Engineering Commons^™

Intergranular And Pitting Corrosion Mechanisms Of Sensitized Aluminum Alloy Aa5083, Clayton Egleston

Williams Honors College, Honors Research Projects

The motivation and objectives of this project is to examine the mechanisms of intergranular corrosion (IGC) and pitting corrosion of sensitized AA5083. In this regard, different characterization techniques were used, including optical analysis of microstructure, cyclic potentiodynamic polarization with Tafel fitting, electrochemical impedance spectroscopy with electrical equivalent circuit (EEC) fitting, and potentiostatic current transient monitoring. The transition from IGC to pitting corrosion occurs when the grain boundaries become saturated with the β-phase (Mg₂Al₃). It was found that AA5083 becomes more vulnerable to pitting corrosion as the degree of sensitization increases.

Electrochemical Impedance Spectroscopy Analysis Of Corrosion Of Reinforcing Steel In Fly Ash Mortar By Means Of Transmission Line Modeling, Padraig Stack

Williams Honors College, Honors Research Projects

Electrochemical impedance spectroscopy (EIS) is an important non-destructive tool that allows for a deeper understanding of the electrochemical processes and mechanisms occurring in an electrochemical cell. Equivalent electrical circuits (EECs) are used to model the impedance data into electrical components, such as resistors and capacitors, on a circuit. Current potentiostat offers software packages that can analyze the frequency response, but the software only supports “simple” EEC that can be written as fixed electrical components in some combination of series and parallel. Park and Macdonald propose a transmission line model (TLM) that does not use lumped-element models, instead, the values of …

Austenitic, Duplex, And Lean Duplex Stainless Steel Critical Pitting Temperature In Simulated Concrete Environment, Bobby Giebel

Williams Honors College, Honors Research Projects

In this work, the critical pitting temperature (CPT) will be observed for a selection of austenitic (316LN and 24100) and duplex (2205), and lean duplex (2304, 2001) stainless steels in simulated concrete pore solution. To study the influence of temperature on the pitting stability of the stainless steels, three temperatures were tested: 25oC, 45oC, and 65oC for cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS). Electrochemical properties of the interfaces we studied via EIS analysis. Kinetics were studied via CPP testing. To reveal the critical pitting temperature of the stainless steels, cyclic thermammetry was used. Characterization of the pits …

Increasing The Corrosion Protection Of Aisi 1008 Carbon Steel By Surface Treatment With Unmodified And Benzotriazole Modified Sol-Gel Films, Shane Thomas Kelliher

Williams Honors College, Honors Research Projects

The corrosion performance of sol-gel coated AISI 1008 carbon steel was investigated in 3.5 wt% NaCl solutions of pH 7, 9, and 12 using electrochemical measurements. A corrosion inhibitor, benzotriazole (BTA) was added to the sol-gel mixture and tested as a second, modified sol-gel coating. Sol-gel films adhered evenly to metal samples and were characterized by FTIR spectroscopy. Electrochemical Impedance Spectroscopy (EIS) showed an increase in polarization resistance from blank to sol-gel coated samples (600-18,800,000 ohms). Cyclic polarization (CPP) curves showed positive hysteresis loops for blank and unmodified sol-gel coated samples which increased at high pH following the backward potential …

Rust Preventative Spray Varnish Verification And Nozzle Development, Dakota Snyder, Collin Whitely, Stephen Patrick, William Mccullough

Williams Honors College, Honors Research Projects

This document details the research and selection of five rust preventative spray varnishes that were to be tested. These varnishes are known as the five materials. The materials underwent rust testing and in-depth analysis to see which protects against rust the best. In addition, the document reports on the construction of a prototype self-contained, automated spray varnishing unit.

