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Full-Text Articles in Engineering

Passive Wireless Corrosion And Temperature Detection In High-Temperature Environments, Noah Lane Strader Jan 2024

Passive Wireless Corrosion And Temperature Detection In High-Temperature Environments, Noah Lane Strader

Graduate Theses, Dissertations, and Problem Reports

This work focuses on the theory and development of LC sensors for high temperature and corrosion measurement for stainless steel and copper surfaces with power industry and general corrosion detection applications. The LC resonators were fabricated via screen printing an Ag inductor on an alumina substrate. The LC design was modeled using the ANSYS HFSS modeling package. The LC passive wireless sensors operate with resonant frequencies centered at 85-110 MHz. The wireless response of the LC sensor was interrogated and received by a radio frequency signal generator and spectrum analyzer at temperatures from 50-800 °C for copper ground planes and …


The Study Of Corrosion On Additive-Manufactured Metals., Braydan Daniels May 2023

The Study Of Corrosion On Additive-Manufactured Metals., Braydan Daniels

Electronic Theses and Dissertations

The purpose of this study was to investigate and compare the corrosion mechanisms between wrought and additive-manufactured (3D-printed) copper and stainless steel. The experimental procedure consisted of measuring the open circuit potential, electrochemical impedance spectroscopy, linear sweep voltammetry, Tafel analysis, surface topology, and scanning electron microscopy for each metal within salt water, tap water, sulfuric acid, and synthetic body fluid (excluding copper in synthetic body fluid).

Overall, printed stainless steel was more corrosion-resistant than wrought stainless steel in tap water and synthetic body fluid based on OCP, LSV, and surface topology results. Additionally, printed copper was more corrosion-resistant than wrought …


Assessment Of Cu(In, Ga)Se₂ Solar Cells Degradation Due To Water Ingress Effect On The Cds Buffer Layer, Deewakar Poudel, Benjamin Belfore, Shankar Karki, Grace Rajan, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac Jan 2021

Assessment Of Cu(In, Ga)Se₂ Solar Cells Degradation Due To Water Ingress Effect On The Cds Buffer Layer, Deewakar Poudel, Benjamin Belfore, Shankar Karki, Grace Rajan, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac

Electrical & Computer Engineering Faculty Publications

The effect of water ingress on the surface of the buffer layer of a Cu(In, Ga)Se2 (CIGS) solar cell was studied. Such degradation can occur either during the fabrication process, if it involves a chemical bath as is often the case for CdS, or while the modules are in the field and encapsulants degrade. To simulate the impact of this moisture ingress, devices with a structure sodalime glass/Mo/CIGS/CdS were immersed in deionized water. The thin films were then analyzed both pre and post water soaking. Dynamic secondary ion mass spectroscopy (SIMS) was performed on completed devices to analyze impurity diffusion …


Degradation Mechanism Due To Water Ingress Effect On The Top Contact Of Cu(In,Ga)Se2 Solar Cells, Deewakar Poudel, Shankar Karki, Benjamin Belfore, Grace Rajan, Sushma Swaraj Atluri, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac Jan 2020

Degradation Mechanism Due To Water Ingress Effect On The Top Contact Of Cu(In,Ga)Se2 Solar Cells, Deewakar Poudel, Shankar Karki, Benjamin Belfore, Grace Rajan, Sushma Swaraj Atluri, Sina Soltanmohammad, Angus Rockett, Sylvain Marsillac

Electrical & Computer Engineering Faculty Publications

The impact of moisture ingress on the surface of copper indium gallium diselenide (CIGS) solar cells was studied. While industry-scale modules are encapsulated in specialized polymers and glass, over time, the glass can break and the encapsulant can degrade. During such conditions, water can potentially degrade the interior layers and decrease performance. The first layer the water will come in contact with is the transparent conductive oxide (TCO) layer. To simulate the impact of this moisture ingress, complete devices were immersed in deionized water. To identify the potential sources of degradation, a common window layer for CIGS devices—a bilayer of …


Microwave Detection Of Surface Breaking Cracks In Metallic Structures Under Heavy Corrosion And Paint, John Robert Gallion Jan 2019

Microwave Detection Of Surface Breaking Cracks In Metallic Structures Under Heavy Corrosion And Paint, John Robert Gallion

