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All available thermodynamic data and phase diagram data in the Al2O3–ZrO2, CaO–Al2O3–ZrO2, and Al2O3–SiO2–ZrO2 systems at 1 bar total pressure were critically evaluated and assessed simultaneously to obtain a set of the optimized Gibbs energies of all phases in the systems. Due to the lack of reliable data on the mutual solubility of Al2O3 and ZrO2, key phase diagram experiments in the Al2O3–ZrO2 binary system were carried out by using a classical phase equilibrium and quenching technique followed by the EPMA phase analysis. Based on the optimized Gibbs energies, the reliable experimental phase diagram and thermodynamic property data of the Al2O3–ZrO2, CaO–Al2O3–ZrO2, and Al2O3–SiO2–ZrO2 systems are well reproduced, and unknown phase diagram and thermodynamic properties are predicted.

The mineralising effect of CuO on microstructure and phase composition of SO3 -doped clinker was studied by a combination of phase analysis, light and scanning electron microscopy and QXRD. Results show proportionally higher C4 AF content in clinker interstitial matter due to CuO doping. CuO also lowers the SO3 incorporation in main clinker phases C3 S and C2 S. Observation in back-scattered electrons revealed that Cu crystallises mainly as a Cu-rich phase in the clinker interstitial matter and inclusions in crystals of C2 S with distorted structure. CuO partially inhibits the incorporation of Fe2 O3 in C2 S.

This paper aims at the phase identification and quantification in transformation induced plasticity duplex stainless steel (TDSS) base and weld metal containing ferrite, austenite, and martensite. Light optical microscopy (LOM) and electron backscatter diffraction (EBSD) analysis were employed to analyze phases. Samples were either mechanically or electrolytically polished to study the effect of the preparation technique. Mechanical polishing produced up to 26% strain-induced martensite. Electrolytic polishing with 150 g citric acid, 300 g distilled water, 600 mL H3PO4, and 450 mL H2SO4 resulted in martensite free surfaces, providing high-quality samples for EBSD analysis. Martensite identification was challenging both with LOM, due to the similar etching response of ferrite and martensite, and with EBSD, due to the similar lattice structures of ferrite and martensite. An optimized Beraha color etching procedure was developed that etched martensite distinctively. A novel step-by-step EBSD methodology was also introduced considering grain size and orientation, which successfully identified and quantified martensite as well as ferrite and austenite in the studied TDSS. Although here applied to a TDSS, the presented EBSD methodology is general and can, in combination with knowledge of the metallurgy of the specific material and with suitable adaption, be applied to a multitude of multiphase materials. It is also general in the sense that it can be used for base material and weld metals as well as additive manufactured materials. This study received support from the EU-project H2020-MSCA-RISE-2018 Number 823786, i-Weld, and the Swedish Agency for Economic and Regional Growth through the European Union–European Development Fund

Lisään tiedoston kun VoR on saatavilla (LH) Funding Information: This work was partly financed by the Aalto University School of Chemical Engineering. The Academy of Finland’s RawMatTERS Finland Infrastructure (RAMI) based at Aalto University, GTK Espoo, and VTT Espoo was utilized in this study. The authors are grateful to the China Scholarship Council for financial support [Grant Number 201806370217, 201706370096]. This study received financial support from the Project funded by China Postdoctoral Science Foundation [Grant Number 2020TQ0059, 2020M680967] and the Natural Science Foundation of Liaoning Province. Mr. Junmo Jeon is greatly appreciated for his assistance in XRD analyses. The authors declare that they have no conflict of interest. Publisher Copyright: © 2021, The Author(s). We investigated the phase relations of the SiO2-MgO-TiO2 system in air at 1500°C using the high-temperature isothermal equilibration/quenching technique, followed by x-ray diffraction measurements and direct phase analysis using scanning electron microscopy coupled with x-ray energy dispersive spectrometry. One single liquid phase domain, five two-phase domains (liquid-TiO2, liquid-cristobalite, liquid-MgO·SiO2, liquid-2MgO·SiO2, and liquid-MgO·2TiO2), and five three-phase regions (liquid-TiO2-MgO·2TiO2, liquid-MgO·SiO2-cristobalite, liquid-TiO2-cristobalite, liquid-MgO·SiO2-2MgO·SiO2 and liquid-2MgO·SiO2-MgO·2TiO2) were observed. We constructed a 1500°C isothermal phase diagram based on the experimentally measured liquid compositions. We compared simulations using MTDATA and FactSage thermodynamic software and their databases with the experimental results obtained in this study. These results can be used to provide guidelines for updating the MTDATA and FactSage titania-bearing thermodynamic databases by reassessing the thermodynamic properties of the phase with new experimental data.

