bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of the End-of-Life (EOL) Content in High-Pressure Vacuum-Assisted Die Cast (HPVADC) Aural2 (AlSi10Mg) on Corrosion Behaviour
Authors: Ando Yuki , Kish Joey , Shankar Sumanth 
Published: November 2022

Al cast alloys are widely used in automotive applications due to their high strength-to-weight ratio. The castability of Al alloy is known to be excellent; the idea of implementing the End-of-Life (EOL) Al alloy parts to fabricate new Al alloys is determined to be feasible. In contrast, the fabrication of Al cast alloys with the EOL content increases the propensity of introducing the impurity element to the Al cast alloys. It is expected to affect the microstructure such as the distribution and morphology of intermetallic particles. The mechanical properties of those alloys, also known as the secondary alloys, are comparable to primary alloys, however, the corrosion behaviour of secondary alloys is not fully characterized and understood. It is anticipated that the corrosion behaviour is affected by the EOL content introduced to the Al cast alloys.
In this research, HPVADC Aural2 alloy with different EOL contents (0%, 40%, 75%, and 90%) are subjected to various electrochemical characterization techniques and microstructure characterization. Cyclic polarization measurements were conducted on both skin and core parts of the alloys. The breakdown potential (Eb) of the primary alloy was found to be the lowest, however, the potential difference between the breakdown (Eb) and repassivation (Er) of the primary alloy was significantly smaller than the secondary alloys. Potentiostatic polarization was also performed on both skin and core parts to observe the corrosion modes, and it was determined that both initiation and propagation corrosion modes were inter-granular/inter-dendritic corrosion. Galvanostatic polarization measurements were performed, and the behaviour of the potential responses differed between the primary and the secondary alloys, as well as the core and skin. Scanning Vibrating Electrode Technique (SVET) will be performed on the cross-section, skin, and core region to observe the local anodic/cathodic current density. The passive layer characteristics of each EOL alloy will be investigated by X-ray Photoelectron Spectroscopy (XPS). Microstructure analysis through Light Optical Microscope (LOM) and Scanning Electron Microscopy (SEM) was conducted. The distribution of Si eutectic and Fe-containing intermetallic particles on the secondary alloys was found to be different from the primary alloy; the mean size of intermetallic particles observed on the skin in the secondary alloys was higher than the primary alloy. No significant difference was observed at the core region in terms of intermetallic distribution. The morphology and chemistry of intermetallic particles will be further investigated with Energy Dispersive Spectroscopy (EDS).
This research is conducted to characterize the effect of EOL content on their microstructures which is essential to understand the corrosion behaviour of the secondary alloys, ultimately enhancing the utilization of EOL parts in the Al cast alloy manufacturing.
On the Nature of Critical Potentials for Aluminum Repassivation
Authors: Kiosidou Evangelia (Lila) , Srinivasan Jayendran , Noell Philip James , Schindelholz Eric John 
Published: November 2022

Repassivation (Erp) and pitting transition potential (Eptp)1,2 are considered critical parameters in aluminum pitting, because they have been associated with repassivation phenomena3,4. The physical meaning of Erp has long been well-established in the literature as the threshold between stable pitting and complete repassivation of the material5–7. The nature of Eptp, however, has not been thoroughly explained in the current literature apart from the primary assumption that it represents the commencement of repassivation4. Moreover, experimental investigation and evidence to expand this argument as well as to explore the relationship between these two potentials has been scarce4.
The present work aims to address these open questions with cyclic potentiodynamic polarization (CPP) and potentiostatic experiments conducted on high purity Al in NaCl. Repassivation trends at and below Eptp were explained based on the assumption of actively corroding fractions which were dependent on the applied potential. Morphological transformation was also observed during polarization as evidenced by electron microscopy and X-ray microtomography after the electrochemical tests. The observation of a distinct Erp separate from the Eptp during slow CPP scans was related to the charge passed and was hypothesized to be the net effect of the gradually decreasing actively corroding area at potentials below Eptp, which resulted in morphology that restricted mass transport out of the pits, which delayed complete repassivation. SNL is managed and operated by NTESS under DOE NNSA contract DE-NA0003525.