Testing The Effectiveness Of Reflective "Cool" Pigments, Ashleigh Carpenter

Williams Honors College, Honors Research Projects

This project is an exploration of reflective "cooling" pigments used in coatings for the exterior of a structure in order to control the temperature inside. The pigments reflect sunlight to reduce the heating effect inside a structure. While the project will include the synthesis and testing of these pigments, the focus will be on the design and construction of an apparatus to test the effectiveness of these pigments. An apparatus will be constructed with a heat source and two structures of identical dimensions. The set-up will allow for the temperature of the inside of the structures to be recorded at …

Controlled Release Of Corrosion Inhibitors: Zinc And Magnesium Containing Sodium Chromate, Andrew Thomas

Williams Honors College, Honors Research Projects

Corrosion can be combated by multiple methods, where the primary purpose is to minimize degradation of metal surfaces. Corrosion inhibitors are one of the most effective methods of corrosion protection. Inhibitors are substances that minimize corrosion in aggressive environments, with only a low concentration required. The inhibitors are chemically adsorbed on the surface of the metal and a protective thin film is formed . The mechanism of the inhibitors could be described as anodic, cathodic, or a mix of the two. Anodic inhibitors, also known as passivation inhibitors, alter an anode reaction. Corrosion potential of the metal is shifted to …

Benefits Of Aluminum: Comparing The Common Materials In The Bar Grating Industry, Joanthan Geiser

Williams Honors College, Honors Research Projects

The main aim of this project is to study the wholistic behavior of the 6xxx series of aluminum for use in the bar grating industry for a waste water treatment environment. This project will study the comparison of certain aluminum 6xxx series alloys to steel, stainless steel, and glass fiber-reinforced plastic. While comparing these materials, it will look at the mechanical properties such as modulus of elasticity, yield strength, and ultimate tensile strength. In addition, the available corrosion test of the 6xxx series aluminum alloys will be examined to find a generalization of the corrosion behavior for this series. A …

Cataloging The Degree Of Sensitization Via Electrochemical Reactivation For Studying The Corrosion Behavior Of Inconel 718, Austenitic, And Duplex Stainless Steels, Bradley Lynes

Williams Honors College, Honors Research Projects

Corrosion resistant materials can be expensive, but usually reduce the life cycle cost of metallic assets. However, negligent sensitization of these materials can lead to aggressive, intergranular corrosion. Using the methodology of the double loop electrochemical potentiokinetic reactivation (DL-EPR), this project investigates different steel reinforced bars and Inconel to determine the degree of sensitization after a heat treatment of 900°C for 2 hours. The purpose of this research is to validate and determine the appropriate test parameters for performing further DL-EPR test in the future. Additionally, the kinetics observed for each sample during the DL-EPR test will be analyzed and …

Stress Corrosion Cracking Of Stainless-Steel Reinforced Concrete, Nathan Frye

Williams Honors College, Honors Research Projects

Stainless steel rebar is one of the most corrosion resistant reinforcing methods for concrete structures. Stainless steel is used for its chromium content and its ability to form a passive oxide corrosion resistant layer. The presence of chloride is one of the largest attackers of this passive film and able to penetrate concrete due to its porous characteristics. This study evaluates the mechanical performance of different stainless steels relative to their changing environments. It is expected that as chloride concentration values increase, mechanical properties will decrease. This will be tested by performing tensile tests on stainless steel rebar sample that …

Development Of Cardanol-Based Epoxy Coating, Nicholas Pottschmidt

Williams Honors College, Honors Research Projects

The purpose of this project was to determine the suitability of cardanol glycidyl ether (CGE) as a substitute for trimethylolpropane triglycidyl ether (TMPGE) as the reactive diluent in epoxy coatings. CGE may be a naturally-derived alternative to TMPGE, which is a commonly-used petroleum-derived reactive diluent. Epoxy coatings were formulated with CGE replacing increasing amounts of TMPGE in the formulation. Corrosion protection provided by the coatings was evaluated with electrochemical impedance spectroscopy (EIS). Mechanical properties of the coatings (hardness, flexibility, adhesion, and impact resistance) were evaluated with applicable ASTM standards.

EIS results revealed the coating formulated with only CGE had superior …

The Influence Of Organic Pigments On Coating Properties, Sarah Medeiros

Williams Honors College, Honors Research Projects

Abstract

The purpose of this project was to identify the qualities of two synthesized organic pigments added to a coating. These high-performance pigments were benzodipyrrolidone and benzodifuranone, which are π-conjugated monomers. These pigments were each formulated into two different pigment concentrations and compared with a control that had no pigment. This project is limited by time constraints and the number of variables that can be tested in that time. Performance testing was conducted to evaluate the qualities of these coatings. The results demonstrated that the coatings were reproducible and most tests had results that were equal to or exceeded the …

Evaluation Of Silane-Doped Epoxy Coatings For Resisting Aluminum Corrosion By Oxalic Acid, An A. Niger Metabolite, Alex Pica

Williams Honors College, Honors Research Projects

The goal of this study was to investigate whether silane-doped epoxy coatings are capable of preventing corrosion of aluminum alloy 2024-T3 by oxalic acid, one of the primary metabolites of the fungus Aspergillus Niger. Previous research suggested the success of these types of coatings at preventing AA 2024-T3 corrosion in saline solutions, and this study was meant to build on those findings by investigating the efficacy of the coating in an acidic environment.

