Energy Dispersive Spectroscopy Analysis Research Articles

Mosaic Materials in an Art Deco Steel-framed Building

ABSTRACT The mosaic coving at the Grade II* listed Freemasons’ Hall in London is an example of a mosaic on an Art Deco steel-framed building. Microstructural and chemical characterisation of loose mortars and tesserae were undertaken to inform conservation efforts and advise whether a protective coating was needed to prevent further fading of gold gilding. Rigorous testing used optical imaging, scanning electron microscopy, field emission scanning electron microscopy, energy dispersive X-ray analysis, Raman spectroscopy, X-ray diffraction, and thermogravimetric analysis with differential scanning calorimetry. Laboratory evidence demonstrated the glass tesserae were created using traditional techniques. The glass tesserae were soda-lime-silica glass with lead. The gold glass tessera was produced in the ancient Roman style which included a glass cartellina layer, so further protective coating was not needed. Historical records confirmed sheets of mosaic tesserae were prefabricated in Italy. The grout and thin-set mortar were the same low hydraulicity mortar mix, which enabled mosaic tesserae positions to be adjusted as required. The bedding coat mortar was a hydraulic cement mortar that was applied on top of an early example of foamed mortar from 1932. This unique study analyses a traditional style mosaic that was installed during a pivotal point in construction history where foamed mortars and steel framed buildings were introduced. It demonstrates how archival research and laboratory testing of small-sized samples enhance the building’s significance and architectural interest by improving the knowledge of its history.

Wear debris analysis of Al-Si/MWCNT nanocomposite during dry sliding wear tests

This study demonstrates the enhancement of wear resistance achieved by incorporating multi-walled carbon nanotubes (MWCNTs) in LM6 aluminum alloy to form nanocomposites. Experiments on wear resistance study were performed at different test parameters for various compositions of MWCNT in LM6 alloy. The size and nature of debris obtained post experiments were significantly dependent on the MWCNT contents. Wear resistance was found to increase with increase in the MWCNT fraction in the nanocomposite. The worn surface and the shape as well as the size of the debris were studied under scanning electron microscopy (SEM). Energy-dispersive spectroscopy (EDS) analysis of the worn surfaces was used to detect and measure the constituents present in the debris. SEM micrographs of the nanocomposites show that the features of the wear debris are completely altered when MWCNT was added. Further the wear mechanism underwent a change from oxidative in LM6 to that of ploughing in LM6 nanocomposite. The recorded surface roughness values also confirm the above findings and show significantly reduced surface roughness (∼82%, 0.75 wt% MWCNT). These results clearly demonstrate the advantage of addition of MWCNT for enhancing resistance to wear in LM6 alloys.

Optimization mechanism of metakaolin on micro-mechanical properties and pore characteristics of steel fiber-cement matrix interface

The study investigated the influence of aeolian sand and metakaolin (MK) on the micro-mechanical properties and pore structure characteristics of the interfacial transition zone (ITZ) between steel fibers and matrix in steel fiber-reinforced cement-based materials by nanoindentation, scanning electron microscopy (SEM) imaging, and energy-dispersive spectroscopy (EDS) analysis. The results demonstrated that including MK and aeolian sand led to a denser and uniform micro-structure in the ITZ, along with reducing the porosity and refining the pore size within there. Furthermore, MK could enhance the micromechanical properties of the C-(A)-S-H) gel by increasing the Al/Si ratio. Finally, the Copula function further confirmed the correlation between porosity (pore size >0.2 μm) and micro-mechanical properties in the ITZ. This study provides a theoretical basis for the engineering application of aeolian sand and metakaolin, and proves the feasibility of porosity to characterize the microscopic mechanical properties of the interfacial transition zone of cement-based materials. Thus, it has specific engineering value and academic significance.