To meet the requirements of automatic production, a new type of green BAl88Si cored solder was developed. The lap brazing experiments were carried out with copper and aluminum as brazing substrates. The microstructure, phase composition, and corrosion behavior of solder joint interface were studied by field emission scanning electron microscopy, energy dispersive spectroscopy, transmission electron microscopy, electron backscattering diffraction, tensile testing machine, and electrochemical workstation. The results show that the brazing joint of Cu/BAl88Si/Al is metallurgical bonding, and the brazing joint of Cu/BAl88Si/Al is composed of Cu9Al4, CuAl2, a-Al, (CuAl2 + a-Al + Si) ternary eutectic. In addition, there is no obvious preference for each grain in the brazing joint, and there are S texture {123}, Copper texture {112}, and Brass texture {110}. The interface of Cu9Al4/CuAl2 is a non-coherent crystal plane and does not have good lattice matching. The average particle size of CuAl2 is 11.95 µm and that of Al is 28.3 µm. However, the kernel average misorientation (KAM) value at the brazed joint interface is obviously higher than that at the brazed joint interface copper, so the defect density at the brazed joint interface aluminum is higher than that at the brazed joint interface copper. At the same time, due to poor corrosion resistance at the interface on the aluminum side of the brazed joint, serious corrosion spots and corrosion cracks occur at the same time, which leads to the shear performance of the brazed joint decreasing by about 75% after salt spray test for 240 h.

A new refractory alloy, CrHfNbZrTa0.5, was prepared by a vacuum arc-melting, and its phase analysis, microstructures, and compressive properties in as-cast and annealed conditions were investigated. The phase components of the as-cast CrHfNbZrTa0.5 alloy were mainly composed of BCC + Laves phases, while an extra HCP phase emerged after annealing. The yield strength of the as-cast and annealed alloys were 1457 and 1517 MPa respectively, both which are significantly larger than 929 MPa of the most concerned HfNbTaTiZr. The relatively stable high-strength of the as-cast and annealed alloys might originate from the high ductility-brittle temperature and the intrinsic strength of the Cr-containing Laves phase.

For the first time, yttrium-iron-garnet films with a thickness of 0.5 µm on nonoriented single-crystal lithium niobate LiNbO3 substrates are obtained by the ion-beam sputtering–deposition method. The surface profile and composition of the samples obtained are studied by atomic force microscopy, scanning electron microscopy, and X-ray phase analysis. Based on the data of optical and magnetic measurements, as well as the results of studies of spin-wave propagation in ferrite-garnet films on LiNbO3 substrates, we conclude that the reproducible formation of high-quality structures by nonepitaxial methods is possible for obtaining optically transparent straintronic materials, as well as the development of microwave electronic materials.

Nanocrystalline ceramic samples of the ZrO2–3 mol % Y2O3 composition with varying degrees of tetragonality c/a (1.4337 and 1.0425) are obtained. The process of the low-temperature degradation of ceramics is studied by the methods of X-ray phase analysis and electron microscopy. It is found that samples with a high degree of tetragonality are more resistant to the action of a humid environment, while the phase composition in the bulk of the samples remains practically unchanged and the transformation t-ZrO2 → m-ZrO2 occurs mainly in the surface layers without significantly affecting the mechanical properties of the ceramics.

The present study investigated the effect of mechanical alloying (MA) time, preheating and annealing process on phase and microstructural transformations in Al65Cu23Fe12 (at%) alloys. To release stresses, a part of milled powder was heated at 150 °C for 20 min and then raw compacts of the as-synthesized powders and preheated ones were prepared and heated at selected temperatures from 200 to 800 °C using microwave radiation. The results showed that with increasing the time of mechanical alloying process, the morphology of the particles changed and nanometer spherical particles were formed. Also, β-Al(Cu,Fe) solid solution phase was formed after 16 h of mechanical alloying. After 30 h of mechanical alloying, the quasi-crystalline phase did not form directly under the conditions employed in this work. Comparison of preheated samples with samples without preheating process showed that the quasi-crystal phase was formed at 300 °C for preheated samples, while the β phase was formed for samples without preheating process. The results of phase analysis also showed that β-Al(Cu,Fe) and θ-Al2Cu phases along with the quasi-crystalline phase are the main phases in the samples. The annealing process of the samples using microwave radiation leads to the formation of a quasi-crystal phase at temperatures and times much lower than other annealing methods.

