bluuebunny/crossref_metadata_2025_split huggingface dataset:
Salt weathering of limestones: susceptibility of petrographical features (SEM study)
Authors: Alves C. , Figueiredo C. , Maurício A. , Aires-Barros L. 
Published: August 2013

Salt weathering is one of the main processes affecting rock materials applied in the built environment. Scanning electron microscopy (SEM) studies can contribute to the understanding of the susceptibility of petrographic features of rocks to salt weathering.SEM studies were performed in limestones (grainstones with the commercial designations of Semi-rijo and Moca Creme and a travertine) submitted to salt weathering tests (EN 12370 using sodium sulphate solutions and cubic specimens) consisting of 15 cycles of immersion/drying followed by water washing after the 15th cycle. Fragments from small cubes of the grainstones subjected to salt weathering cycles without the final water cleaning were also studied. SEM observation before and after the tests allows the discussion of the petrographical characteristics of these rocks that contribute to erosive decay under salt weathering.In the case of the grainstones specimens the texture can be described in general as allochemical particles cemented by sparry calcite (Figure 1 a) and it is visible from the preparation of the polished surfaces the interface between the sparry cement and the allochemical components. After the salt weathering tests, SEM studies show (Figure 1 b) extensive fissuring in the sparry cement and separation between grains and sparry cement. Observations of disaggregation products showed an important amount of apparently intact grains. These results are similar to those observed by with the sparry cement being affect by salt crystallisation and lesser impact on the grains. Studies in the unwashed specimens showed the presence of sodium sulphate in the interface between allochemical grains and the sparry cement (Figure 1 c,d). Travertine specimens show heterogeneous patterns of erosion attributed to the heterogeneous texture of this rock, with more terrigenous (especially clay-rich) portions that favour a higher erosive susceptibility and the presence of clays has been frequently connected with salt weathering susceptibility in limestones. In Figure 1e can be observed the heterogeneity of a polished surface, with the more irregular portions showing a chemical spectra (Figure 1 f) indicative of the terrigenous component and the presence of sodium and sulphate (resulting from the solutions used in these weathering tests).The authors acknowledge the support of the Fundação para a Ciência e Tecnologia (POCTI/CTA/44940/2002; PEst-OE/CTE/UI0697/2011 and Pest-OE/CTE/UI0098/2011, funding by the European Union and national budget of the Portuguese Republic). Acknowledgments to Eng. Teresa Luís, Eng. Sónia Pereira and Enterprise Mármores Galrão for the rock blocks.
Applications of Nuclear Techniques, Computer Simulation and Microscopy to Surface Analysis of Materials
Authors: Pacheco de Carvalho J. , Pacheco C.F.R. , Reis A.D. 
Published: August 2013

There is a wide range of surface analysis techniques which are, generally, complementary. Nuclear and non-nuclear techniques have been available. Nuclear techniques, which are non-destructive, provide for analysis over a few microns close to the surface of the sample, giving absolute values of concentrations of isotopes and elements. They have been applied in areas such as scientific, technologic, industry, arts and medicine, using MeV ion beams. Nuclear reactions permit tracing of isotopes with high sensitivities. We use ion-ion nuclear reactions, elastic scattering and the energy analysis method where, at a chosen energy of the incident ion beam, an energy spectrum is recorded of ions from nuclear events, coming from several depths in the target. Such spectra are computationally predicted, giving target composition and concentration profile information. A computer program has been developed in this context, mainly for flat targets. The non-flat target situation arises as an extension. Successful applications of the method are given using the 18O(p,α0)15N reaction and elastic scattering of (4He)+ ions. SEM and TEM are used as useful complementary techniques.Two types of samples were prepared containing thick and thin oxides, respectively. The first sample (S1) was obtained by high temperature oxidation of austenitic steel in C 18O2 gas. Weight gain measurements had given a 4.2 μm thick oxide. SEM has shown a reasonably flat oxide (Figure 1 (a)). The second sample (S2, also labelled Al/Al2O3) was obtained by anodization of high purity aluminium at 100V in an aqueous solution of ammonium citrate. An oxide thickness of 0.1370 μm was expected. TEM has given an oxide film thickness of 0.1340 μm (Figure 1 (b)). The 18O(p,α0)15N reaction at Ep=1.78 MeV and 165º was used to analyse sample S1. Figure 2 (a) shows a good computed fit to data. A 18O step concentration profile was found, corresponding to a thick 18O oxide with thickness X1=4.4 μm. Sample S2 was analysed by elastic scattering of α particles at Eα=2.0 MeV and 165º. Figure 2 (b) shows a good computed fit to data. A thin oxide film thickness of X1=0.1350 μm was found, close to the TEM value. The fit also shows a ratio of atomic densities of O and Al slightly above 1.5. The combined use of nuclear techniques, SEM and TEM microscopy has proved to be very important for surface analysis of materials. The reported results would be difficult to obtain by other techniques.Supports from University of Beira Interior and FCT (Fundação para a Ciência e a Tecnologia)/PEst-OE/FIS/UI0524/2011 (Projecto Estratégico-UI524-2011-2012) are acknowledged.
SEM characterization of gelatin-ionic liquid functional polymers
Authors: Carvalho R.N.L. , Matias S.C. , Lourenço N.M.T. , Fonseca L.P. 
Published: August 2013

