Bi Pb Research Articles

Type-II superconductivity at 9K in Pb–Bi alloy

In the present work, we report the synthesis of Pb–Bi alloy with enhanced Tc of up to 9K, which is higher than that of Pb. The alloy is synthesized via a solid-state reaction route in the vacuum-encapsulated quartz tube at 700°C in an automated furnace. The synthesized sample is characterized by X-ray Diffraction(XRD) and Energy dispersive X-ray analysis(EDAX) for its phase purity and elemental composition. Rietveld refinement of XRD reveals that the end product is a majority hexagonal Pb7Bi3, with minor rhombohedral Bi. The electronic transport measurement shows metallic behavior with the Debye temperature of 108K and a superconductivity transition temperature (Tc) below 9K, which is the maximum to date for any reported Pb–Bi alloy, Pb or Bi at ambient pressure. Partial substitution of Bi at the Pb site may modify the free density of electronic states within the BCS model to attain the optimum Tc, which is higher by around 2K from the reported Tc of Pb. The superconductor phase diagram derived from magneto-transport measurements reveals that the synthesized alloy is a conventional superconductor with an upper critical field (Hc2) of 3.9 T, which lies well within the Pauli paramagnetic limit. The magnetization measurements carried out following ZFC(Zero Field Cool) protocols infer that the synthesized alloy is a bulk superconductor below 9K. The isothermal M-H(Magnetization vs. Field) measurements performed below Tc establish it as a type-II superconductor. The specific heat capacity measurements show that the Pb–Bi alloy is a strongly coupled bulk superconductor below around 9K with possibly two superconducting gaps.

Efficient CO2 electroreduction to formate using Bi–Pb bimetallic catalysts with 2D vertical nanosheets

2D vertical Bi–Pb bimetallic nanosheets with an electron transfer effect were used to broaden the potential window of the CO2RR.

Ferroelectric relaxor behaviour in Bi and K/Na-substituted solid solutions of tetragonal tungsten bronze PbNb2O6

Lead metaniobate (PbNb2O6 or PNO) belongs to the tetragonal tungsten bronze (TTB) family. There are three polymorphic forms of PNO: tetragonal (stable at high temperature), rhombohedral (stable at room temperature), and the metastable orthorhombic phase, which has ferroelectric properties. The metastable orthorhombic phase is formed by quenching from the high temperature tetragonal phase due to the reconstructive/sluggish tetragonal to rhombohedral phase transition. A suitable ionic substitution can also lead to the stable ferroelectric orthorhombic phase. Stabilization of the ferroelectric orthorhombic phase by ionic substitution, and the formation of ferroelectric relaxors with increased amounts of dopants is hereby reported for the compositions Pb(1-x)Bi(x/2K(x/2)Nb2O6 and Pb(1-x)Bi(x/2)Na(x/2)Nb2O6. The solid solutions of PNO showed evidence of linked dielectric relaxation and ferroelectricity, validating the distinctive ferroelectric relaxor behaviour for the compositions Pb0.6Bi0.2K0.2Nb2O6 and Pb0.6Bi0.2Na0.2Nb2O6. As the concentrations of bismuth (Bi) and potassium/sodium (K/Na) dopants increased, the Curie temperature (Tc), or the temperature corresponding to the maximum dielectric permittivity (Tm), dropped. By using the Uchino-Nomura relation as a modification of the Curie-Weiss law, it was established that the Pb0.6Bi0.2K0.2Nb2O6 solid solution exhibit higher degree of diffuseness than Pb0.6Bi0.2Na0.2Nb2O6 at the transitions. The width of the ferroelectric hysteresis loop increased as the percentage of dopants increased, from x = 0.1 to x = 0.3. At x = 0.4, a narrow ferroelectric hysteresis loop and a frequency-dependent Tm abruptly formed, which is indicative of a ferroelectric relaxor.

EVIDENCES OF MINERAL MELTING IN THE ORES OF THE SVETLINSK GOLD DEPOSIT, SOUTH URALS, RUSSIA

For the large Svetlinsk gold deposit (South Urals) evidences of partial melting of minerals and possible participation of polymetallic melts in the concentration and redistribution of gold and other metals are given. Finding of bismuth and antimony minerals in ores, among which there are gold minerals new to the deposit (pampaloite, montbrayite and aurostibite), specific mineral intergrowths (polymineral Sb–Bi–Pb–Te–Ag–Au drop inclusions), enrichment of early sulphides with Low-Melting-point Chalcophile Elements (LMCE), high formation temperatures for ore assemblages (up to 400°C), as well as the occurring metamorphism of amphibolite facies indicate the possibility of the formation of such melts. Polymetallic melts at the deposit could be formed both by partial melting of early sulphides and directly from hydrothermal fluids. The signs of melting also include simplectites of calaverite and native gold in the marginal parts of the large montbrayite grain.