Masters Theses

"We live in the world of "aging infrastructures". In this environment, critical and heavily utilized infrastructure, i.e. ships, planes, bridges, etc., are operating at or beyond their designed age. Replacement is no longer an option and "retirement for cause" is the current approach to maintenance and replacement. Consequently, there is an ever-increasing demand for efficient and robust nondestructive evaluation (NDE) methods that can determine the physical health of these structures. Large structures, which are primarily made of metals, either steel or aluminum, are susceptible to high-stress cracking and corrosion. Stress-induced cracks in heavily corroded steel, used in bridges, railroads, storage …


Vertical Electrical Impedance Measurements On Concrete Bridge Decks Using A Large-Area Electrode, Jeffrey David Barton Aug 2018

Vertical Electrical Impedance Measurements On Concrete Bridge Decks Using A Large-Area Electrode, Jeffrey David Barton

Theses and Dissertations

In regions where chloride-based deicing salts are applied to bridge decks, corrosion of the interior steel reinforcement is a major problem. Vertical electrical impedance (VEI) is an effective measurement technique to quantitatively assess the cover protection on bridges against aggressive chemical penetration of reinforced concrete. In its current form, traditional vertical electrical impedance is time-consuming and destructive because a direct connection to the reinforcing steel is required to provide a ground reference. A new method using a large-area electrode (LAE) permits VEI measurement without a direct electrical connection to the steel reinforcement. The LAE creates a nondestructive, semi-direct, low impedance …


Nano-Channels Early Formation Investigation On Stainless Steel 316ti After Immersion In Molten Pb-Bi, Abu Khalid Rivai, Mardiyanto Mardiyanto, Annette Heinzel Apr 2017

Nano-Channels Early Formation Investigation On Stainless Steel 316ti After Immersion In Molten Pb-Bi, Abu Khalid Rivai, Mardiyanto Mardiyanto, Annette Heinzel

Makara Journal of Technology

Development of fuel cladding and structural materials in Pb-Bi environment, especially at high temperature, is a critical issue for the deployment of LFR (Lead alloy-cooled Fast Reactor) and ADS (Accelerator Driven Transmutation System). This is because of the corrosive characteristic of Pb-Bi to metals as constituent materials of fuel cladding and structural of the reactors. Corrosion test of a high-chromium austenitic stainless steel i.e. SS316Ti in molten Pb-Bi at 550 ºC has been carried out for about 300 hours continuously. The characterization using SEM-EDS (Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy) showed that an iron oxide as the outer …


Swelling-Etching Characterization Of Copper (I) Oxide - Pdms For The Development Of Micro/Nano - Particles Composite Mems Corrosion Sensor, Abdoul Kader Maiga Jul 2015

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 …


In Vitro Immersion Behavior Of Cold Sprayed Hydroxyapatite/Titanium Composite Coatings, Lin Lu, Xuan Joe Zhou, Pravansu Mohanty Apr 2014

In Vitro Immersion Behavior Of Cold Sprayed Hydroxyapatite/Titanium Composite Coatings, Lin Lu, Xuan Joe Zhou, Pravansu Mohanty

Electrical & Computer Engineering Publications

In previous study, dense and homogenous 20wt% HAP/Ti composite coatings were successfully deposited on Ti substrates by cold gas dynamic spray technique. The results revealed that the phase composition of the HAP in the deposit is identical to that of the precursor powder and the bonding strength of the deposit is comparable/better to that of the plasma sprayed HAP. A relatively higher corrosion current of HAP/Ti composite than that of pure Ti coating in simulated body fluid indicates a good bioactivity for composite coating. In the present study, in vitro immersion test is carried out for various period of time …


Delamination Detection In Concrete Using Disposable Impactors For Excitation, Anjali Narendra Patil Dec 2013

Delamination Detection In Concrete Using Disposable Impactors For Excitation, Anjali Narendra Patil

Theses and Dissertations

Delaminations in concrete bridge decks result primarily from corrosion of the reinforcing bars (or rebar). This corrosion leads to volumetric expansion of the rebar. When the rebar expands, concrete cracks, and there is a localized separation of the concrete cover from the underlying concrete. Impact-echo testing is an effective technique to map delaminations on concrete bridge decks. However, mapping speed is limited by necessary retrieval of the impactor for traditional tests. To achieve higher scanning speeds, it is advantageous to use both a non-contact measurement (air-coupled impact-echo) and disposable-impactor excitation. Disposable impactors have the potential advantage of achieving greater deck …


