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Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings. / Nicholas Barnard

Swansea University Author: Nicholas Barnard

Abstract

A general modelling approach is described for the numerical simulation of localized corrosion phenomena. The model is demonstrated using several simple cases and compared both to analytical solutions and experimental measurements. The model is intended to operate at the microscopic-mesoscopic length...

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Published: 2006
Institution: Swansea University
Degree level: Doctoral
Degree name: EngD
URI: https://cronfa.swan.ac.uk/Record/cronfa42335
first_indexed 2018-08-02T18:54:27Z
last_indexed 2018-08-03T10:09:53Z
id cronfa42335
recordtype RisThesis
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spelling 2018-08-02T16:24:28.8697888 v2 42335 2018-08-02 Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings. 658a4caea8a3e379521081eed5b7dd0f NULL Nicholas Barnard Nicholas Barnard true true 2018-08-02 A general modelling approach is described for the numerical simulation of localized corrosion phenomena. The model is demonstrated using several simple cases and compared both to analytical solutions and experimental measurements. The model is intended to operate at the microscopic-mesoscopic length scales and involves two- or three-dimensional field calculations performed in a finite difference computational framework. Limitations and possible extensions to the algorithm are discussed. Experimental work has been reported that demonstrates the effects of microstructural variations within Zn-Al Galfan type coatings on the corrosion behaviour of cut-edge material, i.e. those cases where both the underlying steel and the organic coated Galfan layer are simultaneously exposed to a corrosive environment. An attempt to model the localized corrosion effects in electroplated zinc and hot-dip Galfan coatings has been made. The model combines both diffusive and electrochemical phenomena and describes corrosion effects on micro scale coating layers in NaCl electrolyte. The model predicts the 3D form of electrical potential, localized current densities and concentrations and also the time-dependent degradation of the micro scale coating layer. Results of the prototype model are quantitatively compared with measured current densities obtained from Scanning Vibrating Electrode Technique (SVET) studies. Simulations have been performed to predict the microstructural influence on the corrosion of Galfan coatings cooled at different rates. The model is in good agreement with experimental findings with respect to the cut-edge behaviour of these coatings, although contradicts those SVET measurements made in respect of the surface corrosion performance. E-Thesis Materials science. 31 12 2006 2006-12-31 COLLEGE NANME Engineering COLLEGE CODE Swansea University Doctoral EngD 2018-08-02T16:24:28.8697888 2018-08-02T16:24:28.8697888 Faculty of Science and Engineering School of Engineering and Applied Sciences - Uncategorised Nicholas Barnard NULL 1 0042335-02082018162446.pdf 10798043.pdf 2018-08-02T16:24:46.3570000 Output 25943562 application/pdf E-Thesis true 2018-08-02T16:24:46.3570000 false
title Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
spellingShingle Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
Nicholas Barnard
title_short Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
title_full Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
title_fullStr Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
title_full_unstemmed Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
title_sort Modelling the localized corrosion effects experienced by electroplated zinc and zinc - 4.5 wt.% aluminium steel coatings.
author_id_str_mv 658a4caea8a3e379521081eed5b7dd0f
author_id_fullname_str_mv 658a4caea8a3e379521081eed5b7dd0f_***_Nicholas Barnard
author Nicholas Barnard
author2 Nicholas Barnard
format E-Thesis
publishDate 2006
institution Swansea University
college_str Faculty of Science and Engineering
hierarchytype
hierarchy_top_id facultyofscienceandengineering
hierarchy_top_title Faculty of Science and Engineering
hierarchy_parent_id facultyofscienceandengineering
hierarchy_parent_title Faculty of Science and Engineering
department_str School of Engineering and Applied Sciences - Uncategorised{{{_:::_}}}Faculty of Science and Engineering{{{_:::_}}}School of Engineering and Applied Sciences - Uncategorised
document_store_str 1
active_str 0
description A general modelling approach is described for the numerical simulation of localized corrosion phenomena. The model is demonstrated using several simple cases and compared both to analytical solutions and experimental measurements. The model is intended to operate at the microscopic-mesoscopic length scales and involves two- or three-dimensional field calculations performed in a finite difference computational framework. Limitations and possible extensions to the algorithm are discussed. Experimental work has been reported that demonstrates the effects of microstructural variations within Zn-Al Galfan type coatings on the corrosion behaviour of cut-edge material, i.e. those cases where both the underlying steel and the organic coated Galfan layer are simultaneously exposed to a corrosive environment. An attempt to model the localized corrosion effects in electroplated zinc and hot-dip Galfan coatings has been made. The model combines both diffusive and electrochemical phenomena and describes corrosion effects on micro scale coating layers in NaCl electrolyte. The model predicts the 3D form of electrical potential, localized current densities and concentrations and also the time-dependent degradation of the micro scale coating layer. Results of the prototype model are quantitatively compared with measured current densities obtained from Scanning Vibrating Electrode Technique (SVET) studies. Simulations have been performed to predict the microstructural influence on the corrosion of Galfan coatings cooled at different rates. The model is in good agreement with experimental findings with respect to the cut-edge behaviour of these coatings, although contradicts those SVET measurements made in respect of the surface corrosion performance.
published_date 2006-12-31T07:21:04Z
_version_ 1828904935498973184
score 11.057409

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