Monthly Student Spotlight: Membership Mondays
December 2022: Marshall Yang
This month, our #sossmembershipmonday features Marshall Yang, now a Postdoctoral Associate at Western University, working with Dr. Yolanda Hedberg in the Department of Chemistry on N-heterocyclic carbenes (NHCs)-based coatings. He recently completed his PhD thesis in the Department of Chemical and Biochemical Engineering.
PhD project title: Development of Anti-corrosive Polyester Powder Coatings
My research focused on UV-resistant polyester/TGIC powder coatings for anti-corrosive application. Powder coatings are green solutions to replace the environmentally unfriendly liquid paints. Three types of additives and functional filler, namely zinc phosphate with passivation effect, zinc powder with sacrificial anode effect, and two nanoclays with barrier effect were incorporated into the coatings to enhance the anti-corrosive performance. The anti-corrosive properties were evaluated by electrochemical techniques and neutral salt spray tests. The combined effects of the additives with a filler barium sulfate were also investigated. The effect of the film thickness was studied and optimized by the statistical method Mixture Design.
The additives and functional filler significantly improved the anti-corrosive performance of the coatings, e.g., Rp values of the nanoclay-containing coatings had increases of two orders of magnitude from electrochemical measurements. The salt spray resistance of zinc-rich coatings with 80% zinc increased from 500 h to 3000 h. The self-repairing capabilities of the coatings with zinc phosphate and nanoclays were confirmed by electrochemical impedance spectroscopy, and the mechanisms of zinc-rich powder coatings were investigated in detail. Neutral salt spray test gave different results from electrochemical methods for the optimal dosages of zinc phosphate and nanoclays. The discrepancy was caused by different features of the two tests, such that the electrochemical tests probe the function of intact coatings, whereas salt spray measures only the corrosion spreading from the scribe.
The surface qualities and mechanical properties of the coatings were evaluated as per applicable ASTM standards. Other characterization techniques, including SEM/EDS, confocal laser scanning microscopy, Raman spectroscopy, XRD, and microCT, etc., were utilized for analyzing coating structures and identifying the passivation layer, corrosion products, and the underlying mechanisms.
Check out some select publications, here:
https://doi.org/10.3390/coatings12020217
https://doi.org/10.3390/pr10091853
https://doi.org/10.3390/coatings9020110
https://doi.org/10.1021/acsami.0c16582
https://doi.org/10.1016/j.cej.2022.135925
https://doi.org/10.3390/powders1040015
https://doi.org/10.1039/9781788012997-00368
Figure 1. Schematic of two different exposure conditions and damage mechanisms arising in (a) electrochemical tests and (b) neutral salt spray tests.
Figure 2. (a–d) EIS spectra, (e) conventional and (f) newly developed equivalent electrical circuits for a powder coating containing 8% zinc phosphate additive.
Figure 3. (a–e) Confocal maps and (f) surface roughness (Sa) values of polyester/TGIC powder coatings with different zinc contents.
November 2022: Elliott Asare
It's the first Monday of November, so we have another #SOSSMembershipMonday for you, featuring Elliott Asare from McMaster University!
Project Title: Developing Innovative Surface Modifications for Corrosion Control in Hydrothermal Liquefaction of Biomass
Multiple industries (municipal waste, pulp and paper, etc.) are in search of a cost-effective organic by-product processing method. Direct conversion of biomass into marketable bio-oil serves as an ideal alternative to impractical disposal methods. The most promising route for biomass conversion is hydrothermal liquefaction (HTL).
The HTL processing environments are inherently corrosive consisting of: hot pressurized water (250-374°C and 4-22 MPa), caustic catalyst, aggressive anions, and organic acids. Thus, candidate alloys require suitable general corrosion and stress corrosion cracking (SCC) resistance. The objective of this research is to determine the effect of surface treatments, alloy selection, and innovating coating technologies on the corrosion control of candidate materials in HTL conversion. The corrosion assessment consists of: static autoclaves tests, electrochemical tests, slow strain rate testing (SSRT), and high temperature U-bend testing.
Austenitic and ferritic steels are currently considered for HTL implementation. Austenitic steels offer excellent general corrosion resistance but are costly and susceptible to SCC failure mechanisms. Ferritic steels are considered as a more cost-effective SCC resistant alternative to austenitic steels. Our static autoclave tests determined that austenitic SS304 produced minimal corrosion in comparison with ferritic SS409. Coating application (electroplated and chromized) administered to SS409 significantly improved general corrosion resistance past that of the austenitic steels. Our U-bend tests determined that SS304 was susceptible to sulphur assisted cracking. The ferritic SS409 coated samples did not produce any cracking.