We successfully refined a cheap commercial boron powder by means of high-energy ultra-sonication and utilized it in synthesis of bulk MgB2. Rietveld phase analysis of X-ray diffraction pattern revealed completely formed MgB2 with a low amount of MgO. MgB2 bulk prepared of boron ultra-sonicated in ethanol for 15 min showed self-field Jc of around 300 kA/cm2 at 20 K without any compromise in Tc (~39 K). Pinning analysis based on Dew-Hughes expression showed major pinning contribution from grain-boundary pinning (~95.5%), along with a slight contribution from point pinning (4.5%). The microstructure study detected a system of large MgB2 grains (hundreds nm large) and 10–20 nm sized particles, possibly Mg-B-O, formed at MgB2 grain boundaries.

Solid-phase equilibria in the Tm–Te system and the thermodynamic properties of thulium tellurides are studied via electromotive force (EMF) method and X-ray phase analysis. Experimental data show that compounds TmTe, Tm2Te3, and TmTe3 form in the system. The partial thermodynamic functions of TmTe and Tm in alloys are found for the first time from EMF measurements in concentration cells, relative to TmTe and Tm electrodes at 300–450 K, from which standard thermodynamic functions of formation and standard entropies of intermediate compounds are calculated.

Additive manufacturing (AM) of the nickel-titanium (NiTi) shape memory alloys (SMA) have provided novel component solutions with a variety of design configurations in the industry. Electron beam melting (EBM) is a trending metal additive manufacturing process for industrial applications in the field of biomedical and aerospace engineering. In this study, experimental investigations were conducted to reveal the effect of processing conditions on the microstructure and hardness properties of EBM-fabricated nickel-titanium components. Furthermore, detailed microstructural characterizations were performed with a scanning electron microscope, EDS, and XRD for unveiling of the microscopic structure and phase analysis during the layer by layer solidification. The experimental results were systematically evaluated for the powder and the bulk prismatic components, respectively.

Yttrium-aluminum garnet (YAG) nanoparticles are synthesized by the coprecipitation of yttrium and aluminum hydroxides in a microreactor with freely impinging jets, followed by the thermal treatment of the coprecipitation products. According to the results of X-ray phase analysis, the coprecipitated hydroxides are X-ray amorphous. Analysis of the product of the thermal treatment of hydroxides at 1000°C for 10 min indicates the formation of Y3Al5O12 crystals. The method developed by us makes it possible to carry out the synthesis quickly, ensures low energy consumption, does not require laborious operations, and is technologically advanced and easily scalable.

This paper presents the formulation of fly ash (FA) geopolymer and the incorporation of ladle furnace slag (LFS) as a replacement to FA in geopolymer formation. The formulation of the LFS replacement was set at 10–40 wt.%. The geopolymer was formed by mixing FA and LFS with a sodium-based alkali activator. The FA geopolymer had a compressive strength of 38.9 MPa with the optimum formulation of 8 M NaOH concentration, AS/AA ratio of 3, and AA ratio of 1.5. The compressive strength was affected more significantly by the amorphous content. The most influential factors affecting the properties of FA geopolymer were: AS/AA ratio > AA ratio > NaOH concentration. Replacing LFS led to very little (4.1%) increment in the compressive strength. The LFS had little contribution in supplying Si, Al and Ca for the formation of the N-A-S-H and C-A-S-H network. But LFS acted as a filler and improved the compactness of the FA geopolymer. The mechanical performance of FA/LFS geopolymer was not governed by the amorphous content like the FA geopolymer, as LFS addition contributed to increasing crystalline content. New crystalline phases of calcite and CSH due to the addition of LFS helped to retain the compressive strength of FA geopolymer. Nevertheless, the outcome of the study proved that LFS can be blended with FA to produce geopolymers without severe deterioration in mechanical strength. LFS can be potentially added in geopolymers as filler to produce geopolymer mortar.

