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Title:Experimental and Theoretical Investigations of Electrode Shape Change Taking Place During Pitting Corrosion of Iron
Author(s):Reiser, David Bruce
Department / Program:Chemical Engineering
Discipline:Chemical Engineering
Degree Granting Institution:University of Illinois at Urbana-Champaign
Degree:Ph.D.
Genre:Dissertation
Subject(s):Engineering, Chemical
Abstract:The present study included experimental measurements of corrosion pit shapes and theoretical calculations on the effect of pit shape on the mass transport of dissolved metal ions within pits. The system studied was pure iron in 1N H(,2)SO(,4) containing small amounts of chloride ion.
Photogrammetric analysis was applied to stereo SEM micrographs of pits having diameters from 7 to 200 micrometers. Pit cross sections obtained from the analysis indicated that pits grew with a hemispherical shape up to a radius of 25 micrometers before evolving into forms which were shallower than hemispheres.
The finite element method was used to solve the steady-state convective-diffusion equation in the electrolyte phase in two-dimensional pits having width-to-depth ratios from 4 to 1/2. Boundary conditions included either a constant metal ion concentration or a constant ionic flux at the active pit surface. The resulting concentration fields obtained were used to predict the critical conditions of electrolyte flow, pit size, and pitting current density which would result in removal of corrosion products from the pits. The ability to compute mass transport rates inside individual multidimensional pits enables evaluation of various hypotheses of pitting corrosion mechanisms.
Issue Date:1983
Type:Text
Description:169 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
URI:http://hdl.handle.net/2142/69734
Other Identifier(s):(UMI)AAI8324629
Date Available in IDEALS:2014-12-15
Date Deposited:1983


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