Figure 1: Preliminary SCC assessments were conducted using the SSRT apparatus at room temperature.
Figure 2: SSRT fracture surface of chromized SS409 after exposure to simulated HTL conversion environment at room temperature
Figure 3: Cross-sectional TEM/EDS micrograph and maps of SS304 after high temperature U-bend tests revealing an SCC crack
September 2022: Ekrupe Kaur
After a break to host our annual symposium in August, we are back with another #sossmembershipmonday!
This month, we are featuring Ekrupe Kaur, studying under the supervision of Dr. Yolanda Hedberg and Dr. Mark Biesinger.
Project Title: Method Development for Chromium Speciation in Solid Materials using X-ray Photoelectron Spectroscopy.
My research focuses on method development and systematic detection of Cr(VI) on surfaces using X-ray Photoelectron Spectroscopy (XPS). Good method development of Cr(VI) species using XPS has been hindered by a lack of understanding of the complicated spectral peak shape, peak binding energy shifts and spectral overlaps for organo and sulfate containing Cr compounds. This project will investigate solid-phase speciation of multiple matrices/samples contaminated with Cr. One compound I am studying is called basic chromium sulfate (BCS) which is a tanning agent used to tan approximately 90% of all leather. Under certain weathering conditions the Cr(III) from this compound can oxidize to Cr(VI). This is of particular concern because Cr(VI) is toxic and a known carcinogen to humans in contact with it. Therefore, understanding the surface of chromium-tanned leather and accurately quantifying the amount of Cr(III) and Cr(VI) on the surface is of utmost importance. The results from this study will ultimately aid in the legislative side that aims to monitor acceptable amounts of Cr(VI) released from leather. In addition, systematic detection of chromium in its stable oxidation states (Cr(VI) and Cr(III)) will aid in chemical speciation and analysis of future projects in other solid surface
systems such as cement.
Figure 1: The high-resolution Cr 2p3/2 spectrum of the leather tanning agent, BCS (Basic Chromium Sulfate), fit with 4 peaks.
Figure 2: The Kratos AXIS Supra (front) and Kratos AXIS Nova (back) at Surface Science Western.
July 2022: Udo Okoro
We are halfway through 2022, and ready to share some more fantastic work on #sossmembershipmonday! This month, we are highlighting Udo Okoro from Queen's University!
Project Title: Mechanistic understanding of the passivity breakdown of steam generator (SG) materials
As part of the solutions to achieving the 2050 Net-Zero carbon emissions, nuclear energy, which generates about 10% of the world's electricity, should be part of the energy mix (along with solar, wind, and hydrothermal). Therefore, the safe operation of the existing CANDU fleet and potential upcoming small modular reactor technologies requires a mechanistic understanding of the various degradation mechanisms of the structural materials.
My research investigates the effect of impurities, such as lead, sulfates, or magnetite buildup, on the passivity of steam generator materials (Alloy 600, 690, and 800). Due to local boiling, the impurities can be present at the heat transfer crevice between the steam generator tube, tube support plates, and tube sheet. With the help of a static autoclave, we will study the passivity breakdown and stress corrosion cracking mechanism of steam generator materials in a high-temperature, high-pressure aqueous environment. To assist in the characterization of the corrosion mechanism, the materials will be characterized using advanced microscopy techniques.
Studies have been performed on the above materials in environments with various possible impurities. The various materials and environment combinations have shown unique corrosion and cracking mechanisms. For example, previous studies have shown the presence of sulfates at the crack/metal interface of alloy 800 in acidic sulfur-containing environments. The presence of sulfur at the crack/metal interface affected the overall oxide passivity, accelerating metal atom dissolution.
Figure: High-resolution EDX elemental maps from a mature environmentally assisted crack in an Alloy 800 blunt-notched tensile specimen after crack initiation testing at 280 °C in 0.5 mol/kg sulfate solution at pH280°C 3.
June 2022: Thao Do
Summer is here, and so is another #SOSSMembershipMonday! Thao Do supervised by Dr. J. Clara Wren of the RAMPS group at Western is our June feature student! Check out his work below!
