Presence Of Other Phases Research Articles

Toward improving the performance of Cu2ZnSnS4-based solar cells with Zr, W or sulfurized layers at the SnO2:F/Cu2ZnSnS4 rear interface

The photovoltaic performance of Cu2ZnSnS4 (CZTS)-based thin film solar cells with transparent back contacts is mainly constrained by the ohmic loss due to degradation of the back contacts at high temperatures required for the growth of the CZTS absorbers. This work has attempted to use ultrathin Zr and W interlayers at the SnO2:F (FTO)/CZTS interface with the purpose of improving the ohmic properties of FTO and hence the performance of solar cells. 20 nm thick Zr and W layers were coated on FTO using direct current magnetron sputtering, followed by heating at 550 °C in a sulfur atmosphere for some of the samples. Inclusion of Zr and W interlayers compromised the transmittance of the FTO back contact, however heating of the samples in a sulfur atmosphere improved the transmittance to values comparable to or better than those of un-heated FTO. Furthermore, heated W/FTO showed a significant improvement in electrical conductivity as observed from Hall effect measurements. To make complete solar cells, CZTS absorber, buffer (CdS) and window (i-ZnO/ZnO:Al) layers were sequentially deposited on the un-heated FTO, Zr/FTO, W/FTO and Mo back contacts. Glow discharge optical emmision spectroscopy confirmed that Zr and W did not diffuse into the absorber and also prevented Na diffusion into the absorber. From the scanning electron microscopy cross sectional analysis, an impovement in the absober grain size and a clear junction between the absorber and FTO with W interlayer were observed. Grazing incident X-ray diffractometry confirmed the polycrystalline nature of the CZTS thin films and indicated the presence of other phases, particularly SnS2. On the resulting solar cell parameters, the inclusion of a W interlayer reduced the series resistance from 4.5 Ωcm to 3.7 Ωcm2. An improvement in short circuit current density (JSC) is also observed, enhancing the efficiency of the solar cells with CZTS/W/FTO to 3.1 % compared to that with CZTS/Mo at 2.7 % and CZTS/FTO at 3.0 %. W was found to improve the external quantum efficiency response and JSC of the solar cells for both backside and frontside light illumination. On the other hand, inclusion of a Zr interlayer (Zr/FTO) only slighlty improved the open circuit voltage, but compromised the JSC compared to FTO and W/FTO back contacts. Thus, the findings of this study demonstrate the prospect for improving the performance of the CZTS-based thin film solar cells through the inclusion of ultrathin Zr and W interlayers between the FTO back contact and CZTS absorber.

Effect of rapid solidification in Mn2FeSi alloy formation and its physical properties

The structure and magnetic properties of Mn2FeSi alloy as a prospective Heusler material are studied from the viewpoint of the rapid solidification technology used for its preparation. The planar flow casting leads due to fast cooling of the melted material to formation of ribbons with different structural and physical properties. In present study, the crystalline ribbon-type samples are produced and subjected to detail analysis using electron microscopy, positron annihilation spectroscopy, X-ray diffraction, as well as magnetic and Mössbauer measurements. It is shown that the as-prepared Mn2FeSi ribbon is paramagnetic at room temperature and adopts a cubic structure with lattice parameter of 0.567 nm and Néel temperature of antiferromagnetic/paramagnetic transition around 45 K. The presence of other phase(s) observed at low temperatures is reflected also in changes of the structural and physical properties after sample annealing at 773 K for 100 h. The results of microstructure, magnetic, and phase composition observations are completed by the positron life time measurements suggesting single vacancies as the main defects in which the positrons are trapped.

Molecular Dynamics Simulation Prediction of the Partitioning Constants (KH, Kiw, Kia) of 82 Legacy and Emerging Organic Contaminants at the Water-Air Interface.

The tendency of organic contaminants (OCs) to partition between different phases is a key set of properties that underlie their human and ecological health impacts and the success of remediation efforts. A significant challenge associated with these efforts is the need for accurate partitioning data for an ever-expanding list of OCs and breakdown products. All-atom molecular dynamics (MD) simulations have the potential to help generate these data, but existing studies have applied these techniques only to a limited variety of OCs. Here, we use established MD simulation approaches to examine the partitioning of 82 OCs, including many compounds of critical concern, at the water-air interface. Our predictions of the Henry's law constant (KH) and interfacial adsorption coefficients (Kiw, Kia) correlate strongly with experimental results, indicating that MD simulations can be used to predict KH, Kiw, and Kia values with mean absolute deviations of 1.1, 0.3, and 0.3 logarithmic units after correcting for systematic bias, respectively. A library of MD simulation input files for the examined OCs is provided to facilitate future investigations of the partitioning of these compounds in the presence of other phases.