Multifunctional Corrosion Inhibition Behavior Of Zn-Al Calcined Layered Double Hydroxides For Steel Rebar In Nacl Solution, Xiao-Juan Zhang, Jing-Jing Wang, Shi-Gang Dong, Chang-Jian Lin Jun 2013

Multifunctional Corrosion Inhibition Behavior Of Zn-Al Calcined Layered Double Hydroxides For Steel Rebar In Nacl Solution, Xiao-Juan Zhang, Jing-Jing Wang, Shi-Gang Dong, Chang-Jian Lin

Journal of Electrochemistry

The Zn-Al layered double hydroxides (Zn-Al LDHs) and calcined products (Zn-Al CLDHs) were synthesized successfully under a routine air atmosphere. The results showed that both Zn-Al LDHs and Zn-Al CLDHs had obvious flake structures. The corrosion inhibition of Zn-Al CLDHs for steel rebar in NaCl solution was studied by electrochemical techniques. It was found that the corrosion rate of steel rebar decreased significantly after the steel rebar was treated by Zn-Al CLDHs in NaCl solution for 3 h. It was indicated that Zn-Al CLDHs could absorb Cl- and release OH- during their reconstruction process, which provided dual protection …


System For Detection Of Defects In Cables Of Bridge Structures, Emad Ismail Abdel Salam May 2013

System For Detection Of Defects In Cables Of Bridge Structures, Emad Ismail Abdel Salam

Theses and Dissertations

Over the last 75 years, many cable-supported bridges have been built in America, Europe, Asia and other parts of the world. However, over the years these bridges have aged and been exposed to environmental conditions such as rain, snow, de-icing and harmful chemicals. These conditions cause various levels of deterioration in bridges, particularly corrosion. Corrosion causes a loss of cross-section in the steel, adversely affecting the bridge's capacity to carry its service loads, and can possibly cause bridge failures. Although many methods have been attempted to inspect these bridges, most have offered limited success. In the recent years, it has …


Investigation Of The Telluric Effects Arising Along The Cathodically Protected Natural Gas Pipeline Between Karadeniz Ereğli And Düzce, Bi̇lal Demi̇rel, Hayri̇ Yalçin Jan 2013

Investigation Of The Telluric Effects Arising Along The Cathodically Protected Natural Gas Pipeline Between Karadeniz Ereğli And Düzce, Bi̇lal Demi̇rel, Hayri̇ Yalçin

Turkish Journal of Electrical Engineering and Computer Sciences

Cathodic protection is one of the most widely used applications for protecting underground and submarine metallic structures from corrosion. This method is based on providing the electrons, which metallic structures lose as a result of electrolytic reaction, by the cathodic protection system. However, from time to time, it may be possible that there is some unwanted interference input into the metallic structure in such applications. This study is aimed at ascertaining the existence, arising frequency, and magnitude of an interference called the telluric effect that is going in and out of the natural gas pipeline between Düzce and Karadeniz Ereğli …


Applications Of Electricity In The Rehabilitation And Health Monitoring Of Concrete Structures, Saiprasad Vaidya Jul 2009

Applications Of Electricity In The Rehabilitation And Health Monitoring Of Concrete Structures, Saiprasad Vaidya

Doctoral Dissertations

The dissertation research work presented herein consists of two separate findings: one investigates a potential new coating technique that could be used to rehabilitate deteriorated concrete sewer pipes, and the other researches inducing electrical conductivity into geopolymer concrete to serve as smart material by being able to sense stress changes. Both applications utilize electricity to enhance the performance and/or functionality of hardened cementitious materials.

Microbiologically induced corrosion (MIC) in concrete wastewater conveyance systems is a leading deterioration mechanism in such structures. This work focuses on breaking the MIC cycle by preventing colonization of the bacteria responsible for converting hydrogen sulfide …


Study On Electrochemical Impedance Spectroscopy Of Carbon Steel Eroded In Methyldiethanolamine Solution, Dong-Ping Wei, Rong-Zong Hu, Dan-Mei Pan, Wei-Xiong Huang, Rui Dong Nov 2007

Study On Electrochemical Impedance Spectroscopy Of Carbon Steel Eroded In Methyldiethanolamine Solution, Dong-Ping Wei, Rong-Zong Hu, Dan-Mei Pan, Wei-Xiong Huang, Rui Dong