Each coating was applied to an AA 2024-T3 coupon by dissolving the epoxy and varying amounts of 3-aminopropyltriethoxysilane in acetone and then dripping the solution onto …

Effects Of Corrosion Inhibitor On The Corrosion Behavior Of Low Carbon Steel In Co2 Environment, Michael Harris

Williams Honors College, Honors Research Projects

The effectiveness of Benzalkonium chloride (C14) as a corrosion inhibitor for mild steel in an aqueous CO₂ environment was studied for dual use. It is a known biocide and currently untested corrosion inhibitor. Potentiodynamic polarization was used to determine the anodic and cathodic reaction kinetics through analysis of the potentiodynamic curves and the corrosion current densities. Electrochemical impedance spectroscopy (EIS) was utilized to analyze the surface characteristics through analysis of the Nyquist and Bode plots. C1010 and C1018 mild steel were tested in a 200mL jacketed Gamery cell, and purged with CO₂ (99.9%). Temperature effects were studied and …

Pitting Corrosion Of 410 Stainless Steel In Hcl Solutions, Paul D. Krell

Williams Honors College, Honors Research Projects

410 stainless steel (SS) is a material used in HCl services, such as distillation column trays in oil refineries. Unlike other alloys, however, the oil refining industry lacks a good reference for the corrosion rate of 410 SS at the varying HCl concentrations and temperatures the material might experience as trays in crude unit distillation columns. The goal of this project is to fill that knowledge gap. The corrosion behavior of 410 SS in HCl environments of pH 0.50, 1.25, 2.25, 3.25, and 4.25 at temperatures of 38, 52, 79, and 93°C was investigated using several methods. Cyclic potentiodynamic polarization …

Corrosion Resistance Of Silane Coatings On Aluminum And Magnesium Alloys, John Demopoulos

Williams Honors College, Honors Research Projects

The purpose of this project was to increase the corrosion resistance of aluminum and magnesium alloys by coating the coupons with a silane on the surface. Four different silanes: 3-aminopropyltriethoxysilane (APTES), Bis(triethoxysilylpropyl)amine (Bis), (Heptadecafluoro-1,1,2,2-tetrahydrodecyl)trichlorosilane (FTS), and (Heptadecafluoro-1,1,2,2-tetrahydrodecyl)triethoxysilane (non Cl FTS) will be used and compared to see which silane would give the best corrosion resistance. Each silane solution was coated on the coupons by using a solution method in which the coupon was submerged for 24 hours and then thermally cured for another 24 hours. Once the coating was applied, the water contact angle and the thickness of the coating …

Evaluation Of Epoxy Coatings For Protecting Aluminum Alloy 2024 From Corrosion Caused By Aspergillus Niger, Kamshat Dukenbaeva

Williams Honors College, Honors Research Projects

The aim of this study was to assess the potentials of using epoxy coatings for the prevention of fungus-induced corrosion. The metal specimen of interest was the aluminum alloy AA 2024-T3. The main intent was to evaluate the behavior of the organic acid producing fungus, Aspergillus niger (A. niger), towards the epoxy-coated aluminum. Two different types of epoxy coatings were used: a two-part resin and a commercially-available Rust-Oleum Specialty Appliance Epoxy. Due to challenges encountered throughout the length of the project and time constraints, limited quantitative data was obtained. However, from optical and visual data it can be concluded that …

Effect Of Sintering Temperature On Microstructure, Corrosion Behavior, And Hardness Of Nanocrystalline Al-5at.%Ni And Al-5at.%V Alloys, Matthew G. Wachowiak