An analytical model for calculating tie-line critical temperature in ternary immiscible alloys

An analytical model for calculating the tie-line critical temperature (TtC) in ternary immiscible alloys is proposed in this study. The results of the TtC for Al–Pb–Sn and Al–Bi–Sn alloys calculated by using the proposed model show a favorable agreement with the results obtained from the CALPHAD method and the experimental data, which verifies the correctness of the model. Based on the proposed model, the tie-line critical temperatures of several alloy systems, such as Al–In–Pb and Al–Bi–Pb, are calculated. The characteristics of the tie-lines in the ternary immiscible system are analyzed and discussed. The results indicate that ternary immiscible alloys can be divided into two types according to their characteristics of the tie-lines. For type I, the tie-line is nearly parallel to the edge binary system. For type II, there is a certain or large angle between the tie-line and the edge binary system. The relationship between the parameters for representing the tie-line equation and the critical point composition (xC) is determined by fitting the linear and secondary polynomial functions.

Elucidating of the influence of tin and cadmium in the Bi–Pb alloy on its thermal and nuclear properties as a coolant in fast neutron reactors

The purpose of this research is to investigate the physical properties and shielding characteristics of prepared (Bi–Pb) and (Bi–Pb–Sn–Cd) alloys, to be used as a coolant in a liquid metal nuclear fast reactor. The physical properties density, kinetics and mechanism of melting applying the reverse Johnson–Mehl–-Avrami rule and reduced time plot were applied, showing that melting processes take place in two dimensions, enthalpy and heat capacity were measured on the other hand for the prepared alloys within the solid and liquid states, respectively. Moreover, the results indicated that the bulk density and melting temperature of (Bi–Pb–Sn–Cd) alloys are lower than (Bi–Pb) alloys. Likewise, the thermal properties of (Bi–Pb–Sn–Cd) alloys seemed more suitable applicants than that of (Bi–Pb) alloys. Additionally, eight different gamma-ray energy lines in the range 0.12178–1.40792 MeV were used to determine the mass attenuation for the alloy samples. Also, gamma radiation attenuation characteristics, the half-value layer and effective atomic number were determined using Phy-x/PSD software. Furthermore, three types of neutron energies (slow neutrons, total slow neutrons, as well as neutrons of energies greater than 0.4 eV) were used to determine the macroscopic neutron cross-sections for the prepared alloys. The calculated values of mass attenuation coefficients exhibited a very good agreement with the experimental values of those parameters. The values of neutron macroscopic cross sections at fast neutrons for (Bi–Pb) and (Bi–Pb–Sn–Cd) alloys are small, this means that there is no consequence on fast neutrons used in a nuclear breeder reactor. Finally, we may reach the conclusion that Bi–Pb–Sn–Cd alloys are a possible candidate to be used as a coolant in fast nuclear reactors, as well as it is most suitable as an outer cooling and shielding blanket vessel as well.

Influence of High Content of Sodium Doping in Bi(Pb)2212 Superconductors

We study here, the effect of high content of sodium doping on structural and electrical properties of Bi(Pb)2212 superconducting. The X-ray analysis results showed that all the prepared samples mainly belong to the superconducting tetragonal phase Bi–(Pb)2212. SEM micrographs show that the grains are closely related and have a characteristic flat shape for the superconductor Bi (Pb) 2212. For the undoped sample, the grains are randomly distributed with an average size of 5 μm. For doped samples, the morphology changes with sodium concentration. Resistivity measurements show that all samples have a superconducting character.

Effect of microwave melting and subsequent rolling on the corrosion behavior and electrochemical properties of an aluminum anode using response surface methodology

To obtain aluminum-air batteries with a high anodic efficiency and low corrosion rate, it is necessary to study the methods by which their aluminum alloy anodes are prepared. Here, the performance of an aluminum alloy anode was optimized by microwave melting and rolling. The aluminum anode showed the best performance under a 1000 W microwave power, two passes, and 40% reduction degree (sample denoted 1000W-2–40%). Under these conditions, the grain size of the Al–Zn–Bi–Pb anode was uniform, and no intergranular corrosion was observed. The corrosion resistance was high, and the anodic efficiency reached 72.72%. Finally, by observing the microstructure of an aluminum anode obtained under 1000 W microwave treatment, the corrosion mechanism was analyzed. The activity of the rolled aluminum anode was improved due to the existence of ZnAl2O4 phase. However, in 1000W-1–30%, 1000W-2–20%, and 1000W-3–30% samples, fine grains precipitated at high-angle grain boundaries. The grain orientation was mainly (110), which led to the intergranular corrosion of a large area of the anode, which made it unsuitable for use in aluminum-air batteries.