Investigations of In2O3 Added SiC Semiconductive Thin Films and Manufacture of a Heterojunction Diode

This study involved direct doping of In2O3 into silicon carbide (SiC) powder, resulting in 8.0 at% In-doped SiC powder. Subsequently, heating at 500 °C was performed to form a target, followed by the utilization of electron beam (e-beam) technology to deposit the In-doped SiC thin films with the thickness of approximately 189.8 nm. The first breakthrough of this research was the successful deposition of using e-beam technology. The second breakthrough involved utilizing various tools to analyze the physical and electrical properties of In-doped SiC thin films. Hall effect measurement was used to measure the resistivity, mobility, and carrier concentration and confirm its n-type semiconductor nature. The uniform dispersion of In ions in SiC was as confirmed by electron microscopy energy-dispersive spectroscopy and secondary ion mass spectrometry analyses. The Tauc Plot method was employed to determine the Eg values of pure SiC and In-doped SiC thin films. Semiconductor parameter analyzer was used to measure the conductivity and the I-V characteristics of devices in In-doped SiC thin films. Furthermore, the third finding demonstrated that In2O3-doped SiC thin films exhibited remarkable current density. X-ray photoelectron spectroscopy and Gaussian-resolved spectra further confirmed a significant relationship between conductivity and oxygen vacancy concentration. Lastly, depositing these In-doped SiC thin films onto p-type silicon substrates etched with buffered oxide etchant resulted in the formation of heterojunction p-n junction. This junction exhibited the rectifying characteristics of a diode, with sample current values in the vicinity of 102 mA, breakdown voltage at approximately −5.23 V, and open-circuit voltage around 1.56 V. This underscores the potential of In-doped SiC thin films for various semiconductor devices.

Impact of Cobalt-Doping on the Optical, Magnetic, and Electronic Features of Hexagonal Cadmium Sulfide

CdS and Cd0.9Co0.1S samples were prepared under an N2 atmosphere. The structural analysis was conducted using X-ray diffraction. The structural and microstructure parameters were determined using Rietveld refinement method. The incorporation of cobalt ions into CdS matrix was confirmed by energy-dispersive spectroscopy and Fourier-transform infrared analysis. CdS sample has a non-magnetic feature while the Co-doped sample exhibited a magnetic behavior. The origin of magnetic property transformation has been investigated, revealing the emergence of ferromagnetic ordering and the conversion to a diluted magnetic semiconductor (DMS) with a calculated magnetic moment of 2.56 μ B upon Co doping. We also investigated how this Cobalt-doping-driven transformation affected optical, photoluminescence, and electronic properties. These effects correlated with the emergence of hyper-deep defect states. Electronic properties were calculated using density functional theory (DFT) with the HSE06 hybrid functional approximation. The calculated energy bandgaps for both Co-doped and pure CdS were 2.13 and 2.12 eV, respectively, while experimental measurements from our UV analysis yielded values of 2.26 and 2.15 eV. DFT calculations were employed to explore the magnetic properties, absorption coefficients, refractive indices, real and imaginary dielectric components, and energy loss spectra in both samples.

Effect of Zeolites on the Alkylation of Aromatics with Alkanes using a Pd Nanoparticle/Solid Acid Cooperative Catalytic System

The direct alkylation of benzene with alkanes is an effective method for alkylbenzene production. Our group previously discovered that a mixture of supported Pd nanoparticles and solid acids effectively promoted the alkylation of benzene with alkanes. Herein, the alkylation of toluene with n-heptane was catalyzed by physical mixture of H-mordenite and Pd nanoparticles supported on hydrotalcite to afford the corresponding C7 alkylation product with 87% selectivity and 14% toluene conversion. The reaction slightly proceeded in the absence of Pd nanoparticles or H-mordenite, indicating cooperative catalysis by the two different solid catalysts. Moreover, the high stability of the Pd nanoparticles on hydrotalcite was confirmed via reuse experiments and transmission electron microscopy (TEM) analysis. The catalyst mixture was reused at least three times without any loss of product yield, and after three reuses, TEM analysis revealed that the size of the Pd nanoparticles following the initial catalytic reaction was similar to that of the catalyst. Scanning transmission electron microscopy with energy dispersive spectroscopy analysis of the recovered catalyst mixture revealed the preservation of Pd nanoparticles on the hydrotalcite surface, as well as the close positioning of the two different catalyst particles, thus suggesting interparticle hydrogen transfer. The structure of the solid acid strongly affected the alkylation product selectivity. For example, H-mordenite showed high selectivity for the n-heptane alkylation product with a C7 alkyl chain, whereas the selectivity changed with other zeolites. This cooperative catalytic system can be applied to the alkylation of other substituted benzenes, such as xylenes and phenols, with good selectivity toward the desired alkylation product.

