Aluminum WrapUp
Volume 9, Issue 3
Nov 2021- Fall/Winter Issue
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Anthony Petters joined the Secat Team in July as a Materials Engineer. He was previously an Intern with 3M Ceradyne. Tony’s work includes inspecting samples provided by customers for either qualification purposes or analyze failure modes. He is also assisting with the internal 6XXX series alloy research project, where he prepares the base materials for the new alloy and then casts the new alloy. Anthony has played 3 instruments before (clarinet, oboe, and steel drums), and he is currently learning guitar. He also loves water skiing.
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Abraham Duenas is the newest member of Secat, joining the team two months ago as the Mexico Sales Representative. Prior to Secat, he worked as the key account manager for an automotive company that manufactured car arm rests. Abraham’ s responsibilities include locating and contacting potential new customers and introducing them to Secat. Abraham tells us; “My first job coming out of school was as translator for a Canadian company, I’m a very fast translator. “
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You can learn more about us on Secat’s website here.
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What’s New in Training
In 2022, Secat will continue to offer a variety of training opportunities with virtual and in person options.
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FEATURED CAPABILITIES
K-Alpha X-ray Photoelectron Spectrometer (XPS) System
Compact XPS for high-performance surface analysis of materials ranging from metals to polymers
Brief introduction
- Sampling depth 5-10 nm from the top surface
- Elemental quantification for all elements Li and above, except H and He
- Quantitative chemical information
- Detection limit ~ 0.1 Atomic%
- Composition profiles for thin films and interfaces when combined with ion profiling
- Elemental and chemical state surface distribution when used in imaging mode
Basic theory
X-ray photoelectron spectroscopy (XPS), also known as electron spectroscopy for chemical analysis (ESCA), relies upon Einstein’s photoelectric effect, in which an X-ray photon removes an electron from an atom or molecule. The kinetic energy of that electron depends upon the photon energy and the energy required to remove the electron (the binding energy) according to the equation:
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…where the kinetic energy of the emitted electron, Ek, is measured.
Typically, a monochromatic X-ray source of a known energy, e.g., Al Kα radiation at 1486.6 eV, is used in the excitation. h is Planck’s constant, ν is the photon’s wavelength, and W is the spectrometer work function, which is also a known value that corrects for the few electron volts of energy given up by a photoelectron as it is absorbed by the detector. This allows the binding energy, EB, of the emergent electron to be easily calculated from the equation above. Since the binding energy is a characteristic of the chemical environment of the parent atom, it is possible to quantify not only the elemental composition of the surface, but also the chemical state.
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Technology
Ultra-high vacuum (UHV) is required to increase photoelectron path length and maintain sample cleanliness. The X-ray source for excitation of photoelectrons is usually Al or Mg Kα radiation. A concentric hemispherical electron analyzer is used for measuring the kinetic energy of the emitted photoelectrons, with channeltrons or channelplates for detection. Systems are typically configured with both charge compensation system for insulator analysis and a profiling source for depth composition analysis.
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Applications
XPS is used for the analysis of solid surfaces, thin films, and interfaces. The technique is considered to be standardless, requiring no external calibration to obtain quantified results. It also requires little or no sample preparation. The surface represents a discontinuity between one phase and another. The physical and chemical properties of the surface are, therefore, different from those of the bulk materials. These differences affect the topmost atomic layer of the materials to a large extent because a surface atom is not surrounded by atoms on all sides. This results in the surface atom having a bonding potential, which makes it more reactive than atoms in the bulk.
The number of application areas in which XPS is used is extensive, encompassing both academic and industrial research and development, QA/QC, and contract laboratories. These areas include:
- Measuring surface contaminations
- Ultra-thin film and oxide thickness measurements
- Characterization of surface defects, stains, and dislocations
- Measuring effect of surface preparation treatments
- Composition of powders and fibers
- Chemical characterization of plasma-modified polymer materials
- Measurement of coating thickness and conformity
- Composition depth profiling for multilayer and interface analysis
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The Thermo Scientific K-Alpha™ X-ray Photoelectron Spectrometer (XPS) System brings a new approach to surface analysis. Focused on delivering high-quality results using a streamlined workflow, the K-Alpha XPS System makes XPS operation simple and intuitive, with no sacrifice in terms of performance or capabilities.
Key features and applications:
- Simple sample loading: The sample holder is as large as 60×60 mm, and capable of handling samples up to 20 mm in thickness. Multiple samples, failed components, or specimens with stains can be processed by XPS over various time frames.
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- High-performance X-ray source: The X-ray monochromator allows selection of analysis area from 50 µm to 400 µm in 5 µm steps, fitting it to the feature of interest to maximize the signal.
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- Sample viewing: Bring sample features into focus with the K-Alpha XPS System’s patented optical viewing system and XPS SnapMap, which helps you pinpoint areas of interest quickly.