Horizontal Stratified Air–Foam–Water Flows: Preliminary Modelling Attempts with OLGA

Water accumulation is a major problem in the flow assurance of gas pipelines. To limit liquid loading issues, deliquification by means of surfactant injection is a promising alternative to the consolidated mechanical methods. However, the macroscopic behavior of foam pipe flow in the presence of other phases has barely been explored. The goal of this work was to propose an approach to simulate air–water–foam flows in horizontal pipes using OLGA by Schlumberger, an industry standard tool for the transient simulation of multiphase flow. The simulation results were compared with experimental data for 60 mm and 30 mm ID (Inner Diameter) horizontal pipelines. Preliminary validation for two-phase air–water flow was carried out, which showed that correct flow pattern recognition is essential to accurately reproduce the experimental data. Then, stratified air–foam–water flows were investigated, assuming different models for the foam local velocity distribution. Foam rheology was considered through the Herschel–Bulkley model with the yield stress varying in time due to foam decay. The results showed good agreement for a uniform velocity profile and fresh foam properties in the case of the 60 mm ID pipeline, whereas for the 30 mm ID, which was characterized by significantly higher velocities, a linear velocity profile and 2000 s foam aging provided the best agreement. In both cases, the pressure gradient was overestimated, and the mean absolute prediction error ranged from about 5% to 30%.

Temperature dependence of Raman and photoluminescence spectra of pure and high-quality MoO3 synthesized by hot wall horizontal thermal evaporation

In this work, a novel system for the hot wall evaporation of MoO3 in a horizontal furnace and at low vacuum atmosphere was settled. Pure MoO3 material was obtained without the presence of other phases and with a strong preferential orientation, as revealed by electron microscopy, micro-Raman spectroscopy and x-ray diffraction. Photoluminescence and Raman spectra were measured as a function of temperature. As a result, the first-order temperature coefficient of the fifteen measured vibrational modes is reported and compared with the scarce literature data available. The relation of these coefficients with the thermal expansion coefficient is discussed in the framework of the Grüneisen model. Moreover, for the first time, the temperature dependence of the different contributions of photoluminescence spectra for MoO3 is reported, and an anomalous increase in PL intensity of all transitions is observed in the range of 40–140 K, followed by a normal quenching at high temperatures. The Shibata model was used to interpret the origin of this anomalous effect.

Effect of Microwave-Assisted Synthesis and Sintering of Lead-Free KNL-NTS Ceramics.

Lead-free piezoelectric powders (K0.44Na0.52Li0.04)(Nb0.82Ta0.10Sb0.04)O3 were obtained by conventional and microwave-assisted reactive heating. Firstly, the synthesis of the material was carried out following the mixed oxide route and employing both traditional methods and microwave technology. Thermogravimetry, X-ray diffraction, field emission scanning electron microscopy and electrical properties analyses were evaluated. X-ray diffraction of the powders calcined by the microwave process shows the formation of perovskite structure with orthorhombic geometry, but it is possible to observe the presence of other phases. The presence of the secondary phases found can have a great influence on the heating rate during the synthesis on which the kinetics of the reaction of formation of the piezoelectric compound depend. The calcined powder was sintered at different temperatures by conventional and non-conventional processes. The microstructure of the ceramics sintered by microwave at 1050 °C for 10 min shows perovskite cubes with regular geometry, of size close to 2–5 µm. However, the observed porosity (~8%), the presence of liquid phase and secondary phases in the microstructure of the microwave sintered materials lead to a decrease of the piezoelectric constant. The highest d33 value of 146 pC/N was obtained for samples obtained by conventional at 1100 °C 2 h compared to samples sintered by microwave at 1050 °C 10 min (~15 pC/N).