Journal of Electrochemistry

Corrosion behavior of carbon steel in methyldiethanolamine(MDEA) solution was investigated by Electrochemical Impedance Spectroscopy(EIS).The results were showed that the corrosion rate of carbon steel in solution containing dissolved oxygen is higher than that in solution removed of dissolved oxygen before cathodic activation.They were reversed after cathodic activation.The corrosion rate is increased at first and then decreased when the concentration of MDEA is increased in the blank solutions.In the simulated solutions containing quantities of!heat-stable salts(HSS),the corrosion rate is decreased monotonously with increase of the MDEA concentration.As anodic polarization potential is increased,the EIS of carbon steel in HSS simulated solution showed characteristics …


Application Of Millimeter Wave, Eddy Current And Thermographic Methods For Detection Of Corrosion In Aluminum Substrate, Mohammad Tayeb Ahmad Ghasr, Adam C. Ryley, Sergey Kharkovsky, R. Zoughi, Gary Steffes Jul 2007

Application Of Millimeter Wave, Eddy Current And Thermographic Methods For Detection Of Corrosion In Aluminum Substrate, Mohammad Tayeb Ahmad Ghasr, Adam C. Ryley, Sergey Kharkovsky, R. Zoughi, Gary Steffes

Electrical and Computer Engineering Faculty Research & Creative Works

Aluminum structures exposed to the elements are susceptible to corrosion. Corrosion may cause various mechanical and structural deficiencies such as material thinning. It is desirable to rapidly detect and evaluate the properties of an aluminum substrate early in the corrosion process to avoid costly maintenance actions later. There are several nondestructive testing methods for this purpose. To investigate capabilities of millimeter wave, conventional eddy current, and flash thermography techniques for detection of large corrosion areas in aluminum substrates, two corroded samples were inspected with and without dielectric coating (appliqué). This paper presents the results of the c-scan imaging of these …


Corrosion Electrochemical Behavior Of Aluminum Flake Pigmented Water-Borne Epoxy Coating On Carbon Steel In Nacl Solution, Li-Li Xue, Li-Kun Xu, Qing-Fen Li, Hong-Qing Song, Wen-Juan Zhou, Guang-Zhang Chen May 2007

Corrosion Electrochemical Behavior Of Aluminum Flake Pigmented Water-Borne Epoxy Coating On Carbon Steel In Nacl Solution, Li-Li Xue, Li-Kun Xu, Qing-Fen Li, Hong-Qing Song, Wen-Juan Zhou, Guang-Zhang Chen

Journal of Electrochemistry

The corrosion electrochemical behavior of a water-borne epoxy coating pigmented with aluminum flake on carbon steel with artificial scratch defect was studied in 3.5% NaCl solution using electrochemical impedance spectroscopy(EIS)and scanning vibrating electrode technique(SVET).The results indicated that the defect presented anodic electroactivity at the initial stage of immersion,which extended gradually with time from the scratch into the neighboring coating,lowering the coating impedance.With further immersion,however,the electroactivity of the coating/steel interface decreased significantly due to the self-repairing of the corrosion products,causing an obvious increase of the coating impedance.In the later period of immersion,more scattered electroactive areas appeared under the coating because of …


Evaluation Of Microwave Reflection Properties Of Cyclically Soaked Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, K. E. Kurtis, R. Zoughi Oct 2005

Evaluation Of Microwave Reflection Properties Of Cyclically Soaked Mortar Based On A Semiempirical Electromagnetic Model, Shanup Peer, K. E. Kurtis, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Detection of chloride ingress and evaluation of its distribution and temporal movement in reinforced concrete structures is an important practical issue. Steel reinforcing bars embedded in good quality concrete are normally protected from corrosion. However, the presence of a sufficient concentration of free chloride ions in the region of the reinforcing steel can initiate the process of corrosion. Therefore, it is important to be able to detect ingress of chloride ions and their distribution in cement-based materials. Moreover, it is important to obtain this information nondestructively. In recent years, near-field microwave nondestructive evaluation methods, using open-ended rectangular waveguide probes, have …


Comparison Of Near-Field Millimeter-Wave Probes For Detecting Corrosion Precursor Pitting Under Paint, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, Russell A. Austin Aug 2005

Comparison Of Near-Field Millimeter-Wave Probes For Detecting Corrosion Precursor Pitting Under Paint, Mohammad Tayeb Ahmad Ghasr, Sergey Kharkovsky, R. Zoughi, Russell A. Austin