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- Insulator analysis: The patented dual-beam flood source couples low-energy ion beams with very low energy electrons (less than 1 eV) to prevent sample charging during analysis, which eliminates the need, in most cases, for charge referencing.
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- Point analysis: Fast spectra survey scan for elemental identification and quantification
- Elemental ID:
- Which elements are present?
- Can detect all elements except for H
- Elemental quantification:
- How much of an element is present?
- Detection limit >0.05% for most elements
- Allows determination of stoichiometry
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- High resolution spectra for chemical state analysis
- Chemical state quantification:
- Oxidation states
- Chemical environment
- Functional groups
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- Mapping – Stained aluminum part
- Problem: Discoloration is apparent on an aluminum assembly
- Solution: Identify elemental and chemical composition of discolored areas by Quantitative chemical state mapping, the area indicated inside the green rectangle was mapped. The XPS data can be displayed as an overlay on the optical image, allowing easy visualization of the location of chemical states.
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Go beyond the surface with the EX06 ion source. Automated source optimization and gas handling ensure excellent performance and experimental reproducibility.
The following figures shows depth profiling a sample with a polymer film coating on an aluminum substrate. It can be clearly seen all critical elements change with the etch depth, and especially in the vicinity of the interface between polymer film and Al substrate.
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Sources:
Secat data:
Figures 6, 10, and 13.
Visit us at www.secat.net and check out all that we have to offer!
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Person of Interest
David Leezer, Midea RAC Products R&D Engineer
David Leezer is a R&D Engineer for Midea’s North American Room Air Conditioning team with prior experience at GE Appliances as a Platform Manager and Design Engineer on products like the Zoneline PTAC and GeoSpring Heat Pump Water Heater. David has 12+ years in the appliance industry with the majority of his career developing and testing heat exchangers and air conditioning systems. He has extensive experience in aluminum evaporator corrosion test development and validation working to find ways to increase the robustness of aluminum material in HVAC applications. David holds a Bachelor of Science in Mechanical Engineering and a Masters of Engineering in Mechanical Engineering from University of Louisville’s J.B. Speed School of Engineering.
Give us a quick overview of your job.
I am a Research and Development engineer for Midea’s North American Room Air Conditioning team which covers everything from dehumidifiers to window air conditioners to Packaged Terminal Air Conditioners (PTAC). My role is to work with our team in identifying the need of the US consumer, translating that to a technical need and then working with our China team in creating an end product. This can include anything from new features to a more robust system for specific environmental needs or quality improvements creating a better product.
What are some things that happen for you in a typical day at work?
Since the room AC business is seasonal, my typical day varies throughout the year. During our selling season, typical days involve communication in the morning with our team in China to discuss customer feedback and quality improvements to better meet consumer needs. I’ll then use the rest of the day to review any returned units as well as begin developing new features for future products. During the non-selling season, I’ll work more heavily on R&D specifically new product design and prototype development as well as working with the China team to ensure various product improvements are implemented.
How does your job impact the markets you serve?
This role is unique as an R&D engineer by allowing me to have direct feedback and interaction with both customers (stores, distributors) and consumers to understand their individual needs and wants. This allows our team to be involved in the full product cycle life from the very beginning to the very end thus creating products that better meet customer and consumer needs. The changes and products I help develop are being sold right in my local store which is rewarding to see.
How do you interact with Secat, Inc. and how does the relationship benefit you?
Secat helps our team with the metallurgical analysis of various materials, corrosion testing and guidance on corrosion protection for our products. This is immensely beneficial since most of these capabilities are located at our facilities in China where the corrosion environment is much different than the US and it’s more difficult to constantly check. Having Secat’s facility located close to our research center allows for us to tap into local labs and facilities, but also local expertise familiar with the US environment that our AC products are going to experience. This allows us to create a more robust product for the US market.
Tell us something about yourself (outside of the industry) that people may not know.
I’ve been happily married for 11 years and proudly hang my hat on the fact that I have four daughters (ages from 11 months to 8 years) – needless to say I’m full-on girl dad! I’m active with my church volunteering with High Schoolers (which only reminds me how old I’m getting!). My favorite hobby is anything automotive and anything racing, but have really got into Formula 1. I’ve got a 1993 Mustang that I plan to teach my girls how to work on and drive as they get older which they already love to help with today.
#HeLovesAluminum
#WeLoveAluminum
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Tech Talk
Aluminum Processing Research at Lehigh University Loewy Institute
The Loewy Institute at Lehigh University continues the research and educational mission of the Institute for Metal Forming. Processing of aluminum alloys is a primary focus at the Lowey Institute where research has traditionally focused on process development and optimization, tooling design, microstructural response to parameters in deformation processing and powder metallurgy technologies. Our tools include a range of scientific instruments and techniques such as physical modeling using laboratory metal forming equipment and Gleeble thermo-mechanical simulator, numerical simulation FEM package Deform® to study deformation processes supported by extensive capabilities of our light optical microscopy and electron optical microscopy material characterization techniques. Our 3D Printing studies are performed in-house on a Renishaw 400 printer. This multi-tool approach allows us to tackle various scientific and engineering challenges. Our team consist of graduate students supported by visiting scientists and postdocs, undergraduate students as well as faculty from different fields, primarily Materials and Mechanical Engineering Departments. For the Secat newsletter, we discuss three projects on aluminum related technology: solid state recycling, selective laser melting of aluminum alloys, and development of process models for the continuous rotary extrusion process.