Combination of iodine-deficient BiOI phases in the presence of CNT to enhance photocatalytic activity towards phenol decomposition under visible light

In this work, we have prepared BiOI/CNT composites by hydrothermal method and studied the impact of CNT and hydrothermal treatment conditions (temperature and time) simultaneously on phenomena such as crystallization. The samples were studied using X-ray Diffraction (XRD), nitrogen sorption (Brunauer–Emmett–Teller (BET) specific surface areas), Scanning Electron Microscopy assisted with Energy Dispersive X-Ray spectroscopy (SEM-EDX), High Resolution Transmission Electron Microscopy (HRTEM), UV–vis Diffuse Reflectance spectroscopy (DRS), Raman spectroscopy and photoluminescence spectroscopy (PL). The different heat treatments applied and varied amount of CNT was found to have a profound effect on the structural, morphological, compositional and optical properties of the prepared composites. The distinguishable changes in the above-mentioned properties were clearly visible for the samples prepared at higher temperature and longer duration (150 °C, 6.30 h). Surprisingly, the presence of other phases of BiOI, such as Bi7O9I3, Bi4O5I2, Bi5O7I, also co-existed at the same time, although in low amount. Finally, for the study, the photocatalytic efficiency of the prepared samples was tested for phenol and RhB, as model pollutants, under visible light irradiation for 240 min and 120 min, respectively. The results revealed that the composites prepared at higher temperature with longer duration showed superior performance for the photodegradation of phenol and RhB. Additionally, the composites performed better than their respective reference samples in each case. Interestingly, the introduction of CNT promoted the crystallinity in the composites and promising results for the removal of phenol and RhB were achieved by the use of low power ordinary visible lamps.

ANALYSES OF WASTE PRODUCTS OBTAINED BY LASER CUTTING OF AW-3103 ALUMINIUM ALLOY

In the presented research, the methods of scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction and transmission electron microscopy were applied to analyse the powder waste obtained by cutting of AW-3103 aluminium alloy using a fibre laser. The scanning electron microscopy allows to analyse the morphology of the waste microparticles, the energy-dispersive X-ray spectroscopy revealed their chemical composition, which was compared with the composition of the original cut material. In the waste powder, mainly plate-like particles were observed that contain almost pure aluminium. X-ray powder diffraction measurements confirmed that the waste powder is composed of aluminium phase with only a slight presence of other phases (magnetite, austenite and graphite) and the transmission electron microscopy revealed the presence of nanoscale particles in this waste powder. Furthermore, it was found that the average size of the microparticles depends on the thickness of the cut material: particles obtained from a thicker workpiece were substantially bigger than those obtained from the thinner material. On the contrary, the dimensions of the workpiece have only a little impact on the particles’ shape and no significant influence on their chemical composition. The results also suggest that the microparticles could be used as an input material for powder metallurgy. But there is also a certain health risk connected with inhalation of such tiny particles, especially the nanoparticles, which can penetrate deep into the human pulmonary system.

Cyclic Oxidation of Titanium Grade 2.

This paper presents the results of research into the cyclic oxidation of titanium Grade 2. The value of titanium Grade 2 oxidation activation energy was determined based on an analysis of the Arrhenius diagram. The result was 205.3 kJ/mol. After cyclic oxidation at a temperature of 600 °C, the presence of oxides in an acicular system was observed on the surface. The specimen surface after oxidation at 650 °C was characterised by the presence of fine oxide particles, while after oxidation at 700 °C, the obtained oxide layer was composed of large oxide particles. The layers obtained after oxidation at 600 °C had the lowest thickness (1.26 and 2.12 µm), while those obtained at 700 °C had the highest thickness (5.17 and 9.45 µm). Examination of the phase composition after cyclic oxidation showed that the oxide layers obtained at temperatures of 600, 650 and 700 °C were composed of TiO2 (rutile) only. No presence of other phases was found. The oxide layers formed in the cyclic oxidation process were characterised by different thicknesses, depending on the oxidation parameters. It was found that cyclic oxidation contributed to a considerable increase in the surface hardness of titanium Grade 2.