Green synthesis and characterization of binary, ternary, and quaternary Ti/MMO anodes for chlorine and oxygen evolution reactions

Dimensionally stable anodes of titanium (Ti) metal coated with mixed metal oxides (MMO) are widely used in several electrochemical applications, especially chloro-alkali electrolysis. Herein, we deposited MMO coatings on Ti substrates in different compositions, namely, (60%RuO2-40%TiO2), (60%RuO2-30%TiO2-10%IrO2), and (60%RuO2-20%TiO2-15%IrO2-5%Ta2O5), where RuO2 has the same percentage ratio in all coatings. The aim was to use these electrodes for chlorine evolution reaction (CER) and oxygen evolution reaction (OER) applications. Electrochemical characterization of the coated samples was performed to identify the best Ti/MMO electrodes with the highest efficiencies among the various prepared combinations. The role of IrO2 and Ta2O5 in enhancing corrosion resistance and electrochemical efficacy was up for debate. Scanning electron microscope (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analyses were exploited to determine the surface morphology, chemical composition, crystallinity, surface composition, and chemical states of the acquired coatings. The differential scanning calorimetry (DSC) method was used to evaluate the apparent activation energy (Ea\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\ ext{E}}}_{{\ ext{a}}}$$\\end{document}) of the deposited MMO. Additionally, the electrochemical performance of our designed coatings was scrutinized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), a current on–off test, a CV stability test (ST), and an accelerated stability test (AST). Furthermore, linear sweep voltammetry (LSV) was incorporated to assess the catalytic efficacy of the prepared anodes toward the CER in a brine solution of pH 2 and the OER in 1 M H2SO4. It became clear that the CER and OER incurred almost the same potential value (1.1 V) on both Ti/RuO2-TiO2 and Ti/RuO2-TiO2-IrO2 electrodes. However, on the Ti/RuO2-TiO2-IrO2-Ta2O5 anode, there was a 0.2 V potential difference between the CER occurring at 1.1 V and the OER happening at 1.3 V.

Experimental and molecular dynamics simulation based investigation to understand tribological performance of graphene reinforced thermoplastic polyurethane (Gr/TPU) nanocomposites

Ongoing innovative research in tribology aims to develop high-performance polymer nanocomposite (PNC) materials that offer significant improvements in efficiency, reliability, and durability across various engineering systems. Selection of appropriate nanoreinforcements is crucial for maximizing the tribological behavior in PNCs. The primary objective is to investigate how various factors, such as graphene (Gr) loadings, processing techniques, normal loading, and sliding velocity influence the tribological behavior of thermoplastic polyurethane (TPU) and graphene reinforced thermoplastic polyurethane (Gr/TPU) nanocomposites using molecular dynamics (MD) simulation and experiments. Nanocomposite materials fabricated by ultrasonication methods, test specimens are prepared in appropriate dimensions as per ASTM (American Society for Testing and Materials) and DIN (Deutsches Institut für Normung) standard. MD simulations are conducted on the developed plate and rod models under different sliding velocity, pressing and stabbing depth conditions to understand fundamental insights into the friction and wear mechanisms of Gr/TPU nanocomposites at the atomic level. Morphological studies using scanning electron microscopy (SEM) micrographs indicate no case of Gr agglomeration up to 3 wt% Gr/TPU nanocomposite. Energy dispersive spectroscopy (EDS) analysis confirms presence of Carbon (c), Nitrogen (N) and Oxygen (O) in Gr/TPU nanocomposites. Finally the obtained results from MD simulation and experiments show a significant trend of similarity.

Green Synthesis, Characterization and Antibacterial Activities of Silk Sericin Capped Zinc Oxide Nanoparticles