The aim of this study is to produce highly dense Si3N4 based composites with good mechanical properties and bioactivity. Si3N4 ceramics without using sintering aids, Si3N4-HA and Si3N4-HA-GNP based composites have been produced by spark plasma sintering (SPS) at temperatures of 1525–1550°C. The effect of reinforcement type and content on the densification behavior, phase analysis, microstructural development, mechanical properties, and in-vitro bioactivity behavior of Si3N4 were systematically investigated. Monolithic Si3N4 that contains a high amount of β-Si3N4 phase (~87 wt%) was produced by nearly full densification (~99%). Hydroxyapatite (HA) was used as a starting powder during the preparation of binary and triple composites to provide bioactivity to Si3N4, and after sintering, HA transformed into tricalcium phosphate (β-TCP and α-TCP) polymorphs. The incorporation of GNPs had a positive effect on the stability of β-TCP phases at higher sintering temperatures. The improvement in indentation fracture toughness of the samples with GNP reinforcement was mainly attributable to pull-out and crack deflection mechanisms. In-vitro bioactivity of GNP added composites enhanced with increasing α-TCP content. More calcium phosphate-based particle formation was observed in Si3N4-HA-GNP composites compared to the Si3N4-HA.

We report a refractive index tip fiber optic sensor based on a modal interferometer coated with a thin copper film. This device can be used for solute concentration in aqueous mixture measurement. The copper film increases the device reflectivity and, as a result, increases the multimodal interference pattern visibility. To validate the sensor device, different water-glycerol weight concentrations were used in the range from 0 to 45 Glycerol %. The recorded spectral responses show a redshifting, and a sensitivity of 19 pm / (Glycerol % by weight) from 0 to 18 % and 4.7 pm / (Glycerol % by weight) from 18 to 45 % was achieved. Besides, using a phase analysis we calculated a sensitivity of -15 rad/RIU.

Al-doped ZnO (ZnO:Al) thin films are prepared by high-frequency magnetron sputtering method. The phase analysis and crystal structure refinement are performed using X-ray diffraction data. The mean...

We investigate the melting ranges of the base Zr–Si mixture (eutectic composition) depending on the content of the heterophase powder component in the ZrB2–ZrSi2–MoSi2 and the HfB2–HfSi2–MoSi2 systems in the amount of 30–90 wt % obtained by self-propagating high-temperature synthesis (SHS). The range of the melting point of the Zr–Si mixture was 1420–1440°C; addition of the ZrB2–ZrSi2–MoSi2 SHS powders resulted in an increase of the melting onset temperature Tm0 to 1460–1560°C and in the complete melting temperature Tmelt to 1480–1670°C. Addition of the HfB2–HfSi2–MoSi2 powders influenced only slightly the Tm0 value (1390–1430°C), but resulted in the increase in Tmelt to 1510–1550°C. The X-ray phase analysis shows that the remelted samples contain the following phases: ZrB2/HfB2, ZrSi2/HfSi2, MoSi2, and Si; here, the number of phases was directly proportional to the SHS powder content in the Zr–Si mixture. The ingots are characterized by a homogeneous structure consisting of the silicon matrix and ZrSi2/HfSi2 and MoSi2 grains, with inclusions of ZrB2/HfB2.

Self-propagating High-temperature Synthesis (SHS) process is used to prepare Aluminium dodecaboride (AlB12). The phase analysis results of preparing AlB12 with Al and B2O3 as raw materials show that under air and argon conditions, the self-propagating and acid-washed self-propagating powders all have α-Al2O3 impurities when Mg, Al and B2O3 are used as raw materials. The phase analysis results of the preparation of AlB12 show that under argon conditions, the self-propagating and acid-washed, self-propagating powder has un-removable MgAl2O4 impurities, and the root cause of the low purity of AlB12 prepared by the self-propagating method is the presence of un-removable impurities.

The present work deals with the microstructure, nanoindentation and wear behaviour of Inconel-718 (IN-718) specimens fabricated through laser-powder bed fusion (L-PBF). To ensure the improvement in...