Correlations of grain boundary segregation to sintering techniques in a three-phase ceramic

The effects of using different sintering techniques (conventional, flash and spark plasma sintering) on grain boundary segregation were investigated in a 3-phase polycrystalline ceramic containing cubic 8 mol% Y2O3 stabilized ZrO2 (YSZ), α-Al2O3 and MgAl2O4. Six types of interfaces for each sintered sample were analyzed for grain boundary chemistry. Using aberration-corrected STEM and EDS, we show Al segregation at YSZ-YSZ boundaries, and Y/Zr segregation at Al2O3-Al2O3, MgAl2O4-MgAl2O4 and MgAl2O4-Al2O3 boundaries. YSZ-MgAl2O4 and YSZ-Al2O3 heterointerfaces, in contrast, do not show elemental segregation. Our results show that the type of segregation at different boundaries does not change with different sintering processes, indicating that elemental segregation mainly depends on initial sample composition, although the amount of segregation can vary. Quantitative analyses reveal that spark plasma sintering (950°C for 5 min, 100 MPa) results in relatively higher average segregation at grain boundaries and heterointerfaces compared to conventional sintering (1550°C for 10 h), suggesting that low temperatures result in higher grain boundary segregation. The average segregation concentrations at the grain boundaries of our flash sintered sample (estimated to reach 1700°C for 6 s) were found to be consistently similar to long-annealed spark-plasma sintered sample (1350°C for 20 h), suggesting that very high temperatures reached during flash process can achieve similar segregation concentrations compared to a SPS sample annealed for several hours at lower temperature. The presence of other phases in multi-phase systems can modify the grain boundary chemistry and segregation compared to segregation in single-phase ceramics.

Thermal, mechanical, and electrical properties of LSCo/mullite composite contact materials for solid oxide fuel cells

AbstractLanthanum strontium cobaltite (LSCo) is considered as a good candidate cathode contact material for solid oxide fuel cells, due to high electrical conductivity. However, LSCo has a very large coefficient of thermal expansion (CTE) than the cells and metallic interconnects. As a result, poor mechanical stability is expected during thermal cycling. To minimize the CTE mismatch, we investigate a composite approach involving mixing LSCo with an inert material of low CTE, such as mullite at volume fractions from 0.1 to 0.4. Composite's CTE shows a decreasing trend with increasing mullite volume fractions and is consistent with model predictions. X‐ray powder diffraction analysis of sintered LSCo/mullite composites exhibits no presence of other phases for samples aged for 500 hours at 800°C, indicating chemical compatibility. Electrical conductivity by a 4‐pt method shows a decreasing trend with increasing mullite content. Contact strength of as‐sintered and thermally cycled samples show that only the composite with 0.4 volume fraction has a measurable strength; the other composites have no strength. Overall, the composite approach is demonstrated in the LSCo/mullite system to lower the CTE and hence achieve thermal cycle stability. The addition of the inert phase to the LSCo matrix, however, also reduces the electrical conductivity.