ION JELLY® patented technology is based on the cross-linking of Ionic Liquids (ILs) with Gelatin that results in a viscous gel that can be molded into a film or a block, and solidifies by cooling below 35 ºC . The outcome of this combination is a transparent, light and flexible conductive polymer that adapts perfectly to a great variety of surfaces. Some of the key properties of ION JELLY® are: high stability up to 180ºC, large electrochemical window and bio-compatibility. Taking in consideration the attractive attributes of ILs, that provide a stable and friendly environment for the enzymes, where they retain their catalytic activity, combined with the morphologic advantage of gelatin, we have decided to study this new protein-ionic-based material regarding water content, swelling behaviour, and structural morphology by scanning electron microscopy (SEM).The properties of [emim][EtSO4] and [bmim][N(CN)2] ION JELLY® films were compared with those of solely gelatin. Thin films were prepared with different amounts of water or phosphate buffer and left to maturate in a controlled atmosphere for 4 days. Swelling was carried out in water at 4ºC and films were lyophilized afterwards. SEM images of ION JELLY® and gelatin films were obtained prior and after these steps.ION JELLY® films were rubbery while gelatin films were glassy. Water-made ION JELLY® had completely smooth surfaces, just like gelatin, but buffer-made ION JELLY® exhibited salt crystals on the surface, as well as some superficial pores (Figure 1). Free water content in [emim][EtSO4] ION JELLY® was found to be greater than [bmim][N(CN)2] ION JELLY® and gelatin.The swelling ratio of both types of ION JELLY® was close to 100%, while gelatin swelled 8 times more. The swollen lyophilized gelatin films formed a heterogeneous and highly porous network (Figure 2), while ION JELLY® films were more homogeneous with a lower degree of porosity (Figure 3).These results showed that ION JELLY® is a polymer with a more tightly bound structure than gelatin. This material allows water to penetrate, but possesses a higher rigidity that prevents too much mobility of the polymeric chains. Considering that it’s a biocompatible polymer, lyophilized swollen ION JELLY® could have potential applications as a scaffold for biological material.Financial support received from the Portuguese Science and Technology foundation (Fundação para a Ciência e Tecnologia) under the grants SFRH/BD/77568/2011, PTDC/EBB-BIO/114288/2009, PTDC/EBB-BI/099237/2008 and SFRH/BPD/41175/2007 and Projecto Estratégico IBB: PEst – OE/EQB/LA0023/2011
Quantitative Analysis of Carbon in Silicon Carbide Coated with Carbon
Authors: Lee Hongrim , Kim Junsu , Yun Jondo 
Published: August 2013

AbstractNonconductive specimens for scanning electron microscopy or X-ray microanalysis are coated with conductive carbon in order to reduce charging. But carbon film absorbs X-ray fluxes causing errors in measuring chemical composition. Especially when the carbon content is measured, carbon coating not only blocks X-rays but also becomes a source of carbon X-rays. It is thus necessary to determine how much errors are induced by carbon coating, and how thick coating is allowed for the accurate measurement. In this study, quantitative analysis of carbon on silicon carbide with carbon coating films was attempted by electron probe microanalyzer. It was found that measured carbon content increased in a nonlinear manner up to 40% with a film thickness, whereas silicon content decreased slightly. Carbon X-ray intensity was determined by computer simulation, which increased in a linear manner with the thickness. The discrepancy was due to a nucleation and growth of islands and thus a change of density with a thickening of coating film.
Microstructure Characterization of ZK60 Magnesium Alloys Using TEM and HR-EBSD
Authors: Cho Jae-Hyung , Kim Soo-Hyun , Han Sang-Ho , Kang Suk-Bong 
Published: August 2013