Investigation of Cr addition effect on structural, morphological, electrical and magnetic properties of Bi(Pb)-2212 superconductors

Investigation of Cr addition effect on structural, morphological, electrical and magnetic properties of Bi(Pb)-2212 superconductors

Enroute to sub-300 °C operating Sn–Zn||Pb–Bi liquid metal battery by compositional engineering

Liquid metal battery (LMB) is considered a potential contender for grid-scale energy storage systems. However, high operating temperatures (>400 °C) leading to higher operational costs limit its commercial application. Therefore, the current work focuses on reducing the melting temperature of electrodes and electrolytes below 300 °C by compositional engineering. Moreover, this study utilizes earth-abundant elements like Zn (with less reliance on Li), in Zn–Sn||Bi–Pb LMB system. The composition of LiCl in the electrolyte is varied to optimize the battery performance, especially the energy efficiency and overpotential while maintaining an operating temperature of <275 °C. It is found that as the LiCl content in the electrolyte salt increases (5–30 Mol%), the overpotential of the battery decreases (0.9–0.3 V), and the energy efficiency of the charge-discharge process improves (14.5%–80.9%) owing to the better ionic conductivity of LiCl. For the optimized LiCl concentration of 30 Mol% LiCl in the electrolyte, the fabricated LMB exhibit good cyclability (no degradation till 100 cycles), a high discharging voltage plateau of 0.92 V, 24.6 mAh charge storage capacity, and a low operating temperature of 275 °C, which is the lowest operating temperature reported so far in a Zn-based LMB system.

Structural reconstruction of BiPbO2Br nanosheets for electrochemical CO2reduction to formate

A Bi–Pb composite catalyst with heterogeneous interfaces obtained by electroreduction of BiPbO2Br nanosheets exhibits impressive performance for CO2reduction to formate.

Molecular dynamics study of corrosion behavior of iron with vacancies exposed to lead‐bismuth eutectic

AbstractThe corrosion behavior of iron with vacancies in a liquid lead‐bismuth eutectic environment is simulated by molecular dynamics with embedded‐atom model potential at 700–1073 K. The vacancy is substituted into Fe crystal with the percentage of 0%, 0.2%, 0.4%, 1.0%, and 2.0% to investigate the effect of the vacancy on the corrosion behavior of iron. By evaluating the time‐dependences of penetration depths and the number of penetrating Pb and Bi atoms and also observing the trajectory of a penetrating Bi atom, we concluded that temperature and vacancy will enhance the corrosion behavior of iron in liquid lead‐bismuth, and the corrosivity of Bi atom is larger than that of Pb atom. The result is supported by the calculated substitutional energies of each Pb or Bi atom with a Fe atom or vacancy, which are in the order of . If there are vacancies in the iron bulk, the Bi atom and Pb atom will preferentially penetrate the bulk through the vacancies, and the Bi atom has another way to penetrate into the bulk by substituting the Fe atom layer by layer. The present study provides new insight into challenges related to the corrosion behavior of iron‐based materials with vacancy‐type defects.

New experimental studies on the phase relationship of the Bi–Pb–Te system

Knowledge of the phase relationships is crucial in developing thermoelectric materials and allows a better understanding of the properties of the relevant systems. In the present work, we present the liquidus projection of the Bi-Pb-Te system and phase equilibria of the BiTe-PbTe-Bi2Te3 portion at 400 and 520 °C. Alloys were prepared by melting high-purity elements in cleaned quartz tubes and their microstructures were characterized by scanning electron microscopy, electron probe microanalysis, wavelength-dispersive X-ray spectrometer, X-ray diffractometry and differential scanning calorimetry. The binary compound BiTe extends up to 16.7 at.% Pb along BiTe-PbTe at 520 °C. The solubilities of Bi in PbTe were established to be 3.6, 3.8 and 10.8 at.% at 360, 400 and 520 °C, respectively. This work will help to understand the microstructure evolution during preparation and service and promote the designing of the Bi–Pb–Te-based high-performance materials.