Project Title: Laser Ablation Removal of Metal Oxides from Reactor Alloys
In nuclear reactors, a large fraction of radioactivity is concentrated in the surface oxides that have grown during corrosion while in service. Stripping the radio-contaminated surface oxides from nuclear reactor alloys would allow the volumes of low- and intermediate-level radioactive metallic wastes to be reduced. Chemical methods are effective in removing surface oxides but generate large volumes of the decontaminant liquid wastes. If the main concern is not the extension of their services lives, non-chemical methods such as stripping using a laser or focused ion beam can provide an efficient means of removal of radioactive surface oxides without generating additional wastes. Laser ablation provides the greatest flexibility of deployment, the possibility of safety remote operation, at relatively low cost.
My research focuses on the development and optimization of a process for surface decontamination of metallic wastes using an ytterbium-doped fiber laser (1064 nm). The development of this decontamination methodology for radioactively contaminated metals will contribute significantly to innovative technologies for nuclear decommissioning and decontamination efforts.
Figure: Laser cleaning of a corroded carbon steel pipe
May 2022: Martin Badley
It's May! And that means it's time for another #sossmembershipmonday, featuring Martin Badley from Western University, supervised by Dr. Jamie Noel.
Project Title: Investigating the corrosion and dissolution mechanism of CANDU uranium dioxide
Uranium dioxide is the primary fuel source for CANDU nuclear reactors. The used fuel removed from a reactor remains a potential health and safety hazard unless managed properly. The preferred option for used fuel disposal employs a series of engineered barriers to contain and isolate the used fuel essentially indefinitely. To ensure the safe management of used fuel, it is necessary to consider the consequences of barrier failure by investigating the possible degradation processes of the used fuel.
My research uses electrochemical experiments to perform accelerated degradation experiments to further our understanding of how the used nuclear fuel behaves if exposed to groundwater in a failed container scenario. Under such conditions the used fuel can act as a barrier itself, containing radionuclides from release to the surrounding environment. By understanding the degradation processes of the uranium dioxide waste form, we can help ensure the safety of people and the environment.
April 2022: saman nikpour
It's the first Monday of April and that means its time for another #SOSSMembershipMonday, featuring Saman Nikpour from Dr. Yolanda Hedberg's group at Western University! Keep reading to find out how Saman is studying the corrosion of biomedical alloys!
Project Title: Investigations of corrosion modes of biomedical alloys of relevance for joint replacement
Titanium alloys such as commercially pure titanium (CP-Ti) and Ti-6Al-4V (6 wt.% Al and 4 wt% V) are appropriate for dental implants and total joint replacements, including hip and knee, as they can offer high corrosion resistance. Due to their susceptibility to wear, they are not usually used for surfaces exposed to wear, such as bearing surfaces. The chemical environment in the human body is important. Interactions between proteins and metal ions and the formed oxide layer can alter the corrosion behavior of implants during their service life. The way implants are fabricated is also crucial. Increasingly, additive manufacturing (AM) is utilized for biomedical implants. Some of the AM companies, moreover, apply a standardized passivation process through immersion in nitric, ASTM F86-13, acid to increase the corrosion resistance of AMed implants. This project aims at understanding whether surface passivation after manufacturing AM Ti-6Al-V has any effect on corrosion and metal release under benign physiological conditions and harsh conditions, simulating a crevice environment.
march 2022: sara filice
Today is the first Monday of March! And what better way to celebrate than to share another #SOSSMembershipMonday - this month we are featuring Sara Filice from McMaster University!
Project Title: Towards the Development of Hydrogen Induced Cracking Resistant X70 Grade Pipeline Steel
Pipelines are extensively used for the transportation of oil and gas, where either can contain relatively high levels of hydrogen sulfide. When exposed to such an environment, pipeline steel can undergo corrosion processes such as hydrogen induced cracking and stress corrosion cracking, which can lead to in-service failure of pipelines. The steel microstructure is widely recognized as a critical factor affecting these corrosion processes. Therefore, a fundamental understanding of the links between steel microstructure and these failure mechanisms is necessary so that control measures can be put into place.
Her research focuses on characterizing the hydrogen trapping capacity of niobium precipitate particles; utilizing heat treatments to vary and determine the relative effects of size, size distribution, and volume fraction of niobium precipitates. Hydrogen trapping characterization is completed through thermal desorption spectroscopy, and an evaluation of the extent of hydrogen embrittlement is completed through the use of slow strain rate mechanical testing with and without in-situ hydrogen charging.