AbstractZK60 (Mg–Zn–Zr) alloys exhibited a variation in precipitates with aging, and their mechanical properties also changed. Microindentation tests were carried out on two types of ZK60 alloys of solid solution (T4) and peak aging (T6). Microstructure and texture evolution during indentation was investigated using electron backscatter diffraction. Twinning occurred near the indentation marks in most grains. It was found that tensile twinning was dominant, and two twin variants were usually observed. Texture and microstructure evolution by twinning and slip activation was further examined by uniaxial compression test with strain. The initial random orientation gradually changed into basal fibers with strain. Some grains with nonbasal orientations aligned with the loading direction easily underwent twinning followed by slip deformation. Other grains near basal orientations revealed only slip deformation.
Phase Analysis on Dual-Phase Steel Using Band Slope of Electron Backscatter Diffraction Pattern
Authors: Kang Jun-Yun , Park Seong-Jun , Moon Man-Been 
Published: August 2013

AbstractA quantitative and automated phase analysis of dual-phase (DP) steel using electron backscatter diffraction (EBSD) was attempted. A ferrite–martensite DP microstructure was produced by intercritical annealing and quenching. An EBSD map of the microstructure was obtained and post-processed for phase discrimination. Band slope (BS), which was a measure of pattern quality, exhibited much stronger phase contrast than another conventional one, band contrast. Owing to high sensitivity to lattice defect and little orientation dependence, BS provided handiness in finding a threshold for phase discrimination. Its grain average gave a superior result on the discrimination and volume fraction measurement of the constituent phases in the DP steel.
Statistical Analysis on Static Recrystallization Texture Evolution in Cold-Rolled AZ31 Magnesium Alloy Sheet
Authors: Park Jun-Ho , Ahn Tae-Hong , Choi Hyun-Sik , Chung Jung-Man , Kim Dong-Ik , Oh Kyu Hwan , Han Heung Nam 
Published: August 2013

AbstractCast AZ31B-H24 magnesium alloy, comprising Mg with 3.27 wt% Al and 0.96 wt% Zn, was cold rolled and subsequently annealed. Global texture evolutions in the specimens were observed by X-ray diffractometry after the thermomechanical processing. Image-based microstructure and texture for the deformed, recrystallized, and grown grains were observed by electron backscattered diffractometry. Recrystallized grains could be distinguished from deformed ones by analyzing grain orientation spread. Split basal texture of ca. ±10–15° in the rolling direction was observed in the cold-rolled sample. Recrystallized grains had widely spread basal poles at nucleation stage; strong {0001} basal texture developed with grain growth during annealing.
Amorphization Induced by Focused Ion Beam Milling in Metallic and Electronic Materials
Authors: Huh Yoon , Hong Ki Jung , Shin Kwang Soo 
Published: August 2013

AbstractFocused ion beam (FIB) milling using high-energy gallium ions is widely used in the preparation of specimens for transmission electron microscopy (TEM). However, the energetic ion beam induces amorphization on the edge of specimens during milling, resulting in a mischievous influence on the clearness of high-quality transmission electron micrographs. In this work, the amorphization induced by the FIB milling was investigated by TEM for three kinds of materials, metallic materials in bulk shape, and semiconductive and electronic ceramic materials as a substrate for the deposition of thin films.
In Situ Transmission Electron Microscopy Imaging of Electromigration in Platinum Nanowires
Authors: Rudneva Maria , Gao Bo , Prins Ferry , Xu Qiang , van der Zant Herre S.J. , Zandbergen Henny W. 
Published: August 2013

AbstractIn situ transmission electron microscopy was performed on the electromigration in platinum (Pt) nanowires (14 nm thick, 200 nm wide, and 300 nm long) with and without feedback control. Using the feedback control mode, symmetric electrodes are obtained and the gap usually forms at the center of the Pt nanowire. Without feedback control, asymmetric electrodes are formed, and the gap can occur at any position along the wire. The three-dimensional gap geometries of the electrodes in the Pt nanowire were determined using high-angle annular dark-field scanning transmission electron microscopy; the thickness of the nanowire is reduced from 14 nm to only a few atoms at the edge with a gap of about 5–10 nm.
In Situ Heating Transmission Electron Microscopy Observation of Nanoeutectic Lamellar Structure in Sn–Ag–Cu Alloy on Au Under-Bump Metallization
Authors: Seo Jong-Hyun , Yoon Sang-Won , Kim Kyou-Hyun , Chang Hye-Jung , Lee Kon-Bae , Seong Tae-Yeon , Fleury Eric , Ahn Jae-Pyoung 
Published: August 2013