This paper reports a study into the phase composition and microstructure of tungsten ore concentrate after carbon-thermal reduction at different O:C ratios in the charge. This is required for determining those indicators that reduce tungsten loss through the sublimation of oxide compounds when processing ore concentrates, as well as when using reduced tungsten-containing doping additives. The study results have established that the reduced tungsten concentrate at the O:C ratio in the charge within the interval of 1.33‒2.30 contained the phases of W, W2C C, C, WO2. The microstructure demonstrated a spongy and disordered character. Together with W, the Mo, Si, Ca, Al impurities were present in the reduced products. The main elements identified at the sites studied had the following limiting content,% by weight: O – 5.01–17.32; C – 0.84–4.23; W – 61.21–86.78; Mo – 1.57–7.51; Si – 2.07–9.06; Ca – 1.34–11.30; Al – 0.27–0.40. The micro-inclusions at the examined surface areas acquired different complex shapes. There were traces of the process of caking between the particles. The analysis of the resulting data has shown that the most preferred ratio of O:C in the charge was 1.65. In this case, there is no lack of carbon and there is a predominance of W in the phase composition with a relatively little manifestation of the W2C phases, carbon, as well as the residual part of WO2. The post-reduction of the oxide component would occur during the doping process. The sponge structure contributes to a higher dissolution rate compared to standard tungsten ferroalloys. Lack of compounds with a relatively high propensity for sublimation does not require any special conditions to prevent the loss of tungsten in the gas phase, which increases the degree of assimilation of the target element

We have studied the effect of heat treatment conditions on the size and number of pores in plasma-sprayed aluminum oxide parts. Samples 100 × 100 × 2 mm in dimensions have been characterized by X-ray computer tomography, qualitative phase analysis, and scanning electron microscopy. The results demonstrate that the number and size of pores vary nonmonotonically with increasing heat treatment temperature, which is due to the heating-induced polymorphic transformations of aluminum oxide, accompanied by changes in the average density of the material and the associated changes in its volume. The temperature dependences of the number of both small and large pores have extrema at ~1100°C. At this temperature, the number of small pores decreases drastically, whereas the number of large pores increases. Further raising the temperature to 1300°C leads to an inverse process: the number of small pores increases drastically, whereas the number of large pores drops sharply. This is due to the transformation of δ-Al2O3 into α-Al2O3, which occurs very rapidly and is accompanied by a large increase in the density of the material of the plasma-sprayed parts and its embrittlement.

Indefinite-chill materials are used as shell materials for cast work rolls for surface-critical applications in hot rolling mills. Besides a smooth surface quality, a low sticking tendency and low sensitivity against incidents in the rolling mill, the work rolls need the highest wear resistance possible. The microstructure of the indefinite-chill material consists of various carbides (cementite up to 40 area-%) and up to 5 area-% of graphite embedded in tempered martensite. To increase the wear resistance of this material group, the comparably soft cementite has to be replaced by more wear resistant carbides such as MC, M2C or M6C. This can be achieved by increasing the amount of carbide forming elements such as Nb, V, Mo, W or Cr. Nevertheless it is important to maintain a certain amount of graphite in the microstructure to avoid sticking to the rolled material and to lower the sensitivity against mill incidents. It is well known that high amounts of carbide forming elements limit the graphite precipitation and therefore a sophisticated alloying concept is required for this material type. Not only the effects of matrix elements such as Si, Mn, Ni and Co but also the effects of Cr, Mo, W, Nb and V were studied in an intensive research project. This work gives an insight in the results of the project based on the example of the effects of Si and Cr on the phase amounts and the composition of the cementite phase.

The study presents the results of the effect of nanomodifying additives (WC, WO3, mixtures of W and Ti carbides) on the strength properties of concrete. These admixtures were obtained from the wastes of hard alloy metals. Microstructural and phase analysis of nanomodificators was performed. The positive effect of the proposed additives on the strength properties of concrete has been established.

In the present work, CZTSe (Cu2ZnSnSe4) films were deposited by Thermal evaporation technique. The as deposited films were annealed at 450 °C for 10 min. To incorporate Sulfur in the CZTSe film and to replace some of the Se by S, the films (as deposited and annealed) were treated with Thiourea solution (1 Molar). Further the films were annealed at 450 °C for 10 min after the thiourea treatment. Finally the films were characterized for phase analysis using XRD and Raman. The composition analysis was done using EDXRF. The band gap of the film varies according to the S/Se ratio. Compositional analysis as obtained from ED-XRF, shows the required ratio of Cu/(Zn + Sn) 1 for all the films. The conductivity and mobility of the films changes with variation in sulfur and selenium ratio. The obtained electrical and optical properties of CZTSe absorber layer after thiourea treatment are suitable for device application.

