Increasing Sn Content Research Articles

Boosting power output performance of Ba0.85Ca0.15SnxZr0.1-xTi0.9O3 piezoelectric nanogenerators via internal resistance regulation strategy

The piezoelectric charge coefficient (d) and transduction coefficient (d×g) of piezoelectric materials are the key factors that determine the power generation performance of piezoelectric nanogenerators (PENGs). However, it is becoming more difficult to achieve further large improvements in the values of these coefficients. In this work, we propose a new strategy to enhance the output performance of the PENGs by regulating the internal resistance. The internal resistance of Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) PENG was reduced by substituting BaZrO3 with low-resistivity BaSnO3 to obtain high-performance Ba0.85Ca0.15SnxZr0.1-xTi0.9O3 (BCSxZ0.1-xT) PENGs. Although the piezoelectric properties (d and d×g) of BCSxZ0.1-xT deteriorated with increasing Sn content, the power generation capability was markedly improved: the maximum current density (1.27 µA/mm2) and power density (3.09 µW/mm3) were obtained for BCS0.03Z0.07T PENG, reflecting increases of approximately 44% and 18% compared with those values of BCZT PENG, respectively. This work is expected to provide a new way to develop high-performance PENG materials and benefit a wide range of energy harvesting materials.

Theoretical Analysis of GeSn Quantum Dots for Photodetection Applications.

GeSn alloys have recently emerged as complementary metal-oxide-semiconductor (CMOS)-compatible materials for optoelectronic applications. Although various photonic devices based on GeSn thin films have been developed, low-dimensional GeSn quantum structures with improved efficiencies hold great promise for optoelectronic applications. This study theoretically analyses Ge-capped GeSn pyramid quantum dots (QDs) on Ge substrates to explore their potential for such applications. Theoretical models are presented to calculate the effects of the Sn content and the sizes of the GeSn QDs on the strain distributions caused by lattice mismatch, the band structures, transition energies, wavefunctions of confined electrons and holes, and transition probabilities. The bandgap energies of the GeSn QDs decrease with the increasing Sn content, leading to higher band offsets and improved carrier confinement, in addition to electron-hole wavefunction overlap. The GeSn QDs on the Ge substrate provide crucial type-I alignment, but with a limited band offset, thereby decreasing carrier confinement. However, the GeSn QDs on the Ge substrate show a direct bandgap at higher Sn compositions and exhibit a ground-state transition energy of ~0.8 eV, rendering this system suitable for applications in the telecommunication window (1550 nm). These results provide important insights into the practical feasibility of GeSn QD systems for optoelectronic applications.

Effect of Thickness on Structural, Morphological, and Optical Properties for Nanocrystalline Thin Films of Cd1-xSnxS, for Optoelectronic Applications

Thin films of Sn1-xCdxS nanocrystals (X=0,0.7, and 1) with different thicknesses 200, 300, and 400 nm were prepared on glass bases at 300 C by the participation method and chemical spray pyrolysis method (CSP). The effect of the concentration of Sn and thickness on the structural and optical properties of the prepared films was studied. The films were characterized to evaluate the structure, transmittance, and optical energy band gap. X-ray diffraction (XRD) studies showed that the films were polycrystalline with hexagonal and orthogonal structures. XRD and atomic force measurement results showed that the grain size increases with its thickness. The optical band gap energies and optical transmission and absorption types of the membranes were determined from the optical transmittance spectra. Optical absorption studies in the wavelength range 200-1100 nm showed that the energy gap values of the films decrease from 2.48-1.95 eV, 2.41-1.92 eV, and 2.3- 1,89 eV with increasing Sn concentration and with increase the thickness 200, 300, and 400 nm respectively. The best properties of the prepared material were determined for its possible use in the manufacture of solar cells.

Investigation of sensing properties of Sn-doped NiO thin films for the detection of ammonia gas

In this study, we detail the fabrication of Sn-doped nickel oxide thin films using the spin-coating technique, elucidating the impact of Sn doping on structural, optical, and gas sensing properties. Systematic analysis via XRD, SEM, AFM, and UV–Visible spectroscopy delves into the structural and optical characteristics of the films. Notably, gas sensing capabilities, specifically towards NH3, are investigated. XRD analysis reveals the polycrystalline nature of NiO thin films, with crystallinity diminishing as Sn concentration increases. SEM and AFM analyses highlight a uniform film surface with spherical-shaped particles, and increased surface roughness with higher Sn content, a crucial factor for gas sensing applications. Raman analysis showcases first-order phonon modes of vibrations of Ni-O, while optical studies affirm the films' transparency in the visible wavelength. Notably, in ammonia gas sensing tests at room temperature, the 8 mol% Sn-doped NiO thin film exhibits an exceptional response of 3200 %, with a rapid 40-second response time and a 25-second recovery time at a 150 ppm concentration of ammonia gas. These findings suggest that Sn-doped NiO thin films hold promise as effective gas sensors for NH3 detection.