Heavily Doped Zinc Oxide Thin Films for Nitrogen Dioxide Optical Gas Sensing

Introduction In this work heavily n-doped ZnO doped with gallium, germanium, aluminum and silicon are studied for NO2 detection, using the sensibility of localized surface plasmonic resonance in the near infrared to the change of environmental conditions. Trivalent cations (Al3+ and Ga3+) or tetravalent cations (Si4+ and Ge4+) are used as dopant agents with nominal concentration of 20%, following a non-aqueous heat up colloidal synthesis [1]. No presence of other phases like metal, dopant oxides, and binary dopant-ZnO oxides is detected by XRD analysis. It is proved by spectrophotometric analysis that introduction of doping agent causes the formation of a surface plasmon resonance in the near infrared, tunable changing dopant nature. We have demonstrated that strong sensitivity of the plasmon resonance to chemical variations at the surface of the nanocrystal make this category of materials very suitable for detection of 1000 ppm NO2 balance in air, finding the best compromise between sensitivity, signal to noise ratio and stability of the sensor in 20% germanium doped ZnO. Materials and Methods Synthesis: Doped ZnO NPs were synthetized through a previously reported non-aqueous heat up colloidal method [2]. Film preparation: Doped zinc oxide thin films were prepared by spin coating technique on fused silica substrates. The films were thermal treated in a tube furnace filled with a 5% H2−95% Ar gas mixture at 450°C for 2h [3]. The final thickness of the films were of 500-600 nm. Film characterization: Nanoparticles morphology and dimension were observed by transmission electron microscope (TEM). Morphology of the films and an estimation of doping efficiency were investigated using a scanning electron microscope (SEM). Crystalline structure of thin films was determined by grazing incidence X-ray diffraction (XRD). Gas sensing measurement were performed in a Harrick gas flow cell connected to a gas handling system via flow meters and coupled with a Jasco V-570 spectrophotometer. Optical absorption was collected using the Jasco V-570 spectrophotometer in the 350-2500 nm wavelength range at operative temperature (OT) set at 150°C in 0.4 L/min flow of synthetic air or of target gas. In this work, 1000 ppm of NO2 in dry air was used as target gas. Optical Absorption Change (OAC = Absgas - Absair) was evaluated to identify the suitable wavelength to perform the dynamic sensing. Results and Conclusions In general, at equilibrium in dry air condition, atmospheric molecular oxygen is adsorbed onto sensor’s surface, due to the interaction with oxygen vacancies, and ionizing. In this work sensing test are performed at 150°C, at this temperature O2¯ is considered stable. If nitrogen dioxide is introduced, equilibrium changes due to the gas’ high oxidizing attitude, which increase the concentration of adsorbed molecules and cause an increment of electrons’ extraction. Therefore, the thickness of Electron Depletion Layer as well as the resistance of material increase. Due to this phenomenon, sensor response can be defined in several different ways as function of differences in measurement criteria. In particular, changing in resistance is most commonly monitoring parameter used for chemoresistive gas sensors, but besides the obvious electrical effects, it can be observed from formula (1) that decreasing in carrier density the angular frequency of LSPR maximum peak’s position decrease and, as consequence, its wavelength increase, obtaining a red-shift of the plasmon position.In Figure 1 are presented the OAC of the various thin films tested and two cycles of Air/NO2 exposition. We found that all the prepared samples are able to detect 1000 ppm of NO2 in dry air but with different dynamic characteristic. In particular, a trade-off between sensibility and signal to noise ratio versus stability was highlighted, which depend from the amount of free charge generated by the dopant agent. In fact, GZO thin film exhibit higher sensitivity and signal to noise ratio, but lower recovering of the baseline due to progressive irreversible degradation of the sensor. On the contrary, SZO has approximately total recovering of baseline but the signal difference between air and gas exposition is lower. GeZO exhibit intermediate proprieties with both good sensitivity and baseline recovering, while AZO present the worst sensing behaviors. The use of colloidal approach to the synthesis overcome some limitations of the sol-gel method, making this process competitive by an industrial point of view compared to other common investigated deposition technique, like magnetron sputtering. In the same time allow to obtain nanoparticles easily dispersible and depositable at room temperature and in ambient condition.Future works will investigate cross-sensitivity and detection limit of so obtained NO2 sensors. Analyzed sensing proprieties coupled with optical transparence in visible light, paving the way to the fabrication of new invisible and highly efficient sensors for detection of hazardous gases.

An investigation on the phase purity of iron pyrite (FeS2) thin films obtained from the sulfurization of hematite (Fe2O3) thin films

Iron pyrite (FeS2) thin films were obtained by sulfurization of hematite (Fe2O3) thin films at different sulfurization temperatures (TS) and sulfurization time (tS). Phase purity of sulfurized films was investigated with X-ray diffraction, Raman Spectroscopy and Vibrating sample magnetometry (VSM). Sulfurization temperature and time were found to have a complementary effect on the phase purity of pyrite films. Secondary phase formation in the pyrite films decreased with increasing sulfurization temperature or time. Pyrite films confirmed to be phase pure with XRD and Raman spectroscopy showed the presence of other phase(s) when analyzed with VSM. Merely XRD measurements were not sufficient to claim the phase purity of pyrite films.

Synthesis, characterization and in vitro antimicrobial prospecting of silver-doped ceria

In this work, Ag-doped CeO2 samples containing 0.5 mol% Ag+ were successfully synthesized by the polymeric precursor method and then calcined at 400, 500, 600 and 700 °C for 2 h. X-ray diffraction and Raman spectra indicated that the crystals have a fluorite-type structure without the presence of other phases. The size of the Ce0.95Ag0.05O1.9−δ crystals increased from 6.61 to 27.46 nm upon increasing the thermal treatment temperature. The decomposition of the samples was examined by differential thermal analysis to determine the most suitable calcination temperature to apply to the materials and indicate the steps involved in obtaining Ag-doped ceria. Scanning electron microscopy images revealed small crystallite sizes, the presence of oxygen vacancies, structural stability and homogeneity. The Ag-doped ceria have shown effective and efficient antimicrobial activity, inhibiting the growth of Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa bacteria. However, pure CeO2 displayed no antibacterial activity. Therefore, the satisfactory antimicrobial activity reported here can be attributed to the partial substitution of cerium ions by silver ions.