References

K. Nisancioglu and H. Holtan, Corrosion Science, 18, 1011–1023 (1978).

K. L. Moore, J. M. Sykes, and P. S. Grant, Corrosion Science, 50, 3233–3240 (2008).

S. T. Pride, J. R. Scully, and J. L. Hudson, J. Electrochem. Soc., 141, 3028 (1994).

M. Yasuda, F. Weinberg, and D. Tromans, J. Electrochem. Soc., 137, 3708 (1990).

A. Broli and H. Holtan, Corrosion Science, 13, 237–246 (1973).

G. S. Frankel, J. R. Scully, and C. V. Jahnes, J. Electrochem. Soc., 143, 1834 (1996).

G. S. Frankel, J. Electrochem. Soc., 145, 2186 (1998).
In-Service Corrosion Performance of Automotive AA7075 Sheet Alloy
Authors: Wang Shanshan , Piroteala Tudor , Ryan Kevin , Kamat Rajeev , Yuan Yudie 
Published: November 2022

Aluminum alloys offer higher specific strength than advanced high strength steels, making them preferred material choice for automotive light weighting. Among them, AA7075 sheet alloy offers significantly higher strength than 5xxx and 6xxx alloys and has been developed to provide high in-service strength for automotive structural applications. However, there is a need to understand the stress corrosion cracking (SCC) susceptibility of AA7075 under “in-service” conditions for the automotive market. Currently there are no commonly accepted corrosion testing specifications or evaluation criteria for AA7075 sheets among material suppliers and automotive original equipment manufacturers. Furthermore, there is a lack of in-service data to validate the accelerated laboratory exposure testing. In this study, in-service SCC performance of the AA7075 test coupons was evaluated by road exposure for a two-year period under harsh Canadian winters. The SCC specimens were loaded using four-point bending frames, and were investigated in various tempers and surface conditions (bare vs. e-coated). Overall, the road exposure results were consistent with the lab accelerated testing such as slow strain rate tensile testing in specific environments. Coating provided sufficient corrosion protection such that the stressed coupons survived after 2-year road exposure without reduction in strength. For bare metals, overaged T73 and in-service (T6+paint bake) tempers outperformed T6 temper. Localized corrosion of AA7075 sheets with various tempers was also studied using potentiodynamic polarization technique.
Acknowledgements: Dr. Danick Gallant, Aluminum Technology Center at National Research Council Canada; Kennesaw lab support in Novelis Global Research and Technology Center.
(Digital Presentation) Spark Plasma Sintering Fabrication of α/β Interface in Mg Alloys and Analysis of Corrosion Behavior
Authors: Shao Zheng , Nishimoto Masashi , Muto Izumi , Sugawara Yu 
Published: November 2022

In Mg alloys, corrosion behavior is known to be related to the microstructure. For example, AZ91D alloy contains an α matrix phase (Mg solid solution), β phases (Mg17Al12) and lamellar α+β microstructures. During the real-time in situ observation of the corrosion process under galvanostatic polarization, filiform corrosion proceeded along the outside of the β-phase (in lamellar α + β microstructure and along the α-mother phase[1]. However, the detailed mechanism of the initiation and growth of filiform corrosion is still unknown. An electrode area contains simplified α + β structure is needed to clarify the corrosion mechanism of Mg alloys. The fabrication of such specimen could be actualized by Spark Plasma Sintering (SPS).
The advantage of SPS is that it can produce specimens with high efficiency and few pores. The energy from the pulsed current, self-heating of the workpiece, and particle-to-particle discharge are the combined driving force for sintering. In recent years, many experiments have been reported on the fabrication and strength evaluation of pure Mg and Mg alloys. However, only a few studies have been conducted on the fabrication and corrosion resistance of different phases.
In this study, we attempted to fabricate the interface of β and α phases by SPS using pure Al powder and pure Mg powder and other materials. The characterization of different phases was carried out by XRD, EPMA and TEM. The corrosion behavior of the sintered specimens was then observed using an in-situ observation system during open circuit potential measurements. After measurements, the specimen surface was assessed using OM, AES, and FE-SEM.
When a 0.25 mm thick Mg sheet was surrounded by pure Al powder, the temperature was set at 420 °C and kept for 30 minutes, a uniform white microstructure was found to form around the Mg sheet. The thickness is about 50 µm. EDS maps and point analysis show that this phase consists a β-phase (Mg17Al12) on the Mg sheet side and Mg23Al30 on the Al powder side. The thickness of the β-phase did not change obviously when the sintering time was extended to 1 hour. Finally, a β phase with a thickness of about 100 μm could be fabricated by using a specimen assembly method of outer Al powder, intermediate layer Mg powder. Analysis of corrosion behavior was done with this specimen.