Thermochromic response of an individual Sn:VO2 strip with multiple coexisting phase domains

ABSTRACT The respective roles of Sn atoms and oxygen vacancies (Ovs) on phase transition in an isolated Sn:VO2 with multi-domains were investigated through the Temperature-dependent Raman spectra and the dynamical sequence of phase transformation. A Component-Temperature phase diagram depicting the dependence of phase transformation temperature on the content of Sn or Ovs is constructed. The increasing Sn content could elevate the tensile stress to sequentially induce the metallic R phase to finally form semi-conductive M1, T1, T2, and M2 phases. Meanwhile, the presence of oxygen vacancies caused by doped Sn exerted pressure stress to perturb the M2 phase to narrow its existing region slightly. In a certain order, the four co-existing phases M1, T1, T2, and M2 in an individual Sn:VO2 could be successively obtained by the distinct Semiconductor-Semiconductor Transition from M2, after undergoing Metal–Semiconductor Transition of R-M2 at 52°C, 62°C, 65°C, 67°C, respectively.

Preparation and measurement of a sandwiched Sn atomic beam source for laser resonance ionization mass spectrometry.

Isotope analysis of Sn plays a crucial role in geochemical studies and in monitoring nuclear contamination. Nevertheless, prevalent analytical techniques for examining Sn isotopes encounter the issue of isobaric interference, markedly impacting the accuracy of the test results. Laser resonance ionization mass spectrometry (LRIMS) can effectively overcome the difficulties associated with the isobaric interference inherent in commercial mass spectrometry. In this paper, different amounts of Sn were prepared on Re filaments by electrodeposition and tested via LRIMS. The results showed that the average detection efficiency of LRIMS decreased with increasing total Sn content from 1 μg to 4 μg, and the fluctuations in the test results among the samples increased significantly. Therefore, the electrodeposition process, as well as the composition and morphology of the deposits were characterized by SEM, EDS and XPS; results showed that the degradation of the samples with increasing Sn content was attributed to the complexity of the composition, micro-structure, valence of the deposits, and the interference of various elements. To cope with the anomalies encountered above, the deposits were heat-treated at 600 °C in a hydrogen atmosphere to eliminate detrimental impurities, like Cl, and Sn was effectively reduced to an almost singular atomic state. Furthermore, a titanium layer was covered on the surface of the heat-treated deposit by magnetron sputtering. Ultimately, a highly efficient and stable Sn atomic beam source with a sandwiched structure has been successfully developed and exhibits broad application prospect.

Dual effect to improve the electrical properties of SZO films grown by nitrogen pneumatic spray pyrolysis.

The principal aim of this study is to reduce considerably, via Sn doping, the resistivity of ZnO thin films prepared by simple, flexible, and cost-effective nitrogen pneumatic spray pyrolysis (NPSP) method on glass substrates at a temperature of 400°C. Different Sn content was tested (Sn/Zn = 0, 1, 3, 5 wt%) in an attempt to reduce the concentration of excessive oxygen atoms and create more free electrons. The microstructural, optical, morphological, and electrical properties of the films have been studied. The x-ray diffraction analysis demonstrated that tin-doped SZO films exhibited polycrystalline nature with a preferential orientation along (002) plane with the appearance of a new orientation (101) with the increase of Sn concentration leading then to bidirectional growth. The deposited SZO films showed an average optical transmittance of about 80% in the UV-visible region (200-800 nm) with optical band gap values at around 3.27 eV. Photoluminescence emissions of SZO samples presented three main peaks: near band edge emission, violet emission, and the blue-green emission. The surface morphology of the films obtained by scanning electron microscope (SEM) exhibited the change in morphology with increasing the Sn content. A minimum electrical resistivity value of about 17·10-3 Ω·cm was obtained for 3% SZO films. SZO films prepared by the NPSP method can be used as transparent window layer and electrodes in solar cells. RESEARCH HIGHLIGHTS: Highly oriented, conducting, and transparent Sn-doped ZnO films are successfully synthesized. The film growth orientation changed from mono-directional (002) axis to bi-directional (002) and (101) axis according to Sn doping. Ultraviolet and green emissions are noted by photoluminescence investigation. A minimum resistivity is observed for 3 wt% SZO film. The dual positive effect of the carrier gas used (N2) and Sn doping is confirmed.

Chemically prepared p-type Sn doped ZnO nanoparticles: Synthesis, characterization and its antibacterial properties

The undoped and transition metal doped ZnO nanoparticles are prepared by the chemical precipitation method. Transition metal Sn is chosen as the dopant. The doping concentration of Sn is varied from 0 % to 15 % and the effects of the doping concentration of Sn on structural, optical and antibacterial properties are discussed. The increasing Sn doping concentration increases crystallite size and reduces the strain of the nanoparticles. The band gap is red-shifted due to the addition of Sn. Irrespective of the doping concentration, the hole concentration is larger than the electron concentration. The observed Hall coefficient is in the order of 10−8 m3 C−1, and it decreases non-linearity as the Sn concentration increases. The refractive index also depends on the doping concentration. The doping of Sn enhanced the zone of inhibition against E. coli, S. aureus, and P. aeruginosa. It has been observed that the ZnO nanoparticles doped with Sn have impressive antibacterial activity against both Gram-positive and Gram-negative bacteria.

