Sn Bi Research Articles

Mineralogy of the scheelite-bearing ores of Monte Tamara, SW Sardinia: insights for the evolution of a Late Variscan W–Sn skarn system

AbstractSouthwestern Sardinia, Italy, hosts several skarn, W–Sn–Mo greisen and hydrothermal deposits related to a 289±1 Ma Late Variscan granite suite. Among them, the most representative scheelite-bearing skarns belong to the San Pietro and Sinibidraxiu localities, in the Monte Tamara area, Sulcis region. The San Pietro deposit is a typical calc-silicate skarn whereas Sinibidraxiu is a sharply bounded orebody hosted in a marble unit. Optical petrographic observations and compositional data of major and trace elements were obtained for samples from both localities. San Pietro data suggests evolution from an oxidising prograde skarn stage (andradite–diopside, hematite and scheelite), to progressively more reducing conditions from the early retrograde (magnetite–cassiterite) to the late sulfide stage (arsenopyrite, stannite, molybdenite, Bi sulfosalts and Zn–Cu–Pb–Fe sulfides); Sinibidraxiu has diffuse carbonate–quartz intergrowths pseudomorphic over an early mineral assemblage with fibrous habit, followed by abundant ore mineral precipitation under reducing conditions (scheelite, arsenopyrite and Pb–Zn–Cu–Fe sulfides). Geothermometers indicate a comprehensive temperature range of 460–270°C for the sulfide stages of both deposits. The differences between the two deposits might be controlled by the distance from the source intrusion coupled with the different reactivity of the host rocks. The San Pietro mineralogy represents a more proximal skarn, contrasting with more distal mineralogical and chemical features characterising the Sinibidraxiu orebody (lack of Mo–Sn–Bi phases; LREE–MREE–HREE signature of scheelite). This investigation contributes for the first time to the identification of a W–Sn skarn system in SW Sardinia, thereby suggesting the Monte Tamara area and its surroundings as favourable for further exploration.

Effect of nano-phased bismuth–tin alloy surface coating on tribo-mechanical properties of basalt fiber reinforced composites

A novel method for coating basalt fiber with a eutectic bismuth–tin (Bi–Sn) mixture was developed. Bi-Sn nanoparticles were synthesized using a sol-gel process and deposited on basalt fiber by chemical vapor deposition, with the aim of evaluating the tribo-mechanical properties of the final epoxy-composite material. X-ray diffraction showed that the synthesized Bi–Sn alloy was highly polycrystalline with equal distribution of tetragonal and orthorhombic Bi–Sn polymorph phases with crystallite sizes between 17 and 55 nm. High-resolution electron microscopy revealed that the sample possesses highly fused, flake-stacked planar layers, with 50 nm-thick flakes of variable length. Elemental analysis determined that the alloy contains 57% Bi (at.wt%), and Raman spectroscopy confirmed the characteristic Bi–Sn fingerprint peaks of 148, 201, and 397 cm−1. Thermal analysis of the composites showed good thermal stability with only 4% mass loss at 700 °C. Furthermore, an increase in the Bi–Sn loading enhanced the tribo-tensile properties. It was found that at a Bi-Sn gravimetric loading of 0.2 g the composite yielded the highest ultimate tensile strength of 303 MPa compared to the reference (154 MPa), even as the Young's moduli showed a decrease in elasticity by up to 24.99%. Moreover, the tribology results showed a good friction coefficient (0.5), with a negligible wear rate (4.53 × 10−8 mm3/Nm) and relatively low wear volume (0.118 mm3). Thus, the proposed method resulted in alloy composites with improved tribo-mechanical properties, and has potential applicability in the development of lead-free solders.

Construction of Sn-Bi-MOF/Ti3C2 Schottky junction for photocatalysis of tetracycline: Performance and degradation mechanism

In this study, Sn–Bi–MOF/Ti3C2 heterojunction catalysts were prepared using the solvothermal method, and their photocatalytic ability to degrade and mineralize tetracycline (TC) under illumination was investigated. After 90 min of photocatalysis, the pollutant had a degradation efficiency of 96.2% and a mineralization rate of 45.5%. The physicochemical properties of the catalysts were analyzed using various methods. The effects of the solution pH, coexisting anions, and water quality on the catalyst performance were investigated. ·O2− and h+ are the main active substances in the photocatalytic mechanism, as demonstrated by free-radical quenching experiments and EPR tests. The degradation of TC and the intermediates produced were determined using 3D fluorescence and LC-MS. The photocatalytic mechanism of Sn–Bi–MOF/Ti3C2 was proposed based on free radical determination and electrochemical tests. The formation of the Schottky junction accelerated the transfer of electrons to Ti3C2 and improved the separation of charges, which led to the generation of free radicals. Sn–Bi–MOF/Ti3C2 still exhibited good catalytic ability after four cycles of the experiments, and the XRD patterns before and after the reaction were consistent, which illustrates that the composite structure was stable. Overall, Sn–Bi–MOF/Ti3C2 has promising applications in the photocatalytic removal of refractory pollutants.