Z. Shao, M. Nishimoto, I. Muto, and Y. Sugawara, Corrosion Science, 192, 109834 (2021).
The Effect of [Cu(EDTA)]2− on Crevice Corrosion of Type 316L Stainless Steel
Authors: Aoyama Takahito , Kato Chiaki 
Published: November 2022

Alloyed Cu is known to inhibit the growth of pitting corrosion on stainless steels after pitting initiation. The Cu2+ dissolved from the stainless steel matrix acts as an inhibitor in acidic chloride environments which is formed in pits. The Cu2+ suppresses active dissolution rate inside the pits1. This suppression effect is supposed to be also effective for active dissolution which promotes crevice corrosion. Therefore, if it is possible to introduce Cu2+ to the inside of a crevice from the outside, introduced Cu2+ is supposed to inhibit crevice corrosion on stainless steel. However, diffusion of ions between inside and outside of the crevice is restricted by its geometry, and Cu2+ does not migrate to inside of a crevice according to the electroneutrality principle. [Cu (EDTA (ethylenediaminetetraacetic acid))] 2− is a chelated Cu2+ which has negative charge, and is expected to migrate to inside of a crevice from the outside by electrochemical migration. In addition, it is reported that Cu2+ in [Cu(EDTA)]2− could be easily substituted by Fe2+ in low pH2. Therefore, Cu2+ is considered to be introduced to the inside of the crevice as [Cu(EDTA)]2−, and to affect crevice corrosion of stainless steel. In this study, in situ observation of an inside of the crevice3 was performed to analyze the effect of [Cu(EDTA)]2− on crevice corrosion.
Type 316L stainless steel was used as specimen. The crevice corrosion tests were conducted in a flow cell3. 0.1 M NaCl or 0.1 M NaCl-10 mM [Cu(EDTA)]2− was flowed through the flow cell. The crevice was made by pressing the glass plate on the specimen surface. The specimen surface was perfused with 0.1 M NaCl before the glass plate was pressed. Therefore, inside of the crevice was filled with 0.1 M NaCl. The specimen was polarized at 0.35 V (vs. Ag/AgCl, Sat. KCl). After the crevice corrosion initiation, the different propagation morphology was observed between 2 conditions. In the case of 0.1 M NaCl, the gas bubbles were observed with corrosion propagation. On the other hand, little gas bubbles were observed in the case of 0.1 M NaCl-10 mM [Cu(EDTA)]2−. The gas bubbles observed in 0.1 M NaCl were considered to be H2 generated by the H+ reduction reaction inside the crevice. It was reported that the reduction reaction inside the crevice was changed by migrated anions which reacted with H+ inside the crevice3. Therefore, the results indicate [Cu(EDTA)]2− migrated to the inside of the crevice from the outside, and affected the crevice corrosion morphology.
References

T. Sourisseau, E. Chauveu, and B. Baroux, Corros. Sci., 47, 1097-1117(2005).

W. Guan, B. Zhang, S. Tian, and X. Zhao, Appl. Catal. B, 227, 252-257 (2018).

T. Aoyama, Y. Sugawara, I. Muto, and N. Hara, J. Electrochem. Soc., 166, C250-C260 (2019).
Influence of Metal Cation and Temperature on Localized Corrosion Behavior of Steels in Aqueous Environments
Authors: Sakairi Masatoshi , Shen Tong , Han Xiaole 
Published: November 2022