AbstractWe investigated the microstructural evolution of Sn96.4Ag2.8Cu0.8 solder through in situ heating transmission electron microscopy observations. As-soldered bump consisted of seven layers, containing the nanoeutectic lamella structure of AuSn and Au5Sn phases, and the polygonal grains of AuSn2 and AuSn4, on Au-plated Cu bond pads. Here, we found that there are two nanoeutectic lamellar layers with lamella spacing of 40 and 250 nm. By in situ heating above 140°C, the nanoeutectic lamella of AuSn and Au5Sn was decomposed with structural degradation by sphering and coarsening processes of the lamellar interface. At the third layer neighboring to the lamella layer, on the other hand, Au5Sn particles with a zig-zag shape in AuSn matrix became spherical and were finally dissipated in order to minimize the interface energy between two phases. In the other layers except both lamella layers, polycrystal grains of AuSn2 and AuSn4 grew by normal grain growth during in situ heating. The high interface energy of nanoeutectic lamella and polygonal nanograins, which are formed by rapid solidification, acted as a principal driving force on the microstructural change during the in situ heating.
Electron Holography Study of the Charging Effect in Microfibrils of Sciatic Nerve Tissues
Authors: Kim Ki Hyun , Akase Zentaro , Shindo Daisuke , Ohno Nobuhiko , Fujii Yasuhisa , Terada Nobuo , Ohno Shinichi 
Published: August 2013

AbstractThe charging effects of microfibrils of sciatic nerve tissues due to electron irradiation are investigated using electron holography. The phenomenon that the charging effects are enhanced with an increase of electron intensity is visualized through direct observations of the electric potential distribution around the specimen. The electric potential at the surface of the specimen could be quantitatively evaluated by simulation, which takes into account the reference wave modulation due to the long-range electric field.
The Effects of Maintaining Temperature in Annealing Heat Treatment for an FSWed 6061-T6 Al Alloy
Authors: Lee Seung-Jun , Han Min-Su , Kim Seong-Jong 
Published: August 2013

AbstractThe technological development of all kinds of lightweight transportation devices including vehicles, aircraft, ships, etc. has progressed markedly with the demand for energy saving and environmental protection. Aluminum alloy is in the spotlight as it is a suitable environmentally friendly material. However, deformation is a major problem during the welding process because aluminum alloy has a large thermal expansion coefficient. In addition, it is known that its corrosion resistance is excellent; nevertheless, in practice, considerable corrosion is generated and this is a major problem. To solve this problem, the friction stir welding (FSW) technology is applied extensively at various industrial fields as a new welding technique. This method involves a process in which materials are joined by frictional heat and physical force. Therefore, we evaluated improvements in mechanical properties and corrosion resistance through annealing heat treatment after FSW. The electrochemical experiment did not show a significant difference. However, the microstructure observation showed defectless, fine crystal particles, indicating excellent properties at 200–225°C.
An Investigation on the Optimum Corrosion Protection Potential for Minimization of Cavitation Damage Using the Potentiostatic Method in Seawater
Authors: Kim Seong-Jong , Jang Seok-Ki , Park Jae-Cheul 
Published: August 2013

AbstractIn this study, we replaced the expensive blade material with an aluminum–bronze alloy that has excellent corrosion resistance and cavitation characteristics and developed the corrosion protection method to improve durability using an electrochemical method. The objective of this study was to identify the electrochemical corrosion protection conditions to minimize cavitation damage due to generating hydrogen gas (2H2O + 2e− → 2OH− + H2) by means of hydrogen overvoltage before the impact pressure of the cavity is transferred to the surface. In the constant potential experiment under the cavitation environment, the energy was reflected or cancelled out by collision of the cavities with the hydrogen gas generated by the hydrogen overvoltage. As a result, the optimal corrosion prevention potential in the dynamic state is assumed to be the range of −1.4 to −1.7 V, which is the range at which active polarization took place.
Scale-Bridging Analysis on Deformation Behavior of High-Nitrogen Austenitic Steels
Authors: Lee Tae-Ho , Ha Heon-Young , Hwang Byoungchul , Kim Sung-Joon , Shin Eunjoo , Lee Jong Wook 
Published: August 2013