Friction Welding of Titanium to Stainless Steel Using Al Interlayer

Dissimilar friction welding between titanium and 304 austenitic stainless steel with aluminum as insert layer was examined to amend the joint properties and interface characteristics. To insert the interlayer into the joint, a two-step method was used. The resultant of the joint interfaces was characterized to reveal the reactions between interlayer and parent metals using scanning electron microscope, X-ray diffraction and electron probe micro-analyzer. Microhardness and tensile tests were used to evaluate the mechanical properties of the joints. It was observed that the development of brittle phases of FeTi and CrTi in the welded joint was successfully precluded using aluminum interlayer, whereas the presence of other phases which were in ductile nature compared to the FeTi- and CrTi-type phases of AlTi and FeAl was identified. The absence of reaction compounds and brittle phases ensued improvement in the mechanical and microstructural properties of the aluminum insert layer joints.

Characterization of α-Fe-Free Heteroepitaxial NdFe12−x Ti x Thin-Film Materials with a Novel Cubic Laves Fe2Ti Phase

Thin films with compositions of NdFe12 and NdFe11Ti1 were fabricated on W-buffered MgO(001) substrates of varying roughness. In this study, X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the films microstructurally, chemically, and crystallographically. This study revealed successful heteroepitaxial synthesis of the tetragonal NdFe12 and NdFe12−x Ti x phases in the Ti-free and Ti-containing films, respectively, both with surface-normal c-axis orientation. It also revealed the presence of other phases within the magnetic layer. The NdFe12 films contained many α-Fe particles, which preferentially precipitated at locally rough regions of the W-buffer interface. The NdFe11Ti1 film showed the ubiquitous presence of an Fe2Ti phase, which covered most of the buffer thereby preventing the formation of α-Fe. This phase was determined to have a novel Cu2Mg-type cubic Laves (C15) crystal structure with fourfold interfacial symmetry, good coherency, and a low mismatch with the W-buffer, thus rendering itself as being an ideal interface for the heteroepitaxial synthesis of NdFe12−x Ti x crystals. It is proposed that successful application of a cubic Fe2Ti underlayer on W can contribute to the development of a fabrication strategy for NdFe12 thin films without the presence of soft magnetic α-Fe.

Optical and Multiferroic Properties of Gd‐Co Substituted Barium Hexaferrite

AbstractThis report demonstrates Gd‐Co substituted M‐type barium hexaferrite, Ba1‐xGdxCoxFe12‐xO19, successful synthesis adopting sol gel method. Formation of crystalline magneto‐plumbite structure and presence of other phases are verified from the X‐ray diffraction analysis. Vibrational modes in FT‐Raman spectra show the formation of P63/mmc group can be related with magneto‐plumbite structure. TEM images of these materials are also discussed. UV‐Vis‐NIR spectra shows that with material substitution optical energy band gap increases 3.99 eV to 4.28 eV. The observed Fe3+ ions peak could be correlated to peak line width and occurrence of symmetrical resonance in electron spin resonance (ESR) spectra. The dielectric constant shows high value at low frequency and it becomes constant at high frequency. The retentivity and coercivity of the material decreases with increasing substitution. Multiferroic nature of hexaferrite is analyzed using ferroelectric loops.

Structural Analysis of the Selected Products From the Suspension Furnace Produced in the Internal Recycling

AbstractThere are presents the internal recycling in anode furnace, in addition to mainly blister copper and converter copper. During the process there arise the two types of semi-finished products intended for further pyro metallurgical processing: anode copper and anode slag. The stream of liquid blister copper enters into the anode furnace treatment, in which the losses are recovered, e.g. copper, resulting from oxidation and reduction of sulfides, oxides and the oxidation of metallic compounds of lead, zinc and iron. In the liquid phase there are still gaseous states, which gives the inverse relationship relating to the solid phase, wherein the gases found an outlet in waste gas or steam. The results of chemical analysis apparently differ from each other, because crystallite placement, the matrix structure and the presence of other phases and earth elements are not compared, which can be regained in the process of electrorefining. One should not interpret negatively smaller proportion of copper in the alloy, since during the later part of the production more elements can be obtained, for example from sludge, such as platinum group metals and lanthanides. According to the research the quality of blister copper, to a large extent, present in the alloy phase to many other elements, which can be recovered.