Steels are abundantly used in many areas because of their good formability and low price. Steels suffer from corrosion in aqueous environments with chloride ions. Corrosion of steels is also a serious problem for long-term usage of steel structures such as bridges and buildings. There are many studies focused on chloride ions. There are reports that metal cations have a tendency to inhibit the corrosion of steels in a chloride aqueous environment by forming a layer on the steel.
The other important factor for corrosion of steels in an aqueous environment is temperature. The corrosion rate of metal in cold regions is expected to slow because of low temperature. A recent study on atmospheric exposure tests carried out in different places in Hokkaido, it has elucidated that the corrosion rate in the cold region is the same as in the warm region.
However, it is not fully elucidated that temperature, especially below freezing point, and metal cations on corrosion behavior and distribution of active dissolution site. The purpose of this study is to investigate the influence of temperature and metal cations on thecorrosion behavior of steels.
Steel sheets of 15 x 20 mm and 20 x 20 mm were used as specimens. Three solutions of 0.1 mM ZnCl2, 0.5 mM ZnCl2 and 1.0 mM ZnCl2 were used for examination of the effect of metal cations, and 20 mass % NaCl solution was used for examination of effect of temperature. After the tests, the morphology of specimens was examined by optical microscope and scanning electron microscope.
After the wet/dry corrosion tests used 10 mL solutions droplets, corrosion products were formed on the specimens. The corrosion processes under NaCl and MgCl2 were similar. Yellow corrosion products were firstly observed in the solution during the wet period. In the case of under ZnCl2, after the formation of oxide layer on the specimens the corrosion proceeded in localized areas. The color of almost half area of the exposed surface was light, which might indicate less corrosion occurred in the area. The initial corrosion stage of steel preferred to form a brown area in the center of the droplet. There are no similar corrosion products thatcan be observed in comparison to the samples under MgCl2 and NaCl solutions.
A lot of corrosion products and localized corroded areas were formed on specimens after being immersed at 273 K, while less corrosion products and homogenously corroded surface were observed on specimens after being immersed at 293K.
The results indicated that corrosion morphology and preferentially corroded area were changed with the kind of metal cation and temperature.
Electrochemical Study of Pitting Corrosion of Corrosion Resistant Alloys in Supercritical CO2 Environment
Authors: Eslami Maryam , Wang Xi , Choi Yoon-Seok 
Published: November 2022

Various types of corrosion resistance alloys such as 13 Cr, Super 13 Cr, and duplex stainless steels are typically used in oil and gas and CO2 capture and storage applications, especially the injection section, where the pipeline could be exposed to aqueous phase and the risk of localized corrosion is of high concern. The composition of these materials is engineered to provide high corrosion-resistant properties. The operating conditions in the above-mentioned applications can include high CO2 pressure and high temperature leading to the “so-called” supercritical CO2 condition. Under the supercritical CO2 conditions, the pH of the aqueous phase in the system can be as low as pH ~ 3 buffered by the dissolved CO2. The environment can also contain high salinity, and therefore, the passive layer on the stainless steel might be locally damaged resulting in pitting corrosion. While there are numerous studies available on the localized corrosion of different stainless steels in chloride-containing aqueous environment, the number of studies in supercritical CO2 conditions is limited. The objective of this work is to understand the effect of supercritical CO2 on the localized corrosion mechanism of corrosion resistant alloys.
Three different types of corrosion resistant alloys (13 Cr, Super 13 Cr, and duplex stainless steel) are studied under CO2 pressure (0 to 14 MPa) and at high temperature (150˚C) in 5 wt.% NaCl solution. The experiments are conducted in a high-pressure autoclave system at a consistent initial pH for comparison. The electrochemical behavior and the pitting corrosion are studied using cyclic potentiodynamic polarization and potentiostatic measurements. The surface of each specimen is investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) before and after the electrochemical experiments to characterize the microstructural and localized corrosion features, respectively. All the tested materials show passive behavior under the conditions of the current study, however the pitting potential decreased in this order: duplex, Super 13 Cr and 13 Cr stainless steel.
Development of MoO3-Based Proton Batteries
Authors: Ikezawa Atsunori , Nishizawa Tadaaki , Koyama Yukinori , Arai Hajime 
Published: November 2022