Bubbling phenomenon of liquidized Sn–Bi–Li–Er alloy under hydrogen plasma exposure

A laboratory-scale inductively coupled plasma apparatus investigated the behavior of liquid Sn–Bi–Li–Er alloy (SBLE) under hydrogen (H2) plasma exposure. By exposing the liquid SBLE to H2 plasma, the bubbling of liquid SBLE and pulsive H2 pressure increase was observed. Moreover, plasma density, i.e. ion flux, increased both bubble size and H2 pressure spike. The simultaneous measurement of a high-speed camera and mass spectrometry concluded that the bubble was formed by H2 accumulation, and ∼38% of hydrogen ion flux contributed to the H2 accumulation. Lithium hydride may be considered the bubble sphere’s origin from X-ray photoelectron spectroscopy measurement of droplets produced from the ruptured bubble sphere. From the experimental results, the bubble formation mechanism was discussed.

Effect of cobalt nanoparticles on mechanical properties of Sn–58Bi solder joint

Effect of cobalt nanoparticles on mechanical properties of Sn–58Bi solder joint

Effects of tin particles addition on structural and mechanical properties of eutectic Sn–58Bi solder joint

Effects of tin particles addition on structural and mechanical properties of eutectic Sn–58Bi solder joint

Sn–Bi bimetallic interface induced by nano-crumples for CO2 electroreduction to formate

Sn–Bi bimetallic interface induced by nano-crumples for CO2 electroreduction to formate

Microstructural analysis and thermal conductivity of the Ag–Bi–Sn alloys

Structural and thermal properties of five Ag–Bi–Sn ternary alloys with tin content ranging from 12.8 to 75.1 mass% and nearly equal mass contents of silver and bismuth were investigated in this study. Microstructures and melting properties of as-solidified alloy samples were examined using scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS), X-ray diffraction (XRD) analysis, and differential thermal analysis (DTA) in combination with the CALPHAD (CALculation of PHase Diagram) method. The observed microconstituents were Ag3Sn, (Sn) and, (Bi) phases as well as ternary (Sn)+(Bi)+Ag3Sn eutectic. The measured temperature of the ternary eutectic reaction was 138.0°C.The flash method was used for thermal diffusivity measurements in the temperature range from 25 to 100°C. Based on the measured values of thermal diffusivity, thermal conductivity of the solid Ag–Bi–Sn alloys was obtained. Thermal conductivity of the studied Ag–Bi–Sn ternary alloys considerably increases with increasing tin concentration and slightly decreases with increasing temperature.

Alloying regulation mechanism toward microstructure evolution of Sn-bi-based solder joint under current stress

Sn–Bi-based solder alloys have triggered substantial concern in development of low-temperature interconnecting materials of multi-level packaging electronic devices. However, with the high-density current treatment, dramatic atom migration occurs in Sn–Bi-based solder joint, which accelerates the evolution of solder joint microstructure, including the aggregation of Bi phase and the excessive growth of interfacial intermetallic compound (IMC). In this work, Sb element shows a unique influence mechanism on the electromigration (EM) resistance of Sn-Bi-based solder joint. Doped Sb in Sn58Bi-1Sb (SB-Sb) solder massive precipitate as Sn-Sb and Bi-Sb nano precipitations under current stress. These nano precipitates show the ability to capture the migrating atoms, inhibit the migration of Bi atoms and Sn atoms, and enhance the EM resistance of solder joint. Importantly, Bi twin crystal structure is observed in Sn-Bi-Sb solder for the first time. The variation of twins' phase orientations in different positions of solder joint is associated with atomic migration paths induced by the current stress and would eliminate the overgrowth of the Bi rich phase and IMCs. The presented study provides the valuable insights into the regulates mechanism of alloy elements on atom migration in Sn-Bi-based solder joint.