Hybrid Perovskite, CH3NH3PbI3, for Solar Applications: An Experimental and Theoretical Analysis of Substitution in A and B Sites

The effect of the incorporation ofNH4+into the CH3NH3+sites of the tetragonal perovskite CH3NH3PbI3is analysed. Also, how it affects the introduction of Cd2+cations into Pb2+sites for a perovskite with 25 at.% ofNH4+is addressed. The incorporation ofNH4+into perovskite leads to a dramatic loss of crystallinity and to the presence of other phases. Moreover, the NH4PbI3was not found. The less formation of perovskite whenNH4+is incorporated is due to geometrical factors and not changes in the chemical state bonding of the ions. Also, the samples where perovskite is formed show similar band gap values. A slight increase is observed for samples withx=0.5and 0.75. For the sample withx=1, a drastic increase of the band gap is obtained. Periodic-DFT calculations agree with the experimental structural tendency whenNH4+is incorporated and the density of states analysis confirmed the experimental band gap. The perovskite with 25 at.% ofNH4+was selected for studying the effect of the concentration of Cd on the structural and electronic properties. The theoretical band gap values decreased with the Cd concentration where the narrowing of Cd s-states in the conduction band plays an important role.

The Occurrence of Breithauptite and Nisbite-Like Sb-Ni Phases At Sindesar-Khurd, Rajasthan, India: Implications For Melt-Assisted Sulfide Remobilization

Abstract Breithauptite (NiSb) generally occurs in magmatic Ni-Cu-PGE ores and in hydrothermal veins associated with Ni and Co arsenide minerals. Its presence in the Rajpura-Dariba–Sindesar-Khurd–Bethumni metallogenic belt, Rajasthan, India, may be ascribed to metamorphic remobilization as observed elsewhere, e.g ., Sulitjelma, Norway. From the coexistence of breithauptite with probable Sb-Ni melt phases at Sindesar-Khurd, a temperature of approximately 930–970 °C is indicated from the phase relations in the Ni-Sb binary phase diagram. However, this temperature is substantially above the peak metamorphic temperature of 580–600 °C estimated from equilibrium silicate phase assemblages in the rocks around the Rajpura-Dariba ore body, which is situated six kilometers to the south of Sindesar-Khurd. We have conducted experiments at 600 °C in the Ni–Sb system in the presence of Ag to understand if Ag is responsible for such a drastic decrease of the temperature of melting. The presence of other phases including freibergite [(Ag,Cu,Fe,Zn) 12 Sb 4 S 13 ], Ag-rich tetrahedrite [(Cu,Ag,Fe,Zn) 12 Sb 4 S 13 ], ∼2FeS.Ag 2 S, and ∼CuPbSbS 3 .Ag 2 S along with breithauptite at Sindesar-Khurd indicates the selective incorporation of Ag. In a second assemblage nisbite (NiSb 2 ) instead of breithauptite was observed along with 3PbS.Ag 2 S, 2Ag 2 S.FeS, (Fe,Ag)S, a Sb-Ni-Ag-Fe-S phase, and a Ag-Sb-Ni-Cu-Fe-S phase. Nisbite is stable only below 628 °C, suggesting that these assemblages formed below this temperature, and the presence of several additional phases of variable compositions further indicates disequilibrium and probable rapid crystallization from a melt. Our results suggest that Ag significantly depresses melting temperatures in the Ni–Sb system, making possible the existence of an Ag-Sb-Ni melt at 600 °C. In the presence of S and other elements such as Fe, Pb, Cu, etc . the melting temperature would be further depressed. Thus the removal of Ag from the melt through formation of Ag-bearing phases, e.g ., 2FeS.Ag 2 S, 3PbS.Ag 2 S, 2Ag 2 S.FeS, or CuPbSbS 3 .Ag 2 S, may result in a residual metastable melt at the ambient temperature. Such a melt may quench to a fine-grained assemblage containing breithauptite and nisbite-like Sb-Ni solid phases, such as encountered at Sindesar-Khurd. The second assemblage, which is nisbite-bearing, could result from a relatively Ag-rich Ni-poor melt fraction that becomes extremely Sb-rich due to the removal of Ag.