In recent years, interest in metal-based antibacterial materials has increased due to microorganisms gaining resistance to antibiotics. Silk sericin obtained from Bombyx mori cocoon has found use in many different areas thanks to its biocompatibility, hydrophilic character and biodegradability. Zinc oxide nanoparticles (ZnONPs) obtained in various zinc salts exhibit broad-spectrum antibacterial properties. In this study, to be produce metal based antibacterial materials, synthesis of silk sericin-coated ZnONPs (SS-ZnONPs) in a green and scalable method was investigated by using silk sericin protein as both reducing and capping agent to obtain ZnONPs. For producing SS-ZnONPs, 2% silk sericin solution was mixed with Zn(NO3)2 solution and the blend solution was heated at 100 °C for a certain period of time. Observing surface plasmon resonance (SPR) peak specific at 380 nm in the UV-vis spectrum of SS-ZnONPs represented the formation of ZnONPs. Then, the chemical, morphological, crystalline, thermal, and antibacterial properties of the synthesized SS-ZnONPs were examined. Characteristic peak of the Zn-O band was found in fourier transform infrared spectroscopy (FTIR) analysis of SS-ZnONPs. According to scanning electron microscopy (SEM) analyses, ZnONPs had morphology similar to cubic/hexagonal shape, showed a uniform structure, and did not represent any agglomerations. In energy dispersive spectroscopy (EDS) analyses of SS-ZnONPs, peaks belonging to carbon, nitrogen, oxygen, sulphur, and zinc elements were observed. The formation of Zn peak indicated that the zinc ions were transformed into ZnONPs. In addition, characteristic peaks of zinc were seen in the X-ray diffractometer (XRD) result of SS-ZnONPs. Thermogravimetric analysis (TGA) showed that the thermal stability and remaining amount of SS-ZnONPs was higher compared to pure silk sericin powder due to the formation of ZnONPs. Lastly, agar well diffusion test was carried out with Staphylococcus aureus (ATCC 6538) and Escherichia coli (ATCC 25922) bacteria and SS-ZnONPs showed antibacterial action against S. aureus. It has been observed that the obtained SS-ZnONPs can be used as antibacterial agents. However, it was also understood that the ZnONPs concentration in this study was low for high antibacterial activity.

Anti-adhesion study of three-dimensional reconstructed carbon coatings

This research study focuses on the investigation of a three-dimensional reconstructed carbon coating based on stainless steel. The investigation encompasses the assessment of surface structure, elemental composition, cytotoxicity, and impact on wound healing. The findings indicate that the carbon coating possesses an approximate thickness of 700 nm, exhibiting a distinctive porous structure. Moreover, the surface water contact angle measures 97.7°, representing a 48.4° increase compared to uncoated stainless steel. Energy-dispersive spectroscopy (EDS) analysis confirms the uniform distribution of diverse elements on the coating’s surface. Additionally, X-ray photoelectron spectroscopy (XPS) verifies a substantial carbon accumulation. The electrical resistance of the stainless steel remains largely intact after the application of the coating, as demonstrated by the four-probe method. Notably, ex vivo porcine liver tissue cutting experiments using carbon-coated electrosurgical pencil electrodes showed a significant anti-adhesion effect, with a reduction in tissue adhesions of 81.3%. Furthermore, the MTT test indicates no significant cytotoxicity associated with the carbon coating. Rat skin-cutting experiments further validate that the coating does not impede the process of wound healing. Overall, this study successfully validated the desirable properties of stainless steel-based 3D reconstructed carbon coatings, such as enhanced surface properties, improved anti-adhesion efficacy, negligible cytotoxicity, and compatibility with wound healing. These findings are important for advancing medical device technology and improving patient outcomes.

Parameter development and characterization of laser powder directed energy deposition of Nb – Alloy C103 for thin wall geometries

This work focuses on the parameter development and microstructural characterization of Nb-based alloy C103 for thin wall structures produced via laser powder – directed energy deposition (LP – DED). Laser power and scanning speeds were varied as part of a design of experiments to identify adequate print parameters. Combinations were evaluated for relative density, porosity, and geometrical accuracy. A combination of a laser power of 1420 W and scanning speed of 14 mm/s resulted in a relative density >99%, exhibited a consistent weld bead profile and was used for further microstructural evaluation. A mix of optical and scanning electron microscopy (SEM) revealed small, slightly elongated grains along the edges and large epitaxial grains in the central region along the Build – Transverse view. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis revealed Hf rich columnar cells in the center that transition into an evenly spaced cellular structure towards the edges of the built sample. Electron backscatter diffraction (EBSD) scans show a sharp [001] texture when looking at the cross section of the sample along the build direction. The Build – Scan view revealed a zig – zag pattern that follows the back – and – forth deposition strategy that was used. Finally, microhardness measurements were taken in the as – built (AB) and stress relieved (SR) conditions to baseline preliminary mechanical properties. The AB condition exhibited a large amount of scatter in the data and averages up to 11% larger than the SR condition. The reduction in scatter upon applying the SR cycle are indicative of a large concertation of dislocations present in the AB condition.