February 2022: Hunter Feltham
It's time for our February SOSS #MembershipMonday! This month, we are learning about Hunter Feltham's research at Western University!
Project Title: Probing the Oxide Growth Mechanism of Thin Film Titanium Oxide
Bone implants are a necessity in today’s medical landscape. Titanium implants are nearly ideal as they have minimum side effects inside your body. When considering corrosion, for instance, the rusting of your car; titanium corrodes differently. Instead of flaking off like rust, titanium forms a protecting layer which prevents further corrosion.
This research uses the Tandetron accelerator at Western University to look at the movement of these atoms to understand formation of the protecting layer on an atomic level. Using this, safer and longer lasting generations of titanium implants can be intelligently designed to more effectively interact with the human body’s environment.
Figure: In-situ sample setup to simulate the protection layer formation of titanium in the environment of the human body while measuring electrochemistry, under the beam of the Tandetron (Same size and shape as a hockey puck!)
january 2022: HOoman Gholamzadeh
It's the first Monday of 2022! And what better way to start the year, than to highlight another student from the NACE SOSS for #SOSSMembershipMonday, featuring Hooman Gholamzadeh from Queen's University!
Project title: The role of Dealloying as a Precursor to Stress Corrosion SCC of Ni-Fe-Cr Alloys in Caustic Environments
Refurbishment and life extension of the currently operating nuclear power plants necessitate an understanding of all possible degradation mechanisms of the structural materials. Despite their resistance to general and localized corrosion, Fe- and Ni-Based alloys have been shown to suffer from environmentally assisted cracking. Alloy 800 CANDU steam generator tubing material, for instance, has shown very good in-service performance for decades. However, laboratory experiments have shown susceptibility of this material to dealloying and SCC in hot caustic environments where a nanoporous dealloyed layer acts as a precursor to SCC by a proposed film-induced cleavage mechanism. My research focuses on dealloying and SCC of Alloy 800 in boiling caustic environments. I study the SCC mechanism of Alloy 800 using electrochemistry techniques, micro and macro mechanical tests, and different characterization techniques. Our results indicate a correlation between dealloying/porosity formation and cracking of Alloy 800. The nano-scale analysis confirms cracking by cleavage mechanism.
Figure: The figure shows a STEM image of cracks initiating from a nanoporous dealloyed surface film after exposure of Alloy 800 U-Bend to boiling caustic solution along with EELS elemental maps of the surface film.
November 2021: Claire TUlly
It's the first of the month and that means it is time for a new student highlight! Check out what Claire Tully is studying at Western University!
Project Title: Investigating Microbially Influenced Corrosion of Copper in Compacted Bentonite Clay
Canada’s plan for the safe disposal of nuclear waste relies on long-term storage of the used fuel in an engineered multi-barrier system, contained within a deep geological repository. Within this system’s design, the used fuel is stored in copper-coated steel containers and placed 500 m below the surface in compacted bentonite clay. Within the clay, microbial activity may result in microbially influenced corrosion of the copper canister. My research focuses on the mitigation of the microbially influenced corrosion by controlling the compaction density of the bentonite clay surrounding the copper material.
Some of our experiments are placed 500 meters below ground in boreholes located in Ignace, Ontario! The exposure of canister material, compacted in bentonite clay, to Canadian groundwater will illustrate how the canister material will fare in repository conditions.
Image: NWMO Borehole drilling in Ignace, Ontario
July 2021: Jamie jewer
The NACE SOSS is very excited to highlight our very first Membership Monday! On the first Monday of the month, we will highlight a student in our section who is doing amazing research. Each month will feature a student from a different university.
For our first #SOSSMembershipMonday, check out what Jaime Jewer is getting up to at McMaster University!
Project Title: The Effect of Direct Hot Press Forming on the Electrochemical Properties of Next Generation Zn-Coated Press Hardenable Steels
Automotive parts are often formed by a process called hot press forming. In this process, the galvanized steel is heated to 900°C, and then stamped with water cooled dies. This can damage the galvanized coating and impact its ability to provide cathodic corrosion resistance to the part. In my research, I look at the coating after hot stamping and use electrochemistry to determine if corrosion resistance is provided on galvanized prototype grades of steel after hot press forming.
Pictured here are the U-shape galvanized part after hot press forming and a cross-sectional image of the coating at the corner of the part. Note all the cracks in the coating.
October 2021: Isabella McDonald
Its time again for our #SOSSMembershipMonday! This month, we are featuring Isabella McDonald from McMaster University!
