bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assessing Concurrent Uniform Corrosion of Aluminum Alloys As a Function of Temperature, pH, Time, and Chloride Ion Concentration
Authors: Huang I-Wen 
Published: February 2020

One of the greatest challenges for aircraft maintenance is localized corrosion induced fatigue and cracking, which is induced by aluminum alloys susceptibility to aggressive environment. Although pit growth kinetics was thoroughly investigated and nicely modeled by power law, the uniform corrosion impact on pit growth kinetics was ignored in the past, and therefore resulted in pit growth deviation from the ideal power law as indicated in a preliminary result. Uniform corrosion dissolved the surface material and thus induced reference plane recession and pit depth reduction. This non-trivial difference was proved to have a significant influence on pit growth modelling especially in high pH conditions.
In this work, temperature and pH influence on uniform corrosion of 2024-T3, 6061-T6, and 7075-T6 aluminum alloys were reported through the free immersion test method. Extensive results performed in various pH (3 to 10), chloride concentration (0.01M to 1M), and temperatures (20⁰C to 80⁰C) from up to 1 month is reported to mimic real applications. A comparison with the weight loss experiment was demonstrated to provide a quantitative significance of pitting and uniform corrosion, respectively. Severity of uniform corrosion were measured and versus various pH, temperature, time, and chloride concentration. The key finding in this work was that uniform corrosion rate is oxygen-dependent with a dynamic influence of passivation. Therefore, to identify the contribution of oxygen and passivation (as affected by pH and temperature), experimental approaches including electrochemical impedance spectroscopy (EIS) and cathodic polarization were utilized. Furthermore, TEM images and electron diffraction were performed to assess the structure and morphology of the protective corrosion product driven by temperature. In addition, the Artificial Neural Network (ANN) modelling was employed to analyze the data obtained. A statistic-based model is able to recognize corrosion behavior pattern versus various conditions, therefore a prediction model can be generated according to the environmental inputs.
In summary, the ultimate goal of this study is to suggest an effective maintenance for high value DoD and industrial assets according to an experiment-based prediction model and to understand the impact of different environmental parameters. In this study, a successful uniform corrosion predictive model was developed within specified conditions, which has a significant modification over pit depth growth. Therefore, a predictive model based on lab experimental data is applicable and an efficient low cost maintenance is doable.
Silicon Effects on the Corrosion of Ferritic and Austenitic Chromia Forming Alloys in Wet and Dry CO2
Authors: Nguyen Thuan Dinh , Zhang Jianqiang , Young David John 
Published: February 2020

Model alloys of Fe-9Cr, Fe-20Cr and Fe-20Ni-20Cr (wt.%) with Si (0.1, 0.2 and 0.5%) were reacted isothermally in dry Ar-20CO2 gas at 818 oC. Silicon-free Fe-9Cr formed thick scales of FeO and FeCr2O4, Fe-20Cr formed thin scales of Cr2O3 alone, and Fe-20Ni-20Cr formed Fe3O4, FeCr2O4 and FeNi3. Silicon additions suppressed formation of iron oxides on Fe-9Cr and Fe-20Cr-20Ni, and dramatically slowed oxidation of all alloys. Scales on 0.2Si-alloys consisted of an outer layer of Cr2O3 and an inner layer of amorphous SiO2. Internal precipitation of chromium-rich carbides took place in all undoped alloys, but was suppressed in Si-bearing alloys. Wagner’s theory of alloy depletion is shown to provide a successful description of these phenomena.
Addition of water vapour to the gas makes it much more corrosive. All silicon-free alloys underwent breakaway corrosion, developing thick iron-rich oxide scales and internal carbide precipitates. Silicon additions to Fe-9Cr had no detectable effect on reaction in wet gas, but were beneficial in the higher chromium alloys. Silicon additions substantially improved both oxidation and carburisation resistance in wet CO2, by forming a layer of silica beneath the chromia scale.
In both wet and dry gases, the silica layer acted as a barrier to carbon entry, and slowed outward metal diffusion, thus slowing scaling rates. Silicon-bearing austenitic alloys underwent scale spallation on cooling from reaction in wet gas, but not after reaction in dry CO2. No spallation was observed for ferritic alloys after reaction in either wet or dry CO2. The contributions of thermal and growth stresses to spallation, and of growth stresses to the onset of breakaway are discussed.
Hot Corrosion of SiC/BN/SiC Composites
Authors: Opila Elizabeth J. , Hagan Joseph 
Published: February 2020