Revealing the deformation behavior and resultant texture evolution in extruded dilute Mg–Bi–Sn–Ca alloy during hot compression

In this paper, the deformation behavior and resultant texture evolution of an extruded dilute Mg-0.5Bi-0.5Sn-0.5Ca (BTX000) alloy during hot compression with different strain rates were studied. The results indicated that the activation of twins and dynamic recrystallization (DRX) are greatly dependent on the strain rates. The critical shear stress (CRSS) of twinning ranged from 66 to 197 MPa at different strain rates. In the case of strain rate of 3.3 s −1, the largest CRSS value led to the lowest area fraction of twins and the strongest texture intensity. In addition, the DRX extent increased with the increased strain rate. This phenomenon was caused by the variation in local stress concentration due to the different degrees of dislocation accumulation generated at different strain rates. More specifically, the dominant DRX mechanism at low strain rates was CDRX, while at high strain rates, the dominant DRX mechanisms were CDRX and twin-induced dynamic recrystallization (TDRX). Furthermore, the activation of twinning and DRX process altered the crystal orientation from favorable for basal slip to non-basal slip. This shows that, in addition to twinning, non-basal dislocation slip could be activated, and it plays an important role in plastic deformation behavior of extruded BTX000 alloy. The experimental results of this study provide new insight for further improving the plastic deformation ability of dilute Mg alloy.

Bi and Sn Doping Improved the Structural, Optical and Photovoltaic Properties of MAPbI3-Based Perovskite Solar Cells

One of the most amazing photovoltaic technologies for the future is the organic–inorganic lead halide perovskite solar cell, which exhibits excellent power conversion efficiency (PCE) and can be produced using a straightforward solution technique. Toxic lead in perovskite can be replaced by non-toxic alkaline earth metal cations because they keep the charge balance in the material and some of them match the Goldschmidt rule’s tolerance factor. Therefore, thin films of MAPbI3, 1% Bi and 0%, 0.5%, 1% and 1.5% Sn co-doped MAPbI3 were deposited on FTO-glass substrates by sol-gel spin-coating technique. XRD confirmed the co-doping of Bi–Sn in MAPbI3. The 1% Bi and 1% Sn co-doped film had a large grain size. The optical properties were calculated by UV-Vis spectroscopy. The 1% Bi and 1% Sn co-doped film had small Eg, which make it a good material for perovskite solar cells. These films were made into perovskite solar cells. The pure MAPbI3 film-based solar cell had a current density (Jsc) of 9.71 MA-cm−2, its open-circuit voltage (Voc) was 1.18 V, its fill factor (FF) was 0.609 and its efficiency (η) was 6.98%. All of these parameters were improved by the co-doping of Bi–Sn. The cell made from a co-doped MAPbI3 film with 1% Bi and 1% Sn had a high efficiency (10.03%).

Microstructure and mechanical properties of Sn–Bi solder joints reinforced with Zn@Sn core–shell particles

Microstructure and mechanical properties of Sn–Bi solder joints reinforced with Zn@Sn core–shell particles

Dynamic recrystallization behavior and strengthening mechanism of quasi-precipitate-free dilute Mg–Bi–Sn alloy

In this study, a dilute Mg–0.5Bi–0.5Sn alloy system was designed and subjected to extrusion at a low temperature of 250 °C. The dynamic recrystallization behavior and strengthening mechanism of the extruded alloy were discussed in detail. At the initial stage of the extrusion process, the dynamic recrystallized grains were formed through twinning-induced dynamic recrystallization (TDRX), continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). In the middle stage of extrusion, the emergence of CDRX and DDRX were synergistic. In the later stage of extrusion, DDRX and CDRX were exclusive and DDRX was the dominant mode. For the dilute extruded Mg–0.5Bi–0.5Sn alloy, the ultimate tensile strength, tensile yield strength and elongation were 282 MPa, 212.4 MPa and 36.3%, respectively, reaching an excellent high strength-ductility balance. The enhanced strength has been an outcome resulting from grain boundary strengthening and texture strengthening, along with dislocation strengthening. Ductility enhancement is closely related to the easily activation of <c+a> slips, which can be ascribed to the relatively high Schmid factor.

Investigation of Sn–Bi–In ternary solders with compositions varying from Sn–Bi eutectic point to 76 °C ternary eutectic

Investigation of Sn–Bi–In ternary solders with compositions varying from Sn–Bi eutectic point to 76 °C ternary eutectic

Board Level Drop Test for Evaluating the Reliability of High-Strength Sn–Bi Composite Solder Pastes with Thermosetting Epoxy

The Sn–Bi solder paste is commonly used in electronic assembly and packaging, but its brittleness causes poor reliability in shock environments. In this study, the mechanical reliability of Sn–Bi solder paste and Sn–Bi composite solder paste with thermosetting epoxy (TSEP Sn–Bi) was investigated with the board level drop test. The crack characterizations of solder joints were evaluated using a stereomicroscope after the dye and pull test. The microstructure characterization and failure types of solder joints were analyzed by a scanning electron microscope (SEM), and an energy dispersive spectrometer (EDS) was employed to investigate the initial phase identification and elemental analysis. Compared with Sn–Bi solder paste, the results show that the TSEP Sn–Bi solder pastes reduced the proportion of the complete failure and partial failure of the solder joints during the drop test. The microstructure observation of the crack path showed that the Sn–Bi/TSEP Sn–Bi solder joints were reinforced through the cured epoxy resin. The number of drops of the Sn–Bi/TSEP Sn–Bi-x (x = 3, 5, 7) solder joints had 1.55, 2.57, and over 3.00 times that of Sn–Bi/Sn–Bi solder joints after the board level drop test.

