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Development of quantitative techniques for the study of discharge events during plasma electrolytic oxidation processes

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dc.contributor.advisorClyne, Bill
dc.contributor.authorDunleavy, Christopher Squire
dc.date.accessioned2010-12-14T10:11:19Z
dc.date.available2010-12-14T10:11:19Z
dc.date.issued2010-10-12
dc.description.abstractPlasma electrolytic oxidation, or PEO, is a surface modification process for the production of ceramic oxide coatings upon substrates of metals such as aluminium, magnesium and titanium. Two methodologies for the quantitative study of electrical breakdown (discharge) events observed during plasma electrolytic oxidation processes were developed and are described in this work. One method presented involves direct measurement of electrical breakdowns during production of an oxide coating within an industrial scale PEO processing arrangement. The second methodology involves the generation and measurement of electrical breakdown events through coatings pre-deposited using full scale PEO processing equipment. The power supply used in the second technique is generally of much lower power output than the system used to initially generate the sample coatings. The application of these techniques was demonstrated with regard to PEO coating generation on aluminium substrates. Measurements of the probability distributions of discharge event characteristics are presented for the discharge initiation voltage; discharge peak current; event total duration; peak instantaneous power; charge transferred by the event and the energy dissipated by the discharge. Discharge events are shown to increase in scale with the voltage applied during the breakdown, and correlations between discharge characteristics such as peak discharge current and event duration are also detailed. Evidence was obtained which indicated a probabilistic dependence of the voltage required to initiate discharge events. Through the scaling behaviour observed for the discharge events, correspondence between the two measurement techniques is demonstrated. The complementary nature of the datasets obtainable from different techniques for measurement of PEO discharge event electrical characteristics is discussed with regards to the effects of interactions between concurrently active discharge events during large scale PEO processing.en_GB
dc.identifier.doi10.17863/CAM.14259
dc.identifier.urihttp://www.dspace.cam.ac.uk/handle/1810/228637
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/228637
dc.language.isoenen_GB
dc.publisher.departmentDepartment of Materials Science and Metallurgyen_GB
dc.publisher.institutionUniversity of Cambridgeen_GB
dc.rightsAll Rights Reserveden
dc.rights.urihttps://www.rioxx.net/licenses/all-rights-reserved/en
dc.subjectPlasma electrolytic oxidationen_GB
dc.subjectMicro-arc oxidationen_GB
dc.subjectElectrolysisen_GB
dc.subjectSurface hardeningen_GB
dc.titleDevelopment of quantitative techniques for the study of discharge events during plasma electrolytic oxidation processesen_GB
dc.typeThesisen_GB
dc.type.qualificationlevelDoctoral
dc.type.qualificationnameDoctor of Philosophy (PhD)

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