Mahsa Navidirad, doctoral candidate in Materials Science and Engineering (MS&E) department, is studying solid state recycling. Traditional recycling of aluminum alloys involves re-melting and casting of aluminum scraps. The recycling process is far less expensive and energy intensive than extracting metal from bauxite through the electrolysis process. This problem is especially difficult to deal with when fine metal scrap is re-melted due to high surface area and huge amount of dross formed. To overcome this problem associated with the re-melting, an alternative solid-state recycling approach has been proposed in which fine scrap and chips are converted to either final or semifinal products through various severe plastic deformation techniques. However, as the aluminum chips are naturally covered by an oxide layer, yielding a product with optimum mechanical properties remains a main challenge for this process. In fact, the brittle oxide layer acts as a barrier to solid state bonding. In our current project, a roll bonding process has been carried out as a solid-state plastic deformation technique for bonding aluminum strips, which were specially anodized for the purpose of aluminum oxide observation and analysis. The process has been conducted under different process conditions to evaluate not only the effect of each parameter on the bonding quality but also to study the fundamental mechanism of bonding through breaking the oxide layer and creating metal-to-metal contact. The physical experiment and materials characterization efforts are additionally supported by the Finite Element Method analysis of the roll bonding process led by Dr. John Plumeri.
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Emerging technologies such as additive manufacturing are also studied in the Loewy Institute. Michael Pires, doctoral candidate in the MS&E department, melt dynamics of different aluminum alloys with potential applications in the aviation, automobile, and aerospace industries. This project explores a laser-based powder fusion (LBPF) technology of additive manufacturing (AM), known as selective laser melting (SLM), to manufacture components with commercially available aluminum alloy powder. The silicon rich 4xxx series alloy, AlSi10Mg (AA4046), has been studied extensively in literature and is known to print extremely well; this was chosen as our base alloy for comparison throughout the project. Although AM is a reliable method for 4xxx series alloys, better mechanical properties are necessary for evolving applications. 6xxx series aluminum alloys consisting of Al-Mg-Si, in this case AA6061, have been previously shown in literature to provide the necessary mechanical properties, but may lack the ability to print well. This project investigates the optimal SLM parameters needed to 3D print AA6061 components with near net density in the as-built condition. Adjusting the parameters effects the thermal history of the final component, controlling its microstructure and resultant mechanical performance. As shown in Figure 3, few microstructural defects exist for the 4xxx series alloy (left) and a high number of defects, such as porosity and cracking, exist for the 6xxx series (right). Porosity and cracking can drastically deteriorate the mechanical properties of a component. With proper control of the parameters, the goal is to reduce or eliminate the formation of these microstructural defects.
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Dr. Nijenthan Rajendran is using commercial software Deform® to analyze the mechanics of the continuous rotary extrusion (CRE) process in collaboration with Monika Mitka from the Institute for Non-Ferrous Metals in Skawina, Poland who is a doctoral candidate at AGH University of Science and Technology in Krakow. Dr. Rajendran developed a process model for the CRE process during his doctoral studies and applied it to analysis of metal flow conditions leading to extrusion tool design. The physical experiments of CRE of AA6063 were performed by our research partners in Poland. However, the limitation and the expenses of the physical experiments were overcome with the numerical process simulations. This approach reduces the cost and time as we can run any number of simulation trials with different process parameter that we are interested in and most importantly we can study and analyze what is happening within the deformation chamber at any point of time. In our work we developed the numerical process model using numerical software DEFORM 3D®. The developed process model was validated by comparing the simulation results with the experimental findings as shown in Figure 4. Finally, we applied the validated process model to study the effect of tooling design modifications in the CRE deformation chamber on metal flow of AA6063 aluminum alloy.
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Aluminum Art
Historically Speaking
The early history of aluminum – (19th Century) finds its novelty being translated into many forms of artwork. Before the metal was mass produced, it was considered rare and precious and it was incorporated into, among other things, jewelry and decorative items. Emperor Napoleon III reserved a prized set of aluminum cutlery for special guests at banquets. (Less favored guests used gold knives and forks.) The book, Aluminum by Design, traces the history of aluminum from its beginnings through modern day as an inspiration and medium for artists, designers, architects and engineers.
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Do you have a piece of Aluminum Art you’d like to share? Contact us at info@secat.net
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