ring at 1500 cm-1 and 1600 cm-1 together with the characteristic band at 1240 cm-1 from the ether unit were found to be particularly useful in determining the orientation of the adsorbates with respect to the metal surface.
2. The time and potential dependence of the properties of the polymer layer on gold and iron metals in contact with a variety of aqueous electrolytes. Difference spectra taken over a wide time scale gave information on the transport of electrolyte through the polymer film and the onset of corrosion of the active metal surface. Spectra from 5 μm thick, non-crosslinked epoxy polymer layers showed changes in the layer and the ingress of electrolyte starting on a time scale of a few minutes. The spectra of corrosion products on the iron surface could be detected at quite short times and the oxidative degradation of the polymer could be seen at more positive potentials.
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Published date: 1993
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Local EPrints ID: 462246
URI: http://eprints.soton.ac.uk/id/eprint/462246
PURE UUID: 96dc72c7-7aa4-4357-9577-1e3fb3076f46
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Date deposited: 04 Jul 2022 19:04
Last modified: 04 Jul 2022 19:04
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Author:
Simon Nigel Port
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