Project Title: Corrosion Performance of High Temperature Alloys in Molten Salt Mixtures for Next Generation Energy Systems
Molten chloride salts have been proposed to be used as the primary coolant in molten salt reactors, and as the heat transfer fluid in concentrated solar power plants in next generation energy system design. The corrosive properties of molten chloride salts make it challenging to find appropriate structural materials for plant/system realization.
In my research, I am investigating two corrosion mitigation methods to determine the relative corrosion performance of high temperature alloys in molten chloride salt mixtures: (1) chemical purification of salt mixture using a Mg sacrificial anode and (2) developing a protective oxide layer on the surface of alloys during pre-oxidation treatment. These corrosion inhibitors are studied in combination with each other to determine the relative corrosion performance of three high temperature alloys (a silica former, an alumina former, and a chromia former).
September 2021: Baian Almusned
Our NACE SOSS #SOSSMembershipMonday is here again after a Labour Day Holiday Monday! This month, we are featuring Baian Almusned from Western University!
Project Title: Electrodialysis Study of Metal Cations
Heavy metal ion capture has a number of applications including wastewater treatment, leach mining, and radioactive metal capture in the event of a spill. Research on heavy metal ion capture is ongoing with the objective of establishing the most efficient and selective capture method.
For my research, electrodialysis, which is defined as the movement of charged species through an ion-exchange membrane upon the application of an electric field, is investigated for its capabilities to capture and remove metal ion contaminants from water. The ion exchange membrane installed in the electrodialysis unit affects the removal efficiency of the process. Due to a lack of available ion-selective membranes, a new class of phosphorus-based polymers, known as CapturePhos, were developed at Western University. CapturePhos will be tested in order to characterize their electrochemical behaviour as electrodialysis membranes. A four-compartment electrochemical cell is employed for the electrochemical experiments (attached figure). Surface analytical techniques such as infrared (IR) spectroscopy are utilized to examine the membrane pre- and post-experimentations. Moreover, analytical techniques such as ultraviolet-visible (UV-Vis) spectroscopy and inductively-coupled plasma mass spectrometry (ICP-MS) are employed to analyze the metal ion concentration in solutions. This research will advance wastewater treatment methods as well as set the foundation for the capture of radioactive contaminants.
August 2021: Adil Shaik
It's finally #SOSSMembershipMonday again! This month we are featuring Adil Shaik from Queen's University!
Project Title: The nanoscale microstructure and mechanics of the oxide formed on Zr-2.5Nb alloy exposed to high-temperature water
Nuclear energy is one of the most technology-ready, low-carbon energy sources, alongside hydropower. In 2020, Nuclear power supplied ~2600 terawatt-hours of electricity, accounting to 10% of the world’s electricity production. To meet the increasing demand of electricity with the growing population, nuclear power has the potential to make a substantial impact, while still lowering greenhouse gas emissions.
According to the International Atomic Energy Agency (IAEA) there were 443 operating nuclear power plants in the world, with an additional 54 under construction, with a total capacity of 57441 MW(e). In all these reactor designs Zirconium (Zr) alloys are being used as for in-core components or as cladding material for nuclear fuel. The outer surface of fuel rods/cladding are exposed to 280 to 320 °C high temperature water, resulting in oxidation of the Zr alloy. In my research, I use transmission electron microscopy (TEM) to characterize the nanoscale defects in the oxide/metal due to radiation and understand the degradation mechanism in these alloys.
Figure: TEM Fresnel image at metal-oxide interface (Δf = ±650 nm) showing the distribution of nano-porosity in white contrast and cracks, highlighted with red color arrows.
December 2021: Des Williams
IIt's the last month of this year! December is here, and so is another #SOSSMembershipMonday! Check out what Des Williams at UofT is doing!
Project Title: Investigating Corrosion in Nuclear Steam Generator Materials
As the world transitions away from carbon-based forms of energy, nuclear power is re-emerging as an excellent candidate to meet baseline energy requirements. However, the aggressive chemistries that occur in these systems can induce localized material failure. This necessitates a thorough examination of nuclear materials in industry-relevant chemistries, such that the limitations of these materials may be well understood.
My research focuses on the mechanisms of corrosion of nuclear steam generator materials in secondary side chemistries. This work includes materials processing, electrochemical experimentation, and advanced nano-scale characterization. I hope to contribute to the development of nuclear energy through research of nuclear materials, and through teaching.
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