Williams Honors College, Honors Research Projects

The purpose of this project was to investigate thermal stability of high energy ball milled Al-5at.%Ni and Al-5at.%V alloys. Characterization was done by analyzing grain size and solid solubility. Samples were created using high energy ball milling, cold compaction to 3 GPa, and sintering from 100 °C to 500 °C at 100 °C increments, as well 450 °C and 614 °C. Microstructure, mechanical properties, and corrosion properties were determined using scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction, hardness testing, and cyclic potentiodynamic polarization. Vickers hardness of Al-5at.%Ni decreased with increasing temperature. For Al-at.%V, hardness increased with sintering temperature …

Galvanic Corrosion On Monel K-500 And 1018 Carbon Steel Couple, John K. Nnyanzi

Williams Honors College, Honors Research Projects

The purpose of this research project was to evaluate galvanic damage on 1018 Carbon Steel coupled to Monel K-500 at varying rotation speeds on a rotating cylinder electrode in an aerated solution of ASTM artificial seawater. The work in this project is and attempt to study corrosion behavior for a Monel fastener coupled to a Carbon Steel plate. Polarization curves of each material at different rotation speeds were created to predict the corrosion behavior for a galvanic couple of Carbon Steel and Monel. The Potentiodynamic sweeps predict an increase in the corrosion current density for the galvanic couple when then …

Stress Corrosion Cracking Evaluation Of Carbon Steel In Biodiesel And The Effect Of Ultrasonic Nanocrystal Surface Modification (Unsm) On 304 Stainless Steel, Josh Geyer

Williams Honors College, Honors Research Projects

The project that was performed was stress corrosion cracking (SSC) of carbon steel in biodiesel, petroleum diesel and a mixture. The project also included the effect of Ultrasonic Nanocrystal Surface Modification (UNSM) on 304 stainless steel. It included the assembly of a slow strain rate (SSR) machine and carrying out testing using the SSR machine. The assembly of the machine will require purchasing and building a stand to house the electrical equipment which includes the computer, actuator control panel and the actuator power supply. The assembly will also include designing and purchasing the connections to connect the actuator to the …

Oxidation Resistance Of Nanocrystalline 316l Stainless Steel Processed By High Pressure Torsion, Kevin J. Meisner

Williams Honors College, Honors Research Projects

High Pressure Torsion (HPT) is a materials processing method used to refine the grain size of metallic materials through the application of simultaneous axial and torsional strain. HPT is reported to result in nanocrystalline structure, which the current scientific literature suggests may improve the high temperature oxidation resistance by enhancing diffusion of solutes, particularly Cr, to the surface to form a protective external oxide scale. If oxidation resistance is improved, this possibly allows the use of 316L in oxidizing environments where more expensive alloys are typically used. However, the influence of grain refinement to nanoscale on various properties have been …

Passivation And Potential Fluctuation Of Az31b Alloy In Alkaline Environments, Ana C. Bacco

Williams Honors College, Honors Research Projects

Magnesium (Mg) alloys are used in many industries because of their distinctive properties, but their high chemical reactivity and poor oxide film protection make them inferior. This project focused on investigating the effects of secondary phases and intermetallic particles (IMPs) on the corrosion behavior of AZ31B Mg alloy. The test solution was chloride free NaOH with varying pH levels between 10-14, as well as testing under deaerated conditions. The open circuit potential (OCP) measurements using AZ31B in static NaOH solutions showed potential fluctuation between approximately -1.6 V_SCE (active state) and -0.4 V_SCE (passive state) during the 24-h immersion. …

The Examination Of Stress Corrosion Cracking In High Strength Carbon Steel Through Combined Mechanical-Electrochemical Testing, Jacob Sines

Williams Honors College, Honors Research Projects

Through the analysis of materials and environments seen in industry a better understanding of the fundamentals behind degradation mechanisms can be observed. The scope of this project was to better understand the fundamentals behind the degradation of high strength pipeline steels in a lab setting to simulate an environment seen in industry. Specifically the degradation mechanisms of high and nearly neutral pH stress corrosion cracking were examined in environments that simulated oil and gas pipelines buried in soil. Experimentation was carried out utilizing X65 carbon steel specimen, a Gamry potentiostat, a CORTEST proof ring, a CORTEST slow strain rate machine, …