Investigation of the physico-chemical properties of In2S3 powder synthesized via solid-state reaction and In2S3 thin films prepared through thermal evaporation

In this study, we examined the physico-chemical properties of In2S3 powder produced using the solid-state reaction and of the In2S3 thin film obtained using the thermal evaporation technique. Thermally evaporated In2S3 thin films were subjected to vacuum annealing to study the impact of heating on the structural, morphological and optical properties of the samples. According to the X-ray diffraction analysis, the microstructure of as-grown thin films were an amorphous in nature which transformed into polycrystalline structure after annealing at T≥250 °C. This polycrystalline structure suggests the formation of the β-In2S3 phase with a tetragonal and/or cubic crystal structure. In addition, the energy dispersive spectroscopy analysis revealed that all samples show a slight excess of indium and a deficit of sulfur, compared to the stoichiometric ratios. Moreover, surface micrographs recorded by atomic force microscopy showed an increase in surface roughness after annealing. Optically, the transmittance spectra, T(λ), illustrated a high transmittance average value,∼70 %, while the reflectance spectra, R(λ), showed an average value of 25 % in the visible and NIR region. It appeared that heat treatment had no significant impact on the T and R spectra. The optical dispersion parameters of the treated samples were also studied. The direct and indirect allowed bandgap transitions values of all samples were found to ranging from 1.75 to 2.48 eV and from 1.80 to 2.38 eV, respectively. Such observation shows that the bandgap increased with annealing temperature. Electrically, n-type conductivity for In2S3 films annealed at 250 °C was recorded.

Microstructural effects and constitutive modelling of cyclic softening behaviour in Ti–6Al–4V titanium alloys

Cyclic softening in Ti–6Al–4V titanium alloy significantly influences the reliability and performance of critical engineering components. This study addresses the lack of a comprehensive understanding of cyclic softening in different microstructures of Ti–6Al–4V titanium alloys. Microstructures with bimodal and lamellar morphologies were prepared by heat treatment of Ti–6Al–4V titanium alloy at various temperatures. Interrupted low-cycle fatigue tests revealed a larger cyclic softening for the bimodal microstructures than the lamellar microstructures. Finite element analysis (FEA) captured the cyclic softening by incorporating the Voce isotropic hardening model with the Chaboche kinematic hardening model. Two nonlinear kinematic hardening terms, along with the Voce isotropic hardening model whose parameters were calculated using the variation in cyclic yield strength and cyclic stress amplitude resulted in good prediction for bimodal and lamellar microstructures, respectively. The accuracy of the model is further improved when a linear kinematic term is added to it. Transmission electron microscope, electron backscatter diffraction, and energy dispersive spectroscopy analysis revealed that the extensive softening in the bimodal microstructure is associated with the dislocation localization in the primary alpha (αp) leading to a considerable plastic strain accumulation and subsequent crystal re-orientation. The alloying element partitioning, lamella width, and the ease of slip transmission at the secondary alpha (αs) and beta (β) interface also play essential roles in the cyclic softening.

Moderate magnitude clockwise rotation of the Yunlong Basin: Implications for synchronous Eocene rotation of the southeastern Tibetan Plateau