The possibility of high electrical conductivity of dry sliding electrical contact against a molybdenum counterface was studied. It was found that metals W and Cu were not able to form a sliding electrical contact with high wear resistance at current density higher 100 A/cm2. The characteristics of the contacts of iron containing metals were slightly better than the contact characteristics of nonferrous metals owing to weaker adhesion. Using X-ray phase analysis, the absence of oxides in the sliding zone of nonferrous metals was shown. This led to their strong wear and low electrical conductivity of contact. In the contact zone of iron-containing samples, the formation of FeO was observed, which made it possible to reduce wear. This means that high electrical conductivity is unattainable in sliding with current collection against molybdenum.

Copper powder spraying is under study: the PMS-1 feedstock copper, the copper that is mechanically milled in a high-energy planetary mill, and the copper that is also spheroidized in a plasma jet. High-density copper coatings are obtained using a CCDS2000 detonation facility. The Vickers microhardness of coatings $$H_{{\mathrm V}_{0.1}}$$ , obtained from feedstock and mechanically milled copper powders, increases from 110 to 160 and from 150 to 185, respectively, and the microhardness of coatings from the spheroidized powder is $$H_{{\mathrm V}_{0.1}}=165$$ . An X-ray phase analysis is carried out, and the resulting data indicate that, during the spraying, the copper oxide is partially reduced.

This study is aimed at preparing and evaluating the plasma resistance of YAS (Y2O3-Al2O3-SiO2) coating layer with crystalline YAG phase contents. For this purpose, YAS frits with controlled phase contents are prepared and melt-coated on sintered Al2O3 ceramics. Then, the results of phase analysis of crystalline YAS coating layer are compared to that of YAS frits, and discussed with regard to the plasma resistance of the YAS coating layer. The phase contents of the YAS frit change in a manner different from that of the prepared YAS coating layer, presumably owing to the composition change of YAS frit during the melt-coating process. The plasma resistance of the YAS coating layer is shown to increase with the YAG phase contents in the coating layer. Comparing the weight loss of YAS coating layer with those of commercial Y2O3, Al2O3, and quartz ceramics, the plasma resistance of the prepared YAS coating layer is 8 times higher than that of quartz and 3 times higher than that of Al2O3; this layer shows 70 % of the resistance of Y2O3.

In this context, to scrutinize the treatment of nanofluid within a thermal unit equipped with turbulators, two-phase approach was implemented. Three cases were employed: helical tape (HT) (case I), Barrier helical tape (BHT) (Case II), Perforated BHT (Case III). The regime of fluid is turbulent which was modeled via K-ɛ method. The values of ΔP for case II are 1.36 and 1.4 times higher than case III at Re = 5000 and 20,000, respectively. With the enhance of Re, the maximum increment of Nu was reported for a third case in which 215.25% augmentation has been observed. Exergy loss has been scrutinized in current article to find the best design. Greater pumping power causes the radial flow to increase and more distortion occurs in isotherms which offer lower irreversibility and exergy drop. Second case has lowest exergy loss and can suggest obtaining the highest available work for the unit. At lowest Re, changing the configuration from case II to case I and III makes the exergy drop to augment about 20.46% and 8.87%. In addition, for the best case, augmenting Re leads to 81.35% reduction in exergy loss. The greatest impact of inlet velocity can be reached by considering case I.

Although some years have passed since the discovery of the ferroelectric phase in HfO2 and ZrO2 and their solid solution system HfxZr1–xO2, the details of the emergence of this phase are still unde...

A microwave (MW) method has been developed for the preparation of a ZnO/Ag nanocomposite using methods of chemical precipitation and decomposition of thermally unstable compounds. Chemical co-deposition is a simple and efficient method in comparison with other methods of obtaining a ZnO/Ag nanocomposite. The characteristics of the synthesized product were determined by differential thermal analysis (DTA), X-ray phase analysis (XRA), and scanning electron microscopy (SEM). The studies carried out show the effectiveness of MW treatment in the production of ZnO/Ag nanocomposites.