Multi-stage ore forming history of the Variscan porphyry Mo-Cu-W Myszków deposit (Poland): Evidence from trace elements of pyrite

Four generations of pyrite (Py I-IV) from the porphyry-type Mo-Cu-W Myszków deposit are investigated using electron-probe microanalysis and laser ablation inductively coupled plasma mass spectrometry. Pyrite-I, representing skarn-forming stage of mineralization associated with magma intrusion activity, was formed in a relatively high-temperature environment. It has high contents of Co (up to 3966.11 ppm), Ni (up to 2552.62 ppm), Mn (up to 70.32 ppm), and Se (up to 103.94 ppm), but is depleted in As, Te, V, and devoid of Sb. Pyrite-II, representing the main hydrothermal stage of ore mineralization under the vigorous boiling conditions, contains elevated levels of Co (up to 1962.31 ppm), Ni (up to 1080.86 ppm), and Se (up to 153.03 ppm) with a high Se/Te ratio of 28.30. Pyrite-III, formed under vigorous to gentle boiling conditions, is also enriched in Co (up to 3312.65 ppm), Ni (up to 1469.09 ppm), Se (up to 184.24 ppm), and Te (up to 117.50 ppm), but depleted in As, Mn, V. The latest, low-temperature generation of pyrite, Py-IV is characterized by the highest contents of As (up to 3331.79 ppm), Mn (up to 141.91 ppm), the elevated levels of Te (up to 62.51 ppm), but depletion in Co, Ni, Se, V. Cu (mostly Py-I and Py-II), Pb (mainly Py-II and Py-IV), Bi (mainly Py-IV), Ag and Au (mainly Py-IV) are found as trace elements of solid micro-sized inclusions hosted by various generations of pyrite. The results of the study seem to demonstrate the sequence of metal precipitation in the ore system. At the relatively high-temperature conditions (the contact metamorphism down to hydrothermal stage), the deposition of Co, Ni, Mn, and later Se in pyrite occurred. Additionally, cobalt and nickel concentrations might suggest a contribution from magmas of mafic composition. Copper was mobilized and formed solid micro-inclusions in the host pyrite. Later, along with the evolution of the ore-forming system, and lower temperature rate, tellurium entered the structure of pyrite, when the redox condition temporarily changed from oxidizing to more reducing. With the further temperature drop and likely rising oxidation, arsenic entered the pyrite structure in the most recent episode of the main hydrothermal ore-mineralization stage. Also, the highest budget of Bi, Pb, and Ag with traces of Au was deposited as micro-inclusions in pyrite during this period. The concentration of these elements can be related to the same mechanism, as revealed by their positive correlations, i.e. Bi vs Pb in Py-IV (R = 0.95) Ag vs Pb in Py-IV (R = 0.94), Ag vs Bi in Py-IV (R = 0.97).

Accurate determination of Pb and Bi contents and Pb isotopic composition in geological and cosmochemical samples by inductively coupled plasma quadrupole mass spectrometry

A method for accurately determining Pb and Bi contents in geochemical and cosmochemical solid samples using inductively coupled plasma quadrupole mass spectrometry (ICP–QMS) is described. Pb and Bi contents are determined using isotope dilution and calibration methods, respectively. For this purpose, an accurate determination scheme of Pb isotopic ratios is established using standard-sample bracketing and matrix-matching methods due to the significantly differences of Pb isotope ratios in commercial standard solution, geochemical and cosmochemical samples. Lead is chosen as the most appropriate internal standard element to reduce the matrix effect when determining Bi content. Our developed analytical procedure was applied to geological and cosmochemical reference samples to evaluate the accuracy of our data. The Pb isotopic composition data obtained from this study are in good agreement with the literature values obtained using multicollector inductively coupled plasma mass spectrometry and thermal ionization mass spectrometry, which ensures the accuracy of the Pb isotopic ratios obtained by our method. The Bi content data obtained from this study for a cosmochemical sample are in excellent agreement with neutron activation values in literature.

Synthesis of high-temperature superconducting ceramics in the Bi(Pb)-Sr-Ca-Cu-O system based on amorphous precursors

The paper presents the results of the synthesis of bismuth superconducting ceramics with compositions Bi1.6Pb0.4Sr2Can-1CunOy (n=2, 3, 5) based on amorphous ceramics obtained by ultrafast melt quenching. In order to increase the rate of formation of superconducting compounds, effective devices have been developed for melting and hardening melts under the action of IR radiation. The sample holder was made of platinum. Melting and hardening were carried out in a continuous mode in an oxidizing environment in a flowing air atmosphere. The study of the elemental composition of the precursor samples established a slight deviation towards a decrease in the cationic composition of the precursors (Bi, Pb and Ca), relative to the stoichiometric composition. An increase in oxygen content by 12–15 % was also found. Synthesis of superconducting compounds was carried out in the temperature range of 843–850 °C, depending on the composition. The study found that in the sample Bi1.6Pb0.4Sr2Ca4Cu5Oy (2245) the superconducting high-temperature phase 2223 crystallizes. It was found that the formation of the superconducting phase 2223 in the Bi1.6Pb0.4Sr2Ca4Cu5Oy composition occurs in a lower and wider temperature range (843–848 °C) compared to the Bi1.6Pb0.4Sr2Ca2Cu3Oy (2223) composition. The complete formation of the superconducting high-temperature phase 2223 in a sample with the nominal composition Bi1.6Pb0.4Sr2Ca2Cu3Oy (2223) was carried out in a narrow temperature range of 849–850 °C, in a strict temperature regime with the participation of the liquid phase. An increase in the rate of formation of the superconducting compound 2223 in both studied compositions by 1.5–2.5 times was established, compared with the solid-phase method and other melt methods

Impact of Ca(BO2)2 Doping on High-Tc Phase Formation and Transport Properties of Bi(Pb)-2223 Superconductor

Proper Doping of a high-temperature superconductor (HTS) Bi(Pb)-2223 is an effective route to prepare Bi(Pb)-2223 HTS with enhanced transport characteristics. In this paper, we studied the impact of Ca(BO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> doping on high-T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> phase formation kinetics and transport critical current density of Bi(Pb)-2223. Samples with a nominal composition of Bi <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1.7</sub> Pb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.3</sub> Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> Ca <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2-x</sub> Cu <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</sub> [Ca(BO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ] <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</sub> , x = 0 −0.15 were prepared by the solid-state reaction method. The phase evolution of the prepared materials was studied by X-ray diffraction analysis (XRD). The resistivity and critical current density were measured by the standard four-probe method. Scanning electron microscopy (SEM) combined with Energy Dispersive X-ray (EDX) microanalysis (SEM-EDX) was used to examine the microstructure and elemental composition of samples. The obtained results show that Ca(BO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> doping leads to the promotion of the high-T <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> phase formation and enhancement of the transport critical current density ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J_c)</i> in Bi(Pb)-2223 HTS.

Nanostructured Low-Resistance Ceramics Based on the Bi–Pb–Sr–Ca–Cu–O System Produced by Solar Technology

Nanostructured Low-Resistance Ceramics Based on the Bi–Pb–Sr–Ca–Cu–O System Produced by Solar Technology

Effects of TiO2 nanoparticle addition on the flux pinning properties of the Bi1.6Pb0.4Sr2Ca2Cu3O10+δ ceramics

The effects of adding TiO2 nanoparticles on the flux pinning properties of the Bi–Pb–Sr–Ca–Cu–O (BPSCCO) system were investigated. Polycrystalline samples of (Bi1.6Pb0.4Sr2Ca2Cu3O10+δ)1-x(TiO2)x, where x = 0.000, 0.002, 0.004, 0.006, 0.008, and 0.010, were fabricated by the conventional solid-state reaction method. The X-ray diffraction (XRD) results showed that all samples consisted of Bi-2223 and Bi-2212 phases. The Bi-2223 volume fraction decreased with the addition of TiO2. Scanning electron microscopy (SEM) examination presented a degradation in texture structure with increasing misoriented grain and porosity with high doping contents. The critical temperature was decreased by TiO2 appearance in relation to Bi-2223 deceleration. Critical current density dependence on the magnetic field Jc(B) was enhanced with x = 0.002, 0.004 and reached maximal values on the x = 0.002 sample. In the collective pinning theory framework, the small bundle field (Bsb) and the large bundle field (Blb) were estimated, revealing the extension of the small and large bundle regimes with proper amounts of dopant. The temperature-dependent normalized critical current density (j) indicated that δl pinning is the dominant flux pinning mechanism in all samples. The Dew-Hughes model analyzed the pinning center properties and confirmed that TiO2 nanoparticles create normal core point pinning centers in the matrix.

Synthesis of Bi–Pb–Sn–Cd solder particles for joining Ag-plated PZT ceramics at 100 °C

Synthesis of Bi–Pb–Sn–Cd solder particles for joining Ag-plated PZT ceramics at 100 °C