The clockwise rotation and southeastward extrusion of the southeastern Tibetan Plateau have played important roles in accommodating the uplift and deformation of the plateau. Numerous paleomagnetic studies have suggested post−late Eocene clockwise rotation of the southeastern Tibetan Plateau along the eastern Himalaya syntaxis, whereas few researchers have addressed the specific Eocene deformation, leading to ambiguous interpretations of the tectonic evolution in the region. Herein, we conducted a paleomagnetic study of the Yunlong Formation in the Yunlong Basin, which is Late Cretaceous to early Paleocene in age. In total, 386 oriented samples were collected. Rock magnetic, scanning electron microscopy (SEM), and energy-dispersive spectroscopy (EDS) analyses revealed detrital carriers, such as hematite and some magnetite. In thermal demagnetization processes, 332 characteristic remanent magnetizations were isolated, which yielded positive reversals and tilt tests, providing a site-mean direction of declination (Ds) = 56.0° ± 2.6°, inclination (Is) = 34.3° ± 3.8°, α95 = 2.7°, k = 91.0, and N = 31 after tilt correction. Magnetostratigraphic analysis was performed, and a depositional age of 79−61 Ma for the section was obtained, which is consistent with the previous paleontological and detrital zircon ages. Compared with the Eurasia reference pole of the period, the data revealed a 45.2° ± 5.1° clockwise rotation of the Yunlong area since 79−61 Ma. The integrated regional paleomagnetic results suggest the occurrence of ∼20° of clockwise rotation of the Lanping-Simao terrane during the Eocene, which is similar (in terms of magnitude and time of occurrence) to that of the Gonjo Basin in the eastern Qiangtang terrane. Integrated with other lines of geologic evidence, we propose a new deformation model in which the entire southeastern Tibetan Plateau experienced ∼20° of rigid clockwise rotation during the Eocene, followed by subsequent oroclinal bending.

Effects of pyrite, quartz and sodium sulfite on roasting of a refractory sulfide concentrate and gold, silver, copper leaching during cyanidation

The oxidation roasting pretreatment process, which is a mature and dominant industrial practice for treating complex polymetallic gold deposits, has a low recovery of associated silver and exhibits an unclear reaction sequence. This study takes a silver-containing gold ore as the research object and investigates the effect of (i) sodium sulfite as an additive, (ii) main gold-bearing mineral pyrite, and (iii) gangue mineral quartz, on silver during the roasting process in roasting and leaching tests. Characterization techniques included scanning electron microscopy–energy dispersive spectroscopy analysis, and thermogravimetry–differential scanning calorimetry analysis. The results based on thermodynamic calculations and characterization show that the main reason for the low extraction of silver is that the calcined product (i.e., iron silicate) formed by the reaction between pyrite and quartz during the roasting process is mutually absorbed and wrapped with silver oxide. In addition, silver minerals decompose some iron sulfides and iron oxides under high-temperature conditions, promoting the reaction of iron and quartz to form iron silicate while strengthening the secondary encapsulation of silver by products of roasting, thus deteriorating the extraction of silver. The addition of sodium sulfite reduces the formation of iron silicate and increases the extraction of silver by directly promoting the conversion of pyrite to iron oxide. This study provides a theoretical basis for further improving the roasting and leaching of silver.

Effect of annealing temperature on carbide precipitation, microstructure and mechanical properties of Fe-Mn-C- (Cr, Mo, W, Ni, Nb, Ti, V) multi-alloying TWIP steel

The effect of annealing temperature on the microstructure, carbide precipitation and mechanical properties of a cold-rolled multi-alloying TWIP steel were investigated by means of Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) analysis, tensile and impact tests. As the temperature increases from 400 °C to 800 °C, the amount of carbides climbed to the peak at 700 °C and then decreased, having a strong opposite relationship with the impact energy, which was minimum 26 J at 700 °C. The main distribution of carbides underwent a transition from intragranular, intragranular + intergranular to intergranular, and the composition of carbides changed from (Nb, Ti and W) to (Cr, Mo and W). Compared with the cold-rolled sample, Fe21W2C6 precipitated out at low annealing temperature of 400 °C, when the tensile and yield strengths and elongation were all simultaneously improved due to the precipitation recovery annealing. And the 600 °C annealing sample exhibited identical yield and tensile strengths. Subsequently, the yield strengths decreased but the tensile strengths and elongation increased at 650 °C and 700 °C attributed to the interaction of carbide precipitation and recrystallization. The recrystallization started at 650 °C and finished at 750 °C. And Fe3Mo3C was identified at 750 °C.

Microstructure and Magnetic Properties of Fe67.6-Pd32-In0.4 (at.%) Shape Memory Melt-Spun Ribbons.

Fe-~30 at.%Pd is a ferromagnetic shape memory alloy (SMA) with a reversible thermoelastic fcc-fct phase transformation. The advantage of adding a small amount of Indium to Fe-Pd SMAs is, among other things, the upward shift of the transformation temperatures, which allows us to maintain the material in the martensitic state (fct structure) at room temperature. In this work, we study the microstructure and the magnetic properties of nominally Fe67.6-Pd32-In0.4 (at.%) melt-spun ribbons. Energy-dispersive spectroscopy analysis showed a certain level of non-uniformity of Indium distribution in the as-spun ribbon. However, the attempt to homogenize the ribbon by annealing at 1273 K for 120 h resulted in an unfavoured structural change to bct martensite. Magneto strains induced by a 9 kOe magnetic field reached over 400 ppm for certain field orientations, which is around four times more than the magneto strains of near-binary Fe-Pd shape memory alloys.