AbstractScale-bridging analysis on deformation behavior of high-nitrogen austenitic Fe–18Cr–10Mn–(0.39 and 0.69)N steels was performed by neutron diffraction, electron backscattered diffraction (EBSD), and transmission electron microscopy (TEM). Two important modes of deformation were identified depending on the nitrogen content: deformation twinning in the 0.69 N alloy and strain-induced martensitic transformation in the 0.39 N alloy. The phase fraction and deformation faulting probabilities were evaluated based on analyses of peak shift and asymmetry of neutron diffraction profiles. Semi in situ EBSD measurement was performed to investigate the orientation dependence of deformation microstructure and it showed that the variants of ε martensite as well as twin showed strong orientation dependence with respect to tensile axis. TEM observation showed that deformation twin with a {111}⟨112⟩ crystallographic component was predominant in the 0.69 N alloy whereas two types of strain-induced martensites (ε and α′ martensites) were observed in the 0.39 N alloy. It can be concluded that scale-bridging analysis using neutron diffraction, EBSD, and TEM can yield a comprehensive understanding of the deformation mechanism of nitrogen-alloyed austenitic steels.
Microstructural Study on Kirkendall Void Formation in Sn-Containing/Cu Solder Joints During Solid-State Aging
Authors: Liu Zhi-Quan , Shang Pan-Ju , Tan Feifei , Li Douxing 
Published: August 2013

AbstractKirkendall void formation at the solder/metallization interface is an important reliability concern for Cu conductors and under-bump metallization in microelectronic packaging industry, whose mechanism is still hard to be understood for different individual cases. In the present work, two typical solder/Cu-diffusing couples, eutectic SnIn/Cu and SnBi/Cu, were studied by scanning/transmission electron microscopy to investigate the microstructural evolution and voiding process after soldering and then solid-state aging. It was concluded that Kirkendall voids formed between two sublayers within Cu2(In,Sn) phase in eutectic SnIn/Cu solder joint, whereas they appeared at the Cu3Sn/Cu interface or within Cu3Sn for eutectic SnBi/Cu solder joint. Besides the effect of impurity elements, the morphological difference within one intermetallic compound layer could change the diffusing rates of reactive species, hence resulting in void formation in the reaction zone.
Identification of Local Phase of Nanoscale BaTiO3 Powders by High-Resolution Electron Energy Loss Spectroscopy
Authors: Moon Sun-Min , Wang Xiaohui , Cho Nam-Hee 
Published: August 2013

AbstractThe electron energy loss spectroscopy (EELS) technique was applied to investigate the local variation in the phase of barium titanate (BaTiO3) ceramics. It was found that the fine structure of the titanium L2,3 edge and their satellite peaks were sensitively varied with the tetragonal–cubic phase transition. The peak splitting of Ti-L3 edge of tetragonal-phased BaTiO3 ceramics was widened because of the increased crystal field effect compared with that of cubic-phased BaTiO3. In case of nanoscale BaTiO3 powders, the L3 edge splitting of the core region was found to be smaller than that of the shell region. The energy gap between peaks t2g and eg varied from 2.36 to 1.94 eV with changing the probe position from 1 to 20 nm from the surface. These results suggest that the EELS technique can be used to identify the local phase of sintered BaTiO3 ceramics.
Interfacial Structure and Electrical Properties of Transparent Conducting ZnO Thin Films on Polymer Substrates
Authors: Lim Young Soo , Kim Dae Wook , Kang Jong-Ho , Seo Seul Gi , Kim Bo Bae , Choi Hyoung-Seuk , Seo Won-Seon , Cho Yong Soo , Park Hyung-Ho 
Published: August 2013

AbstractThe effects of polymer substrates on the interfacial structure and the thermal stability of Ga-doped ZnO (GZO) thin films were investigated. The GZO thin films were deposited on polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) substrates by rf-magnetron sputtering at room temperature, and thermal stability tests of the GZO thin films on the polymer substrates were performed at 150°C up to 8 h in air. Electrical and structural characterizations of the GZO thin films on the PET and the PEN substrates were carried out, and the origins of the stable interfacial structure and the improved thermal stability of the GZO thin film on the PEN substrate were discussed.