Engineering Commons^™

Optimization Of Titanium Liquid/Gas Diffusion Layers In Proton Exchange Membrane Electrolyzer Cells, Stuart Mccoy Steen

Masters Theses

Polymer electrolyte membrane electrolyzer cells (PEMECs), which are reverse PEM fuel cells (PEMFCs), are effective energy storage medium by producing hydrogen/oxygen from water using electricity from renewable energy sources. This is due in part because of its efficiency, high energy density, compact design, and large capacity. In a PEMEC, a liquid/gas diffusion layer (LGDL) is located between the catalyst layer and the current distributing flow field. The LGDL is expected to transport electrons, heat, and reactants/products to and from the catalyst layer with minimum voltage, current, thermal, interfacial, and fluidic losses. Carbon materials (carbon paper or carbon cloth), typically used …

Isolating Corrosion Of Steel Plates Coupled With Titanium, Anil Patnaik, X. Shan, M. Adams, T. Srivatsan, Craig Menzemer, Joe Payer

Craig Menzemer

Over twenty six percent of the bridges in the United States are structurally deficient or functionally obsolete. Corrosion of steel used in structures like bridges and buildings is a problem that has gained increased interest and focused concern. Steel is often the metal that is preferred for use in such applications due to a synergism of ease of availability, acceptable mechanical properties and cost effectiveness. Through the years, titanium has grown in strength, stature and significance to be recognized as an emerging high performance metal that is both stronger and lighter than steel. A distinctive property of titanium and its …

Extrinsic Influence Of Environment On The Corrosion Behaviour Of Enamel-Coated Steel Dowel Bars, Srikanth Bajaj, Anil Patnaik, Joe Payer, Robert Liang, Kannan Manigandan, Tirumalai Srivatsan

Anil Patnaik

A new type of enamel coated dowel bars for use as concrete pavements has been recently developed and implemented. A gradual deterioration of such bars can occur due to corrosion occurring at locations of the fine microscopic cracks and other defects in the coating. The results of a study aimed at evaluating and understanding the corrosion resistance of such dowel bars is presented and comparisons made with corresponding epoxy-coated dowel bars. Identical defects were introduced onto the surface of the dowel bars with the two types of coatings. The extrinsic influence of environment and resultant corrosion based on type, location …

Isolating Corrosion Of Steel Plates Coupled With Titanium, Anil Patnaik, X. Shan, M. Adams, T. Srivatsan, Craig Menzemer, Joe Payer

Anil Patnaik

Over twenty six percent of the bridges in the United States are structurally deficient or functionally obsolete. Corrosion of steel used in structures like bridges and buildings is a problem that has gained increased interest and focused concern. Steel is often the metal that is preferred for use in such applications due to a synergism of ease of availability, acceptable mechanical properties and cost effectiveness. Through the years, titanium has grown in strength, stature and significance to be recognized as an emerging high performance metal that is both stronger and lighter than steel. A distinctive property of titanium and its …

Extrinsic Influence Of Environment On The Corrosion Behaviour Of Enamel-Coated Steel Dowel Bars, Srikanth Bajaj, Anil Patnaik, Joe Payer, Robert Liang, Kannan Manigandan, Tirumalai Srivatsan

Robert Y. Liang

A new type of enamel coated dowel bars for use as concrete pavements has been recently developed and implemented. A gradual deterioration of such bars can occur due to corrosion occurring at locations of the fine microscopic cracks and other defects in the coating. The results of a study aimed at evaluating and understanding the corrosion resistance of such dowel bars is presented and comparisons made with corresponding epoxy-coated dowel bars. Identical defects were introduced onto the surface of the dowel bars with the two types of coatings. The extrinsic influence of environment and resultant corrosion based on type, location …

Swelling-Etching Characterization Of Copper (I) Oxide - Pdms For The Development Of Micro/Nano - Particles Composite Mems Corrosion Sensor, Abdoul Kader Maiga

Graduate Theses and Dissertations

The primary objective for this thesis is to contribute to the understanding of the oxide removal process for a corrosion sensing device. The goal for designing such a device is for monitoring corrosion on metallic structures. The sensing material (6.35mm x 1mm discs) of the device is composed of copper (I) oxide particles mixed in some polydimethylsiloxane (PDMS). The PDMS, “housing,” is meant for controlling the oxidation rate through the sensing material. A solvent was used to facilitate the etchant diffusion through the PDMS matrix. Toluene and acetic acid were the ideal solvent and etchant, respectively, for carrying out the …

The Microstructure And The Electrochemical Behavior Of Cobalt Chromium Molybdenum Alloys From Retrieved Hip Implants, Christopher P. Emerson

FIU Electronic Theses and Dissertations

Because of their excellent mechanical, tribological, and electrochemical properties, Cobalt Chromium Molybdenum alloys have been used as the material for both the stem and head of modular hip implants. Corrosion is one mechanism by which metal debris, from these implants, is generated, which can lead to adverse events that requires revision surgery. Manufacturing process such as wrought, as-cast, and powder metallurgy influences the microstructure, material properties, and performance of these implants

The current research focuses on analyzing the microstructure of CoCrMo alloys from retrieved hip implants with optical and scanning electron microscopy. Additionally, energy disperse spectroscopy was utilized to determine …

In-Vivo Corrosion And Fretting Of Modular Ti-6al-4v/Co-Cr-Mo Hip Prostheses: The Influence Of Microstructure And Design Parameters, Jose Luis Gonzalez Jr

FIU Electronic Theses and Dissertations

The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobalt-chrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components. Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown …