No description available.

No description available.

Thesis (Ph.D.)--Ohio University, November, 2004. / Includes bibliographical references (p. 161-171)

Thesis (M.S.)--Ohio University, June, 2004. / Includes bibliographical references (p. 103-106).

Thesis (M.S.)--University of North Texas, Aug., 2009. / Title from title page display. Includes bibliographical references.

Thesis (M.S.)--Ohio University, June, 2004. / Title from PDF t.p. Includes bibliographical references (p. 103-106)

Thesis (Ph.D.)--Ohio University, November, 2004. / Title from PDF t.p. Includes bibliographical references (p. 161-171)

The consequences of corrosion are extremely costly and troublesome. In manufacturing companies, for instance, corrosion is considered a chronic problem that causes sudden disruptions in many segments of operation including processing, production, transportation, and containment of commodity products. Protection against corrosion is, therefore, important, as it helps achieve service life extension for metals and reduction in corrosion-related costs. Risk reduction for catastrophic structural failures and accident prevention can also be realized. Broader application of protective coatings and corrosion inhibiting agents remains one of the best technical practices in minimizing the effects of corrosion. This study introduces different classes of polymers and organic compounds and their potential use as new groups of corrosion preventing materials. Firstly, the use of semiluorinated perfluorocyclobutyl (PFCB) aromatic ether polymers as coatings for corrosion prevention was examined. PFCB polymers share several important characteristics with commercial fluoropolymers including chemical resistance, thermal stability, mechanical strength, and low surface energy, but with enhanced processability. Secondly, the use of very small amounts of azole-based aromatic compounds was shown to effectively inhibit corrosion in acidic medium. Compared to other inhibitor agents, these compounds have the advantage of being less complex, inexpensive, environmentally friendly, and synthesized in a one-step approach. Thirdly, the use of a tetradiglycidyl-ether-based epoxy-amine resin as corrosion resistant coating was investigated both in its intact and artificially-damaged forms. This epoxy resin, which can be infused with preform materials, has been used in the development of carbon fiber composites for aircraft applications. Finally, the capability of a superhydrophobic perfluorinated polymer nanocomposite coating to resist corrosion was evaluated. The coating also displayed superoleophilicity, which led to its additional use in separating oil-water mixtures. Standard electrochemical methods such as open circuit potential, electrochemical impedance spectroscopy, and potentiodynamic polarization were used to evaluate the corrosion protection performance. Several other analytical techniques were also employed to characterize the quality and structure of the protective materials and supplement the results acquired from electrochemical analyses.

<p> Multiple impact tests were performed on mild steel. The pulse durations ranged from 15 to 250 milliseconds. Peak stresses extending to 135,000 p.s.i. were attained. </p> <p> A dynamic model, based on dislocation dynamics, was derived for polycrystalline metals and made specific to mild steel. The model provided a means of indirectly determining the dislocation velocity-stress exponent 𝑛 by experiment. </p> <p> An empirical flow function was evaluated which related dynamic load conditions to plastic deformation. This function is a further extension of the dynamic model. Several dislocation parameters are grouped together to pennit experimental evaluation of the strain rate effect on crystalline material. </p> <p> Experimental studies indicated that a given strain: </p> <p> 1) if produced by a single pulse, can be estimated by evaluation of the flow function for that load-time trace, or, </p> <p> 2) if produced by multiple impacts, can be estimated by the cumulative flow function, a summation of the flow functions for all impact traces. </p> <p> The multiple impact tests established the flow function as an equation of state. The plastic deformation could then be determined for a given dynamic load as long as the strain history is known. </p> <p> The theoretical model was used to support the experimental findings. </p> / Thesis / Master of Engineering (ME)

D. Tech. Chemical, Metallurgical and Materials Engineering / Discusses the objective of this present study is to manufacture particulate-strengthening Zn-Al-SnO2-TiO2 composite alloy on mild steel from chloride and sulphate baths with the target of improving mechanical and anti-corrosion, wear properties for automotive and decorative applications. Sub-Objectives:To study the effect of Zn-Al-SnO2-TiO2 composite properties on mild steel substrate To investigate the novel multifunctional thin films evolution formed on mild steel and their tribological properties. To investigate thermo-mechanical recrystallization behaviour and its thermal instability.To study the anti-corrosion resistance performance of the electrofabricated quaternary Zn-Al-SnO2-TiO2 coatings.To draw attention to the functional processing parameters of Zn-Al-SnO2-TiO2 produced coatings for high durability.