For the first time, the GeSb2Te4–PbSb2Te4 section of the GeTe–Sb2Te3–PbTe quasi-ternary system is investigated by complex methods of physicochemical analysis (differential thermal, microstructural, and X-ray phase analysis with microhardness measurement and density determination) and the phase diagram is constructed. It is established that the section is a partially quasi-binary section of the GeTe–Sb2Te3–PbTe quasi-ternary system. The GeSb2Te4-based region of the solid solution (15 mol % PbSb2Te4) is revealed. The congruently melting compound GePbSb4Te8 is formed with the ratio of the initial components 1:1. Single crystals of the GePbSb4Te8 quaternary compound are formed by the method of chemical transport reactions. The unit-cell parameters of the GePbSb4Te8 compound, which crystallizes in the orthorhombic crystal system, are determined: a = 5.06 A, b = 9.94 A, an c = 11.62 A. It is established by investigation of the temperature dependences of certain electrical parameters of the GePbSb4Te8 compound and (GeSb2Te4)x(PbSb2Te4)1 – x solid solution that the alloys have p-type conductivity.

We synthesized an intermetallic compound Gd2Co7 with Ce2Ni7- and the Er2Co7-type structures. Gd2Co7 with a Ce2Ni7-type structure was stable at 1523 K. The refined lattice parameters were a = 0.5026(1) nm and c = 2.4266(6) nm. The pressure-composition (P–C) isotherm of Ce2Ni7-type Gd2Co7 indicated that reversible hydrogen capacity reached 0.61 H/M (0.76 mass%), and two plateaus were observed in the absorption-desorption process. The crystal structures of both Gd2Co7H2.5 and Gd2Co7H5.5 were determined to be Ce2Ni7-type by X-ray diffraction. Gd2Co7 with Er2Co7-type structure is stable at temperatures below 1473 K. The refined lattice parameters were a = 0.5029(1) nm and c = 3.6403(9) nm. The determined crystal structure of Gd2Co7H2.3 and Gd2Co7H5.4 was Er2Co7-type. The P–C isotherm of Er2Co7-type Gd2Co7 was similar to that of Ce2Ni7-type Gd2Co7. In this study, the P–C isotherms of a polymorphic binary alloy with Ce2Ni7-type and Er2Co7-type structures were obtained for the first time.

A Nb-Cr-V-W-Ta high entropy alloy has been subjected to annealing treatment at 600, 700 and 800 °C in air for 6 hours. Five different phases have been identified based on their composition in the as received condition. The annealing treatment does not alter the phase analysis and compositions except for the W-rich phase where minor changes in the composition have been observed. This is considered as an experimental evidence of sluggish diffusivity associated with HEAs. Absence of phase transformation during the heating and the minimal changes in observed compositions of the phases is an indication of the resistance to diffusion offered by the elements of the high entropy alloy. Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and color X-ray elemental mapping have been used to conduct this research.

In the present study the transformation between Cu2SnS3, Cu3SnS4 and Cu4SnS4 compounds is analyzed by means of X-ray diffraction and Raman scattering spectroscopy. A detailed analysis of the X-ray diffractograms showed the dependence of formation of the indicated compositional phases from the [Cu]/[Sn] ratio, which was also correlated with the evolution of the Raman spectra. The results are complemented with the detailed analysis of microscopic Raman imaging. Finally, fingerprint Raman spectrum for each compositional polymorph is presented, which should exclude any misinterpretations during phase analysis in future works.

The traditional process of alumina production by acid method was to neutralize the aluminum chloride solution obtained by acid leaching for preparing aluminum hydroxide, and then calcined to produce alumina. This process not only had many processes, but also had high energy consumption. In this paper, the properties of alumina prepared by pyrolysis of aluminum chloride solution were studied by chemical composition analysis, XRD and SEM. Thermodynamics of the pyrolysis process was analyzed. The effects of temperature and time on the pyrolysis properties of aluminum chloride solution were investigated. The results showed that it would be completely feasible according to thermodynamic calculation of the pyrolysis reactions of aluminum chloride solution. Meanwhile with the increasing of temperature and pyrolysis time, the residual chlorine content decreased gradually, and the particle size of the product decreased and tended to be uniform. The prolongation of pyrolysis time promoted the pyrolysis process of aluminum chloride solution and contributed to the formation of Al2O3 phase.

Monoclinic zirconium dioxide compositions of formula ZrO2–Al2TiO5 containing 0, 2, and 3.5% Al2TiO5 are studied. The aim of the research is to study the effect of aluminum titanate additives on the parameters of the monoclinic zirconium dioxide crystal lattice and sintering of the resulting product. The formation of a solid solution of aluminum titanate in monoclinic zirconium dioxide is confirmed using SEM and x-ray phase analysis. Sintered products are made from monoclinic zirconium dioxide with aluminum titanate additives as a proof of concept.

