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dc.contributor.advisorBobji, M S
dc.contributor.advisorMadras, Giridhar
dc.contributor.authorPendyala, Prashant
dc.date.accessioned2018-01-11T18:10:04Z
dc.date.accessioned2018-07-31T05:47:44Z
dc.date.available2018-01-11T18:10:04Z
dc.date.available2018-07-31T05:47:44Z
dc.date.issued2018-01-11
dc.date.submitted2014
dc.identifier.urihttp://etd.iisc.ac.in/handle/2005/3011
dc.identifier.abstracthttp://etd.iisc.ac.in/static/etd/abstracts/3877/G26758-Abs.pdfen_US
dc.description.abstractSurface roughness exists at many length scales-from atomic dimensions to meters. At sub-micron scale, the distribution of roughness is largely dependent on the process that generates the surface through the mechanisms of material removal/addition involved and the process parameters. The focus of the research is to quantitatively characterize the evolution of sub-micron scale surface roughness in the mechanical, chemical and electrochemical material removal techniques and study the influence of roughness on the mechanical behavior of surfaces. High purity aluminum surfaces are subjected to surface dissolution techniques such as electropolishing, chemical etching and anodization. Owing to the lack of sufficient lateral resolution in conventional roughness measurement techniques and appropriate scale independent roughness characterization techniques, the effect sub-micron scale electrochemical inhomogeneities present on the surfaces have on the roughness evolution at various length scales has not been understood. In this work, the power spectral density method of roughness characterization is used to quantitatively evaluate the roughness length scales affected in the surface generation processes as a function of time. Results indicate that in the case of electropolishing, roughness is not uniformly reduced at all length scales. Further, cut-off frequencies are suggested to optimize the electropolishing process. In chemical etching, the nature of roughness produced is found to be dependent on the nature of the starting surface. The nature of surface and sub-surface structures produced in the initial stage of the anodization process, and the transition from a disordered to an ordered structure are studied. In order to study the mechanical behavior of surfaces as a function of surface roughness, a single asperity indentation is modeled using nanoindentation of micropillar produced by focused ion beam machining of aluminum surfaces. Load-displacement curves are constructed to show the transition from a single asperity deformation to bulk deformation as function of indentation depth. Additionally, indentation responses of polymer coated surfaces with varying degree of roughness that were produced by the aforementioned surface generation processes are studied. it is shown how high interface roughness gives rise to high scatter both in loading and unloading portions of the load-displacement curves. Finally, porous alumina surface generated by the anodization process discussed above is indented to simulate a multi-asperity interaction.en_US
dc.language.isoen_USen_US
dc.relation.ispartofseriesG26758en_US
dc.subjectNanoscale Surface Roughnessen_US
dc.subjectElectropolishingen_US
dc.subjectChemical Etchingen_US
dc.subjectAnodizationen_US
dc.subjectAluminium Surfacesen_US
dc.subjectSurface Generationen_US
dc.subjectSurface Mechanical Behavioren_US
dc.subjectSurface Indentationen_US
dc.subjectSurface Roughnessen_US
dc.subjectAluminum Surfacesen_US
dc.subjectSurface Roughness Modelen_US
dc.subject.classificationNanotechnologyen_US
dc.titleGeneration, Characterization and Control of Nanoscale Surface Roughnessen_US
dc.typeThesisen_US
dc.degree.namePhDen_US
dc.degree.levelDoctoralen_US
dc.degree.disciplineFaculty of Engineeringen_US


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