Effect of Sulfide Addition on the Corrosion Mechanism of Copper in Saline Groundwater Solution

The interaction of copper with sulfide-containing simulated saline groundwater is studied by electrochemical techniques (voltammetry, current-time transients, and electrochemical impedance spectroscopy, EIS) complemented with surface and cross-sectional microscopic observations and energy dispersive spectroscopic analyses. Both experimental findings and quantitative interpretation of EIS data using previously published kinetic models indicate that no continuous adherent barrier-type layer is formed on Cu in sulfide-containing groundwater, thus precluding the possibility of the development of localized corrosion modes.

Utilizing municipal solid waste incineration bottom ash and volcanic tuff to produce geopolymer materials

Large volumes of municipal solid waste incineration bottom ash (MSWIBA) are produced annually in China; however, their improper disposal causes serious ecological and environmental problems. This study investigated the feasibility of using MSWIBA and volcanic tuff to produce geopolymers. The effects of the MSWIBA content, silicon–sodium molar ratio, and alkali equivalent on the uniaxial compressive strength (UCS) and bulk density of the geopolymer samples were examined using single-factor and optimization tests. The test results showed that the UCS and bulk density of the geopolymer decreased as the MSWIBA content increased, whereas they increased as the alkali equivalent increased. As the silicon–sodium molar ratio increased, the UCS first increased and then decreased, and the change in bulk density was limited. In the final geopolymer preparation, the MSWIBA content was 17.85%, the silicon–sodium molar ratio was 1.71, and the alkali equivalent was 9.49%. According to X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, energy-dispersive spectrometry, and nuclear magnetic resonance analyses, the main phases of the geopolymer under the final preparation parameters were quartz, sanidine, calcite, orthoclase, gismondine, and illite. During the geological polymerization process, a large amount of CNASH gel was generated and attached to the surface of the particles or filled the pores between the particles, resulting in a pore size of 0.01–1 μm. The heavy metals in the geopolymers exhibited a good stabilization effect owing to the CNASH gel. Except for Cd, which posed a medium risk, the remaining heavy metals posed low or no risk.

Dynamic mechanical damping analysis of up/step-quenched Cu-Zn-Sn-based shape memory alloys

The effect of thermal quenching procedures on the damping properties of Cu-Zn-Sn-based SMAs is reported. Three compositions of Cu-Zn-Sn-based SMAs designated A (Cu-15.6Zn-12.1Sn), B (Cu-26.1Zn-9.3Sn), and C (Cu-29.6Zn-8.9Sn) samples produced by the casting process were subjected to direct quenching, up-quenching, and step-quenching treatments. The microstructure of the samples was examined using the backscattered electron microscope with fixtures for energy-dispersive spectroscopy analysis. The damping properties were assessed on a dynamic mechanical analyzer and presented in terms of tan delta. The microstructures of Cu-Zn-Sn-based SMAs consist of γ-Cu5Zn8 and Cu4 major phases containing some black dot precipitation and a small amount of white circular precipitates in the parent phase. For the A alloys, the step-quenched samples exhibited the highest damping capacity with peak internal friction of 0.041 at 37 °C, which is greater than 0.028 at 37 °C and 0.26 at 25 °C obtained for the up-quenched and direct-quenched samples respectively. The step-quenched B alloys show the highest damping capacity with peak internal friction of 0.104 at 227 °C, which is far greater than 0.053 at 23 °C and 0.034 at 35 °C obtained for the up-quenched and direct-quenched samples respectively. For the C alloys, the up-quenched samples show the highest damping capacity with peak internal friction of 0.053 at 235 °C, which is greater than the peak values of 0.037 at 23 8 °C obtained for the step-quenched samples. Direct-quenched samples gave the lowest damping capacity with a peak value of 0.027 at 235 °C. In general, step-quenching treatment effectively improved the damping properties of Cu-Zn-Sn-based SMAs.