SiC fiber-reinforced SiC matrix composites with a BN interphase (SiC/BN/SiC) are proposed for hot-section turbine engine applications. NaCl ingested into the engine in marine environments can react with sulfur impurities present in fuel forming molten sodium sulfate deposits resulting in hot corrosion. Hot corrosion of bulk SiC has been investigated, however, the effects of BN on SiC corrosion, as well as an understanding of hot corrosion resistance of SiC fibers and SiC matrix materials produced by different processing routes has not been elucidated.
In this study, Na2SO4-induced hot corrosion of model materials (i.e. bulk CVD or Hexoloy SiC with thin BN surface films) and SiC/BN/SiC composites was characterized in furnace studies at temperatures between 900 and 1150°C, for times up to 96 hours, and in O2 with 2.5 or 1000 ppm SO2. Na2SO4 was applied to the surface of coupons prior to furnace exposure. After exposure, the amount of corrosion was determined from weight change measurements. Corrosion products were characterized by Scanning Electron Microscopy, Energy Dispersive Spectroscopy, and dissolution followed by Inductively Coupled Plasma Optical Emission Spectroscopy. Thin film BN appeared to increase the hot corrosion attack of the model materials. The composites exhibited more severe hot corrosion than the model materials, especially in matrix areas with initial porosity. Sylramic fibers underwent more attack than Hi-Nicalon-S fibers.
Ceramic matrix composites were also exposed in a Mach 0.3 Burner Rig at 950°C for times of 24 and 45 hours. Simulated seawater (NaCl in deionized H2O) was injected into the burner rig, reacted with sulfur in the fuel to form Na2SO4 (8ppm) to induce hot corrosion. Severe hot corrosion was observed under these conditions. Microstructural and compositional characterization of the corrosion products is underway.
Finally, solubility of relevant oxides in sodium sulfate will be determined as a function of Na2O activity at 900°C to elucidate the SO2 and SO3 partial pressure dependence of hot corrosion of silica- and boria- forming materials.
SAM Assisted Nickel-Boron Electroless Metallization of PDMS
Authors: Molazemhosseini Alireza , Ieffa Simona , Vena Pasquale , Magagnin Luca 
Published: February 2020

Today, rapidly growing range of applications has a critical need for electronic systems, which cannot be made through rigid wafer-based technology. These applications include health-monitoring devices like electrochemical and strain biosensors. The key properties for these devices are bendability and stretchability [1-3]. As intrinsically flexible/stretchable materials have poor electrical performance, the dominant fabrication strategy is to exploit the flexibility of a polymer along with the electrical conductivity of a metal film. In this study, all-wet metallization of polydimethylsiloxane (PDMS) was carried out through Nickel-Boron (NiB) electroless deposition process. Self-assembled monolayers (SAM) of n-(2-aminoethyl) 3-aminopropyl-trimethoxysilane (AEAPTMS) was used to improve the metal thin film adhesion. PDMS surface modification was achieved by sodium hydroxide (1M) immersion for 24h. The modified surface was then silanized by a 0.02% v/v toluene based solution and later activated by a solution of palladium chloride. Water contact angle (WCA) examinations of PDMS surface revealed a significant decrease from 107° for the native surface to less than 50° after surface modification. Surface roughness changes were examined by atomic force microscopy (AFM) before and after each step of surface modification, silanization and metallization. Glow discharge optical emission spectroscopy (GDOES) confirmed the presence of the deposited layers together with the activated interface. Scanning electron microscopy (SEM) observations of PDMS/NiB interface indicated no detachment of NiB film for the silanized samples and significant detachment for non-silanized ones. Results of micro-scratch tests showed a 36% increase in the interface critical normal load of failure for the silanized sample compared to non-silanized one. Samples with three lines of NiB on PDMS (each line with 5mm width and 20mm length) were prepared to act as a flexible electrochemical sensor (Fig. 1). According to cyclic voltammetry results for a scan range of -1 to 1 mV, the presence of 500 and 1000 ppm ethanol in KOH solution (0.5M) were successfully detected.
References

A. J. Bandodkar, V. W. S. Hung, W. Jia, G. Valdés-Ramírez, J. R. Windmiller, A. G. Martinez, J. Ramírez, G. Chan, K. Kerman and J. Wang. 2013, Analyst., 138, 123.

J. T. Muth, D. M. Vogt, R. L. Truby, Y. Mengüç, D. B. Kolesky, R. J. Wood and J. A. Lewis. 2014, Adv. Mater., 26, 6307–6312.

W. Jia, A. J. Bandodkar, G. Valdés-Ramírez, J. R. Windmiller, Z. Yang, J. Ramírez, G. Chan and J. Wang. 2013, Anal. Chem., 85 (14), 6553–6560.

