At Forsmark, several cases of suspected galvanic corrosion have been detected and believed to be caused by an inappropriate use of graphite gaskets in brackish water. This report studies the likelihood of galvanic corrosion between the graphite gasket and stainless steels and aims to be a reference when investigating galvanic corrosion in the future. To evaluate galvanic corrosion, several electrochemical experiments were studied, such as galvanic series, polarization curves, and galvanic current measurements with a ZRA. The electrochemical results showed that when immersing the stainless steel (254 SMO) and the graphite gasket (Novatec) into brackish water, there was a current flowing between the electrodes. However, the current was very small, which could be explained by the protection from a passive film on the stainless steel. The difference in corrosion potential between the two materials was measured and compared to results from polarization curves. It appeared that 254 SMO would be protected by a passive film at the measured potential. Galvanic current measurements also indicated the presence of a passive film under the investigated conditions. The results indicate that galvanic corrosion itself should not have caused the corrosion attacks at Forsmark. The found corrosion is more likely due to crevice corrosion that was accelerated by the combination of a crevice, a welded flange surface, chlorides in water and possibly a graphite gasket.

Thesis (M.Phil.) -- Chinese Universtity of Hong Kong. / Includes bibliographies.

The main purpose of this thesis is to study on Galvanic electrochemical etch stop using Au/Si/TMAH formation and tries to find out the conditions that we make micro-structure should need. Through the formation of Au/Si/TMAH, the wafer which have PN junction etch in TMAH, P type Si would be etched and N type Si would be protected. This mechanism improves the following problem¡G(1) the stress problem that due to the heavily boron-doped etch stop; (2) the non-batch fabrication and thermal stress problem that electrochemical etch stop have to use external bias and holder protection. We use TMAH as an etchant. Its advantages are¡G(1) compatible with the COMS process, (2)adding the specific additive that can increase the selectivity of aluminum, even non-etch. The application of this research will be more elasticity. Finally, for testing and verifying the feasibility of the parameters, author applied the designing conditions to fabricate the beam structure.

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Thesis (Ph. D.)--University of Chicago, 1938. / Reproduced from type-written copy. "Private edition, distributed by the University of Chicago libraries, Chicago, Illinois." "List of references": p. 14-16.

Thesis--Wisconsin. / Includes bibliographical references (leaves 27-29).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1964. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 70-71).

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