High-strength Sn–Bi-based low-temperature solders with high toughness designed via high-throughput thermodynamic modelling1

Low-temperature Pb-free solders are in demand in the electronic industry for reducing processing emissions and enhancing product reliability. Sn–Bi-based alloys have drawn great interests. We performed high-throughput CALculation of PHAse Diagram modelling and systematically screened 35,343 alloy compositions among the Sn–Bi–Ag–In and Sn–Bi–Ag–Zn quaternary systems. An optimal alloy of each system was proposed, experimentally characterised based on microstructural, thermal, and mechanical analyses, and their phase equilibria and solidification reactions are elaborated. The designed Sn–Bi–Ag–In alloy with solidus and liquidus temperatures of 137.6 and 157.1°C, respectively, shows superior mechanical properties, e.g. the ultimate tensile strength of 57 MPa, elongation of 50%, and toughness of 20.6 × 106 J m−3, which is a promising material for low-temperature interconnection.

Self-healing action of Bi in high-performance Sb–Bi–Sn positive electrodes for liquid metal batteries

Li||Sb–Bi–Sn liquid metal batteries (LMBs) have comprehensive advantages of a high energy density, excellent rate capability, low material costs, and high cycle performance. However, the corrosion of the positive electrode to the current collector at high temperatures cannot be neglected over the long term. Here, we investigate the corrosion behavior of SS304 in two types of Sb–Bi–Sn alloys under static and cell cycling conditions. Interestingly, we find that the cell performance of Li||Sb–Bi–Sn LMBs are not affected by corrosion between the positive electrode and stainless-steel current collector. The corrosion products and their participation in the cell reaction process are determined using ex situ analyses and electrochemical measurements. Bi not only inhibits the dissolution of SS304 in Sb–Bi–Sn alloy but also spontaneously promotes the decomposition of Fe–Sb and Fe–Cr–Sb corrosion products during lithiation, releasing the active component Sb, and Sb–Bi–Sn alloy is recovered. Encouragingly, even in the event of corrosion, the cell capacity, efficiency, and cycle stability remain almost unaffected due to this self-healing action of Bi. This study represents a new direction toward inhibiting the corrosion of positive electrode and stabilizing cell performance for practical application and commercialization by alloying.

Insight on the correlation between bimodal-sized grain structure and tensile properties of extruded low-alloyed Mg–Sn–Bi–Mn alloy

In this study, a novel low-alloyed Mg–2Sn–2Bi-0.2Mn (wt.%) alloy is designed and extruded successfully at 523 K. Microstructural analysis reveals that a bimodal-sized grain structure is obtained due to the abnormal dynamic recrystallized (DRXed) grain growth. The results indicate that the studied alloy exhibits a good balance between strength and ductility with a tensile yield strength (TYS) of 299.7 MPa, an ultimate tensile strength (UTS) of 382.6 MPa, and an elongation (EL) of 21.2%. Besides, the underlying strengthening mechanism and ductility enhancement are analyzed and discussed in terms of bimodal-sized grain structure.

Experimental investigation and thermodynamic calculation of the Co–Sn–Bi ternary system

Phase relations of the Co–Sn–Bi ternary system have been studied experimentally for the whole composition range at 250 and 450 °C by means of scanning electron microscopy (SEM) coupled with wave dispersive spectrometer (WDS) and x-ray diffraction (XRD). Five three-phase regions have been confirmed in this system at 250 °C, and three three-phase regions exist in 450 °C. No ternary compound can be observed at these two temperatures. Moreover, Bi has almost no solubility in the binary compounds αCo3Sn2, CoSn, CoSn2 and CoSn3. The primary solidification phases were also distinguished. Based on the experimental results, the thermodynamic calculations for Co–Bi and Co–Sn–Bi system were conducted by using the CALPHAD technique. A set of self-consistent thermodynamic parameters for the Co–Sn–Bi ternary system was obtained, and the experiment results are in good agreement with the calculated results.

Thermomigration behavior of Sn–Bi joints under different substrate

Thermomigration behavior of Sn–Bi joints under different substrate