Figure 1
Microvia and through-Hole Filling By Electroplating for Electronic Circuit Fabrication
Authors: Dow Wei-Ping 
Published: February 2020

Electronic products, such as computers, smart phones, laptops and so on, need chips to perform their functions. These chips have many devices, which need to be integrated and connected with each other. To expand the functions of electronic products, more MOS have not met the requirement yet compared with more chips. Therefore, the concept of three-dimensional (3D) chip stacking packaging is proposed. To meet high density interconnection (HDI), through silicon vias (TSVs), through glass vias (TGVs) used as conducting channels of chip stacking need to be fully filled with metal (e.g., copper or nickel-tungsten alloy), and microvia and through hole designed in IC packaging substrates and printed circuit boards (PCBs) need to be fully filled with copper as well. These filling plating technologies have similar process steps but their feature size is totally different.1-11 Herein, we will review these process steps and propose novel filling plating process steps and technologies, including highly selective microvia filling without copper deposition on the outside plane surface, direct through hole filling without usage of a conducting template, TSV filling using CoWP as a barrier layer and electroless copper as a seed layer, TSV filling using reduced graphene oxide (rGO) as barrier and seed layers, TSV filling without copper but rGO combining with NiW alloy, TGV filling using electroless copper as a seed layer and direct pattern copper electroplating onto a glass wafer by using Al-doped ZnO (AZO) as an adhesive and conducting layer.
References:
1. W.-P. Dow and H.-H. Chen, Circuit World 30 (3), 33-36 (2004).
2. W.-P. Dow, H.-S. Huang, M.-Y. Yen and H.-C. Huang, Journal of The Electrochemical Society 152 (6), C425-C434 (2005).
3. W.-P. Dow, M.-Y. Yen, W.-B. Lin and S.-W. Ho, Journal of The Electrochemical Society 152 (11), C769-C775 (2005).
4. W.-P. Dow, H.-H. Chen, M.-Y. Yen, W.-H. Chen, K.-H. Hsu, P.-Y. Chuang, H. Ishizuka, N. Sakagawa and R. Kimizuka, Journal of The Electrochemical Society 155 (12), D750-D757 (2008).
5. W.-P. Dow, M.-Y. Yen, S.-Z. Liao, Y.-D. Chiu and H.-C. Huang, Electrochimica Acta 53 (28), 8228-8237 (2008).
6. W.-P. Dow, Y.-D. Chiu and M.-Y. Yen, Journal of The Electrochemical Society 156 (4), D155-D167 (2009).
7. W.-P. Dow, C.-C. Li, Y.-C. Su, S.-P. Shen, C.-C. Huang, C. Lee, B. Hsu and S. Hsu, Electrochimica Acta 54 (24), 5894-5901 (2009).
8. W.-P. Dow, C.-W. Lu, J.-Y. Lin and F.-C. Hsu, Electrochemical and Solid-State Letters 14 (6), D63-D67 (2011).
9. Y.-T. Lin, M.-L. Wang, C.-F. Hsu, W.-P. Dow, S.-M. Lin and J.-J. Yang, Journal of The Electrochemical Society 160 (12), D3149-D3153 (2013).
10. S.-P. Shen, W.-H. Chen, W.-P. Dow, T. Kamitamari, E. Cheng, J.-Y. Lin and W.-C. Chang, Microelectronic Engineering 105, 25-30 (2013).
11. J.-J. Yan, L.-C. Chang, C.-W. Lu and W.-P. Dow, Electrochimica Acta 109 (0), 1-12 (2013).
Smart Polymers for Future Damascene Applications: Combining Bottom-up and Levelling Capabilities
Authors: Nguyen Hai , Stricker Florian , Lechner David , Furrer Julien , Grimaudo Valentine , Moreno-García Pavel , Riedo Andreas , Neuland Maike , Tulej Marek , Wurz Peter , Broekmann Peter 
Published: February 2020

Classical additive concepts for the metallization of trenches and vias (Damascene applications) make use of a combination of polymeric suppressors (polyaklylene glycols, PAGs) and their specific antagonists (SPS). Their interplay is intended to regulate the desired bottom-up fill process. Typically, a leveler additive is added to the plating bath as a third additive component which is meant to avoid undesired overplating after the successful superfill.
In this contribution we discuss so-called hybrid polymers which comprise electrochemical characteristics of the PAG suppressors and classical leveler additives. Feature fill experiments demonstrate that bottom-up fill and leveling can indeed be achieved by using one single hybrid polymer component when combined with the SPS. Prototypical model additives showing these hybrid characteristics are polymerizates of epichlorohydrin and imidazole (Imep). Antagonistic Imep/SPS interactions required for the bottom-up fill are observed in particular at low (nominal) current densities whereas synergistic Imep/SPS interactions needed for leveling are dominant higher (nominal) current densities.
Copper films electrodeposited in the presence of an intact Imep leveler ensemble are essentially contamination-free. To probe the contamination level depth profiling experiments with sub-nm depth resolution were carried using a new femto-second laser ablation set-up coupled with a reflectron TOF mass spectrometer. This approach allows a true quantification of the contaminants which actually accumulate at the grain boundaries of the electrodeposited copper films.
Utilizing Inhibitor Molecules in Low Temperature CVD to Control Thin Film Conformality, Nucleation, and Surface Morphology
Authors: Abelson John Robert 
Published: February 2020