Aqueous rocking chair batteries have attracted attention as highly safe and inexpensive secondary batteries. Lithium and sodium ions have mostly been used as the mobile ions, whereas proton systems with potentially the highest mobility have rarely been reported. Recently, research on proton batteries has been conducted using concentrated sulfuric acid solutions as the electrolyte that can assist high-rate performance.[1] Stability under concentrated acidic conditions is required for the electrode materials, as well as the capability of proton accommodation. MoO3 has been reported as a stable negative electrode material for aqueous proton batteries,[2] while few positive electrode materials are known except for bulky organic[3] and Prussian-blue materials[4]. For achieving high energy density and long life, oxide positive electrode materials are desirable. Here we propose the application of MoO3 as the positive electrode material by optimizing the operating composition range. The potential values shown below are all shown versus SHE (actually measured with Ag/AgCl).
MoO3 showed a discharge profile at around 0.5 V with the maximum capacity of ca. 100 mAh g-1, as shown in the figure. This potential is sufficiently more positive than the redox potential of protonated MoO3 of around -0.3 V as the negative electrode. With the aid of operando X-ray diffraction analysis, it turned out that the discharge regions at 0.5 V and 0.4 V are respectively associated with a biphasic transition of MoO3/phase I (ca. 0 < x < 0.3 in H
x
MoO3) and a single-phase reaction of phase I (ca. 0.3 < x < 0.5 in H
x
MoO3). Deep discharging beyond this range results in the coexistence of phase I and phase III (ca. 0.5 < x < 1.5 in H
x
MoO3) and the proton extraction from phase III leads to the formation of phase II or phase IIa with its discharging potential of 0.0 V. Structural calculation based on the density function theory is employed to clarify the origin of this irreversible phase transition behavior. Different proton sites between these phases seem to be responsible.
An aqueous proton battery with a 7 mol dm–3 sulfuric acid electrolyte was constructed with H-inserted MoO3 and MoO3as the negative and positive electrodes, respectively, and was successfully discharged and charged repeatedly, with the operating voltage of ca. 0.6 V, indicating the launch of aqueous proton battery composed of oxide active materials.

Reference
s
:

[1] J. Li, H. Yan, C. Xu, Y. Liu, X. Zhang, M. Xia, L. Zhang, J. Shu, Nano Energy, 89 (2021) 106400.
[2] X. Wang, Y. Xie, K. Tang, C. Wang, C. Yan, Angew. Chem. Int. Ed., 57 (2018) 11569.
[3] X. Wang, J. Zhou, W. Tang, Energy Storage Mater., 36 (2021) 1.
[4] X. Wu, J. J. Hong, W. Shin, L. Ma, T. Liu, X. Bi, Y. Yuan, Y. Qi, T. W. Surta, W. Huang, J. Neuefeind, T. Wu, P. A. Greaney, J. Lu, X. Ji, Nat. Energy, 4 (2019) 123.

Figure 1
Near Infrared Spectroscopy of Fission Products in Alkali Chloride Molten Salt – Structural Interpretation and Analytical Use
Authors: Moon Jeremy , Chidambaram Dev 
Published: November 2022

Advanced nuclear technologies using high-temperature molten salts are poised to increase the efficiency, flexibility, and acceptability of nuclear energy. To realize these advances, additional understanding of the chemistry and thermochemical and thermophysical properties of the molten salt mixtures is required. Additionally, methods to rapidly and non-destructively monitor and determine the concentration and chemistry of actinides and fission products must be developed. Electronic and vibrational spectroscopy are promising methods to both interpret the structure and speciation of dissolved species in molten salts and to determine concentrations of species of interest. We have determined the molar absorbance coefficients of selected absorbance features for several lanthanides of interest in the ultraviolet, visible, and near infrared ranges and show that some NIR absorbance features, which were previously neglected as a means of concentration determination, are analytically useful. In fact, these NIR absorbance features may have advantages over UV and visible range features for concentration determination in industrial systems. Additionally, we will present our analysis of the effects of the coordination environment on lanthanide electronic structure and transitions, yielding insight into the chemistry and coordination of these elements in molten alkali halide mixtures, which is crucial for understanding the corrosion issues in these salts amongst other requirements.
Acknowledgement:
This research is being performed using funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs under award DE-NE0008889 and the US Nuclear Regulatory Commission (USNRC) under contract 31310018M0032. Dr. Kenny Osborne and Ms. Nancy Hebron-Isreal serve as the program managers for the DOE and NRC awards, respectively.
This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. DGE-1447692. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation, the U.S. Department of Energy, or the United States Government.