Electrical and Computer Engineering Faculty Research & Creative Works

Aircraft structural components such as wings and fuselages are constantly exposed to harsh environments, which make them susceptible to corrosion initiation and growth. To complicate matters, corrosion is normally hidden under paint and primer and cannot be visually detected until significant corrosion has occurred, causing the paint to blister. Corrosion of this type is usually preceded by the presence of corrosion precursor pitting. Hence, early detection of pitting is a critical issue in the maintenance of an aircraft and its structural components. Near-field microwave nondestructive testing techniques have been successfully used for detection of corrosion under paint, including very small …


Instrumentation Of Ysz Oxygen Sensor Calibration In Liquid Lead-Bismuth Eutectic, X. Wu, Jian Ma, Yingtao Jiang, B. Fu, W. Hang, J. Zhang, N. Li May 2005

Instrumentation Of Ysz Oxygen Sensor Calibration In Liquid Lead-Bismuth Eutectic, X. Wu, Jian Ma, Yingtao Jiang, B. Fu, W. Hang, J. Zhang, N. Li

Mechanical Engineering Faculty Research

Liquid lead-bismuth eutectic (LBE), a good candidate for the coolant in the subcritical transmutation blanket, is known to be very corrosive to the stainless steel that transports it. Such a corrosion problem can be prevented by producing and maintaining a protective oxide layer on the exposed surface of the stainless steel. Proper formation of the oxide layer critically depends on the accurate measurement and control of the oxygen concentration in liquid LBE. An oxygen sensor calibration/measurement apparatus has been designed and built to deliberately calibrate an yttria stabilized zirconia (YSZ) oxygen sensor. A detailed description of this system with its …


Electromagnetic Modeling Of Saltwater Ingress In Mortar At Microwave Frequencies, Shanup Peer, R. Zoughi, K. E. Kurtis May 2003

Electromagnetic Modeling Of Saltwater Ingress In Mortar At Microwave Frequencies, Shanup Peer, R. Zoughi, K. E. Kurtis

Electrical and Computer Engineering Faculty Research & Creative Works

Corrosion of reinforcing steel is a major cause of damage and deterioration in reinforced concrete structures. Therefore, as the presence of a sufficient concentration of chloride ions can lead to the onset of corrosion in embedded steel, it is of utmost importance to be able to determine the free salt content and its distribution in these materials. Moreover, it is important to obtain this information nondestructively. Previous investigations have shown the capability of near-field microwave nondestructive evaluation methods, using open-ended rectangular waveguide probes, to evaluate many important properties of cement-based materials. In this Investigation, the temporal microwave reflection properties of …


Microwave Reflection And Dielectric Properties Of Mortar Subjected To Compression Force And Cyclically Exposed To Water And Sodium Chloride Solution, Shanup Peer, Joseph Toby Case, Eric Gallaher, K. E. Kurtis, R. Zoughi Feb 2003

Microwave Reflection And Dielectric Properties Of Mortar Subjected To Compression Force And Cyclically Exposed To Water And Sodium Chloride Solution, Shanup Peer, Joseph Toby Case, Eric Gallaher, K. E. Kurtis, R. Zoughi

Electrical and Computer Engineering Faculty Research & Creative Works

Corrosion of the reinforcing steel is a major cause of damage and deterioration in reinforced concrete structures such as concrete bridge decks and columns. Chloride intrusion into concrete can lead to depassivation of the steel and initiation of corrosion. Thus, it is very important to be able to nondestructively detect and evaluate the free chloride content in concrete. Near-field microwave nondestructive testing techniques, using open-ended rectangular waveguide probes, have shown great potential for evaluating various properties of concrete, including the successful detection of sodium chloride added to mortar mixing water. In this study, several mortar samples are cyclically soaked in …


Corrosive Electrochemical Behavior Of Carbon Steel In Microbiological Medium, Jing Liu, Hong-Bo Fan, Hai-Ping Xu, Jia-Shen Zheng, Li-Ming Xu, Zong-Qiang Mao May 2002

Corrosive Electrochemical Behavior Of Carbon Steel In Microbiological Medium, Jing Liu, Hong-Bo Fan, Hai-Ping Xu, Jia-Shen Zheng, Li-Ming Xu, Zong-Qiang Mao