To enhance the mechanical properties of Ni–WC coatings, the carbon nanotubes were used as reinforced materials by laser cladding. Optical microscopy (OM), scanning electron microscopy (SEM) with en...

Improvement of the physical and mechanical properties of hard alloys based on WC – Co widely used in manufacturing of structural and tool products nowadays results from the use of novel technologies providing formation of a homogeneous high-density structures. Slight deviations of the carbon content from the equilibrium state lead to the formation of brittle η-phases (in particular, Co3W3C) and, accordingly, to deterioration of the mechanical properties of the product. We present the results of studying the homogeneity of the phase composition of the samples of hard alloys WC + 10% Co, obtained using advanced technologies of plasma-chemical synthesis and spark plasma sintering (SPS). The layer-by-layer X-ray phase analysis revealed the heterogeneity of the phase composition in depth: the brittle η-phase (Co3W3C) appears at a depth of ≥100 μm and reaches a constant value of 18 ± 1 wt.% at >200 μm, which indirectly confirms the hypothesis of carbon diffusion from graphite punches contacting with the surface of sintered samples and makes it possible to expand the range of parameters affecting the process of spark plasma sintering.

Natural samples of exogenous silicites are investigated by a combination of physical methods (X‑ray phase analysis, atomic-force microscopy, optical microscopy, scanning electron microscopy, optical transmission). The samples contain a small amount (~1%) of water and consist of chalcedony nanoparticles with a size of 22–68 nm, which form a complex hierarchically organized structure.

OAbstract. One of the approaches that has been done to produce a better performance of an intermediate temperature solid oxide fuel cell (IT-SOFC) is by varying the synthesis methods. This paper focused on the proton conducting electrolyte in particularly barium cerate and barium zirconate system namely BaCe0.9Y0.1O3-δ (BCY) and BaZr0.9Y0.1O3-δ (BZY). Supercritical ethanol processing technique is one of the alternative synthesis routes that able to produce ceramics powder at lower calcination temperature. The samples were synthesized in High-Pressure-High-Temperature (HP-HT) Batch Wise reactor system using ethanol as reaction medium. XRD was used to study the structure of both samples and all the data were refined using Rietveld refinement method by X’pert Highscore software. VESTA software is used to observe the crystal structure for both BCY and BZY samples. Both BCY and BZY have 98.16% and 96.55% purity after being calcined at 700°C and 1100°C, respectively. This study showed that BCY has orthorhombic structure with lattice parameter a=8.76Å, b=6.24Å and c=6.21Å and BZY exhibited cubic structure with a=b=c, and a=4.194Å. It was observed that BCY synthesized by supercritical fluid (SCF) method at reduced calcination temperature exhibited an acceptable value of lattice paramter as compared to other method that used higher processing temperature.

Ni-coated mixed powders were synthesized via chemical co-precipitation and hydrogen thermal reduction. Ti(C,N)-based cermets were further fabricated using as-prepared Ni-coated mixed powders successfully. Phase analysis, microstructure characterization, and properties of synthesized powders as well as the as-sintered cermets were investigated using a variety of techniques, including XRD, SEM, EDS. The results exhibited that XRD patterns of present experimental cermets only showed two diffraction peaks that correspond to Ti(C,N) hard phase and nickel binder phase. Also, microstructures of as-sintered cermets were more uniform and finer than those of traditional cermets with the same nominal composition. Meanwhile, present cermets prepared using chemical-coated method had excellent mechanical properties.

Samples of tricadmium diarsenide with MnAs nanogranules (44.7 mol % MnAs) are synthesized. The morphology of the samples is studied by X-ray phase analysis and electron microscopy. The electrical properties of tricadmium diarsenide with MnAs nanogranules are studied in a range of temperatures of 77–372 K. It is found that the voltammetric characteristics are symmetrical relative to the inversion of the voltage sign at this temperature, and their deviation from ohmicity at a certain threshold voltage and decrease in the region of ohmicity with the growth in temperature are determined by the increase in the breakdown probability in a field above 5 × 104 V/m. © 2020, Pleiades Publishing, Ltd.