When performed at substrate temperatures < 300°C, the growth of thin films by chemical vapor deposition can be strongly inhibited by the reversible adsorption of precursor, byproduct, or neutral molecule species on the active surface. The system-dependent microscopic mechanisms include site blocking, associative desorption of precursor, or competitive adsorption. Under extreme site blocking conditions, the reaction probability of arriving precursor molecules drops as low as 10-6 per wall collision, a value that affords extremely conformal growth in deep features with aspect ratio > 100:1. The surface roughness is exceptionally low due to the smoothing effect of precursor re-emission, which mitigates the ‘shadowing’ effect of peaks in the local surface morphology. For precursor molecules that lack the vapor pressure or adsorption enthalpy to reach such values, we add a neutral molecule ‘inhibitor’ to enhance site blocking. This approach converts a ‘non-conformal’ precursor into one that provides good step coverage in features with aspect ratio ~ 10:1.
We derive, based on the diffusion-reaction equation, a conformal zone diagram that predicts regimes of highly conformal CVD as a function of precursor pressure, substrate temperature and feature aspect ratio.
We show that an inhibitor molecule can be used to control the film nucleation kinetics. There are two regimes depending on whether the inhibitor molecule binds more strongly to the film material than to the bare substrate surface, or vice versa, such that the equilibrium coverage of inhibitor is large only on the more strongly binding surface. For strong binding to the film, the density of small nuclei is enhanced, which affords an ultra-smooth film; we give the example of HfB2 growth on SiO2 using NH3 as the inhibitor. Conversely, when the inhibitor slows the nucleation rate, the deposit consists the sparse distribution of islands in a narrow size distribution that may be useful in photonic or catalytic applications; we give the example of Cu growth using VTMS as the inhibitor. Variants of the latter also afford highly selective growth, e.g., Cu deposition on a pre-existing metal line with essentially zero Cu nucleation on neighboring oxide.
Finally, we describe two methods to afford superconformal growth, meaning that the film growth rate increases with depth in a feature of aspect ratio between 10:1 and 25:1. These utilize either a high sticking probability, consumable inhibitor, such as atomic H or N produced by a remote plasma source, or an intrinsic rate competition between two reactants. Superconformal growth leads to excellent filling of deep features with no void space or seam along the centerline.
Plasma Electrochemistry: How to Control the Size and Size Distribution of Au Nanoparticles
Authors: Lee Seung Whan 
Published: February 2020

Metal nanoparticles (NPs) have attracted a great deal of interest for their unique optical and catalytic properties. These novel materials are normally prepared in solution as colloids by chemically reducing metal salts in the presence of a stabilizer (i.e. surfactant). Recently, we have developed a green chemical approach based on plasma electrochemical reduction (PER). A novel microplasma source that plasmas formed at sub-millimeter spatial scale allows a non-thermal, atmospheric-pressure plasma to be stably formed at the surface of aqueous ionic electrolytes and thin polymeric films. This has enabled 1) charge transfer reactions at the plasma-liquid and plasma film interface [1] and 2) electrochemical applications of plasmas for novel materials synthesis [2-6]. However, although controlling the size and size distribution of nanoparticles is a primary requirement for their application potential in diversified area, still remained question is how to control the size and size distribution in plasma electrochemical approach.
Here, we present plasma electrochemical approach to control the size and size distribution of Au nanoparticles. We initially prepared an aqueous solution including HAuCl4 and carried out PER (single-step process). In order to grow Au nanoparticles, we synthesized Au seed by PER. Afterwards, Au precursor was slowly added to grow Au seed (multi-step process). As the results, multi-step process successfully synthesized the size of Au nanoparticles at the range from ~60 nm to ~1 um
To characterize the nanoparticle films, we have employed Ultraviolet-Visible absorbance spectroscopy, Nanoparticle size and Stability Analyzer, scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

Acknowledgment

This work was supported by R&D Program of ‘Plasma Convergence & Fundamental Research’ through the National Fusion Research Institute of Korea (NFRI) funded by the Government funds.