Journal of Electrochemistry

Sulfate_reducing bacteria(SRB)grows and propagates, PH of the solution is dropped from 7.5 to 5.8,and forms the biofilms on carbon steel in culture medium.The micro_environment on the surface of carbon steel is changed under the biofilms,the factors accelerate the formation of the pitting corrosion. When the biofilm on carbon steel is cleaned out,the surface of carbon steel have the non_uniform pitting corrosion. The activity of SRB and the porous structure of biofilms induced the initiation and development of the pitting corrosion of carbon steel.The process of microbiologically induced corrosion(MIC) involves the development of SRB activity,which promotes the permeation of gydrogen into …


Synthesis And Application Of Polymeric Corrosion Inhibitor For Reinforced Concrete, Weiwei Lin, Shengxian Wang, Jianqing Zhang Feb 1999

Synthesis And Application Of Polymeric Corrosion Inhibitor For Reinforced Concrete, Weiwei Lin, Shengxian Wang, Jianqing Zhang

Journal of Electrochemistry

A new polymer E Twas synthesized and used as a corrosion inhibitor for reinforced concrete. The inhibitive behavior and mechanism were studied with linear polarization ,Tafel polarization,EIS and XPS method in simulated pore solution system with concrete samples.The result showed that the polymer was a mixing type inhibitor. A 1% dosage was sufficient to imhibit the corrosion of steel in simulated pore solution system. The salt endurance was enhanced from 0.02 mol/L to 0.10 mol/L.The result also showed the good synergetic effect of NaNO 2,especially in low NaNO 2 concentration.The EIS showed that E_T has dual function on reinforced concrete,i.e.,densifying …


The Inhibition Of Amphipathic S- And N-Containing Compounds On Carbon Steel Corrosion, Wei Xing, Yibin Shan, Du Guo, Tianhog Lu, Shiquan Xi Feb 1996

The Inhibition Of Amphipathic S- And N-Containing Compounds On Carbon Steel Corrosion, Wei Xing, Yibin Shan, Du Guo, Tianhog Lu, Shiquan Xi

Journal of Electrochemistry

Ordered monolayers of S- and N-containing amphipathic corrosion inhibitors were depoitod onto the surfaces of carbon steel electrode with super-molecular assembly technique. The effect of molecular aggregation of monolayers on carbon steel corrosion in 0. 05 mol dl ̄(-3)H_2SO_4 and the mechanisms of these inhibitors were discussed in details. It was found that the transport of hydrated hydrogen ion to the surface of steel depends strongly on the inhibitor molecular aggregation in the monolayers.


Optical Fiber Fourier Transform Infrared Evanescent Wave Absorption Spectroscopy Of Aluminum Hydroxide And Natural Corrosion, Juock S. Namkung Jan 1996

Optical Fiber Fourier Transform Infrared Evanescent Wave Absorption Spectroscopy Of Aluminum Hydroxide And Natural Corrosion, Juock S. Namkung

Electrical & Computer Engineering Theses & Dissertations

A new technique for continuous, real-time, in-situ detection of natural corrosion of aluminum alloys is presented. The technique is a generalized version of attenuated total reflectance (ATR) spectroscopy, that combines optical fibers and a Michelson interferometer spectrometer to make evanescent wave absorption measurements. Aluminum hydroxide is one of the major corrosion products of aluminum. Absorption spectra of powdered samples of aluminum corrosion, in the spectral region around three micrometers have been studied and compared with the spectra from pure powdered aluminum hydroxide. A chalcogenide optical fiber was used as an attenuated total reflectance (ATR) optical element. The same samples were …


The Anodic Dissolution Of Tungsten, James W. Johnson, Cheng-Hsiao Wu Jan 1971

The Anodic Dissolution Of Tungsten, James W. Johnson, Cheng-Hsiao Wu

Chemical and Biochemical Engineering Faculty Research & Creative Works

The anodic dissolution of tungsten was studied in H2SO4-K2SO4 solutions (pH = -2 to 2.5) and K2SO4-K2CO3-KOH solutions (pH = 11.5 to 14.5) at 25 C. Faradaic efficiency studies in basic solutions showed the metal to be oxidized to the +6 state. In acid solutions, a thick protective film of yellow WO3 was formed. Polarization curves possessed linear Tafel regions (slope ~ 2.3 RT/F) at potentials slightly more positive than the rest potentials. An anodic dissolution mechanism is proposed which involves a surface film …