References

[1] C. Richmonds, M. Witzke, B. Bartling, S. W. Lee, J. Wainright, C.-C. Liu, R. Mohan Sankaran, J. Am. Chem. Soc. 133, 17582 (2011).
[2] C. Richmonds and R. M. Sankaran , Appl. Phys. Lett. 93, 131501 (2008).
[3] S. W. Lee, D. Liang , X. P. A. Gao , and R. M. Sankaran Adv. Func. Mater. 21, 2155 (2011).
[4] S. W. Lee, H. Zamani, P. X. L. Feng, and R. M. Sankaran,J. Vac. Sci. Technol. A, 30, 010603, (2011).
[5] S. W. Lee, J. R. Kumpfer, P. A. Lin, G. Li, X. P. A. Gao, S. J. Rowan, R. M. Sankaran, Macromolecules 45, 8201 (2012)
[6] S. W. Lee, M. Janyasupab, C.-C. Liu, R. M. Sankaran, Catal.Today, 211 137 (2013)

Figure: Photo and particle size analysis of Au nanoparticles after single-step and multi-step plasma electrochemical reduction .

Figure 1
Co-Generation of Fuels and Chemical in Mining Processes
Authors: West Alan , Banta Scott 
Published: February 2020

We have developed an electrofuels method coupling an electrochemical reactor and a biological reactor containing chemolithoautrophic bacteria that have been engineered to produce chemicals or fuels [1,2]. Together, the two coupled reactors can use electricity generated from renewable sources to produce a chemical such as isobutyric acid or a fuel such as heptadecane from water and dilute CO2 from air. The process contains no other stoichiometric inputs, is scalable, and currently is undergoing improvements to the engineering of the bugs. While such a process is feasible, the cost of the electrical energy and the equipment motivates the exploration of alternative approaches
An alternative is discussed here, where we explore the feasibility of using chemical energy released during bioleaching processes to co-produce chemicals. Here the ore or mineral waste is the sole source of the energy required to convert CO2 and water into the chemical. The same chemolithoautrophic bacteria is exploited, since it is already used in the processing of between 10 and 25 % of the world’s copper from ore. This organism grows under acidic conditions (pH of 2) using iron and/or sulfur as it energy source. Its sole source of carbon is CO2. In theory, the organism can thus be used for co-generation of chemicals in a large variety of mining processes.
We explain the concept, present results for product formation obtained with simulated and real copper ores. Furthermore, the economic feasibility is discussed in terms of techno-economic analysis. Long term and short term possibilities for the technology are presented.
[1]. Xiaozheng Li, Roel Mercado, Sarah Berlinger, Scott Banta, and Alan C. West, ” Engineering Acidothiobacillus ferrooxidans Growth Media for Enhanced Electrochemical Processing,” AICHE Journal, accepted (September, 2014).
[2] Xiaozheng Li, Roel Mercado, Timothy Kernan, Alan C. West and Scott Banta, ”Addition of Citrate to Acidothiobacillus ferrooxidans Cultures Enables Precipitate-Free Growth at Elevated pH and Reduces Ferric Inhibition,” Biotechnology and Bioengineering, 111, 1940 (2014).
Investigation of Dy Permeation through Dy Alloy Diaphragm Using Molten Salt Electrolysis
Authors: Konishi Hirokazu , Oishi Tetsuo , Nohira Toshiyuki , Ono Hideki , Takeuchi Eiichi 
Published: February 2020

We have been developing a new process for the separation and recovery of rare earth metals using molten salt electrolysis and an alloy diaphragm. The diaphragm functions as a bipolar electrode and enables selective permeation of rare earth ions via the following steps: (1) Rare earth ions are produced by anodic dissolution of wastes containing rare earth metals in the anode room. (2) The rare earth ions are electrochemically reduced at the surface of the alloy diaphragm to form rare earth alloy. (3) The rare earth metals in the alloy diffuse to the other side surface of the alloy diaphragm and are dissolved into the cathode room as rare earth ions by anodic oxidation. (4) The rare earth ions in the cathode room are recovered as rare earth metals or alloys on a transition metal electrode. In this study, the permeation experiment was conducted with a new electrolytic cell. The current density due to alloy formation and anodic oxidation of Dy were measured individually using two potentio/galvanostats, and the results were discussed. DyCl3 was added to LiCl-KCl eutectic melts and Dy was permeated through a DyNi2 diaphragm film by potentiostatic electrolysis. The permeation rate (i.e. current density) was 280 A/m-2and the current efficiency was 98 % (max).