Revealing Low Thermal Conductivity of Germanium Tin Semiconductor at Room Temperature

AbstractThe low thermal conductivity of a material is a key essential parameter for its potential application in high‐performance thermoelectric devices. Unprecedently low thermal conductivity of germanium tin (Ge1−xSnx) semiconductor thin film is experimentally obtained at room temperature. The thermal conductivity decreases with increasing Sn concentration in the relaxed Ge1−xSnx binary alloy, which is explained mainly by increasing the interatomic distance between atoms via alloying. A pronounced decrease of thermal conductivity, by over 20 times, from 58 W m−1K−1 in Ge to ≈2.5 W m−1K−1 in relaxed Ge1−xSnx, with Sn content up to 9% is observed. This thermal conductivity is just ≈2 times higher than that of the state‐of‐the‐art thermoelectric material, Bismuth Selenium Telluride. Ge1−xSnx, in contrast, is a non‐toxic Group‐IV semiconductor material, that is epitaxially grown on a standard silicon wafer up to 300 mm diameter using the semiconductor industry standard epitaxial growth technique. As a result, it can lead to the creation of a long‐awaited high‐performance low‐cost thermoelectric energy generator for room‐temperature applications in human's daily life and would make a substantial contribution toward global efforts in CO2 emission‐free and green electricity generation.

Effect of Sn Addition on the Microstructure and Age-Hardening Response of a Zn-4Cu Alloy

The aim of this research is to assess the influence of Sn inclusion on the microstructure evolution and age-hardening response of a Zn-4Cu alloy. This is the first study to correlate the age-hardening response to the microstructure of Zn-4Cu alloy reinforced with different Sn contents. A series of Zn-4Cu-Sn alloys were successfully fabricated with different Sn concentrations in the range of 0.0–4.0 wt.% using permanent mold casting. The microstructure of Zn-4Cu-Sn alloys was investigated by means of a scanning electron microscope (SEM) attached with an energy dispersive spectroscope (EDS) and X-ray diffraction (XRD) line profile analysis. At room temperature, the Vickers microhardness measurements were used to assess the age-hardening response of alloys. The results show that the microhardness of the Zn-4Cu (ZC) binary alloy increases a little bit from 76 to 80 HV as the aging time increases from 2 to 128 h, respectively. For aging times up to 16 h, the microhardness of all Sn-containing alloys decreases but then increases again. The lowest hardness belongs to the ZC-1.5Sn alloy, and the Sn-Zn-3.0Sn alloy has the highest; the other alloys fall somewhere in between. At high aging times (64 and 128 h), the microhardness of all Sn-containing samples increased continuously with an increasing Sn content from 0.0 to 3.0 wt.%. When the Sn-containing alloys (3.5 and 4.0 wt.% Sn) were aged for 64 and 128 h, the hardness declined by 7.94% and 8.90% compared to their peak aging hardness values, respectively. By considering the structural changes that occur in the Zn-4Cu-Sn alloys, the reasons for the observed variations in microhardness data with increasing Sn content and aging time were elucidated. X-ray diffraction (XRD) data was analyzed to determine the zinc matrix’s lattice parameters, c/a ratio, and unit cell volume variations.

Production and Characterization of Ta-Sn Alloy Foam for Biomedical Applications

In this study, Ta-Sn alloy foam was manufactured by using space holder method for biomedical applications. The aim of the study is development of an alloy with suitable mechanical properties, with good medical imaging (digital radiography, computed tomography) properties (radiopacity), with high bioactivity. Powder metallurgy-based space holder method enables manufacturing of open-cell foam with low elastic modulus. Powder mixtures were prepared by mechanical alloying. Carbamide was used as a pore former. Ta has suitable radiopacity, strength, ductility, corrosion resistance and biocompatibility. But Ta has high price, high melting temperature, high activity, and high density. Sn addition was lowered the melting temperature, and cost of Ta. Sinterability of Ta, which is a refractory metal, was enhanced by Sn addition. Corrosion behaviour of Ta alloy was examined. Young’s modulus was determined by compression and ultrasonic tests. Increasing Sn content of the alloy increased the Young’s modulus. Increasing porosity decreased the Young’s modulus. Ta alloy has no cytotoxic potential according to neutral red test. Sn addition was lowered the polarization resistance and slightly increased the corrosion rate of Ta-Sn alloy samples.

Microstructure and Superelasticity of Cu–Sn Shape-Memory Microwires by Glass-Coated Melt Spinning

Cu–Sn shape-memory microw ires were fabricated by a glass-coated melt spinning method. Effects of Sn content on the microstructure and mechanical properties of microwires were investigated. The phase transforms from martensite to austenite with an increase in Sn from 14.0 atomic percent (at.%) to 16.5 at.%. When the Sn content exceeds 16.5 at.%, a highly ordered intermetallic phase, δ, formed. The fracture stress (σf) and the critical stress for martensitic transformation (σMs) increases with an increase in Sn content. The mechanical properties as well as the superelasticity were greatly improved by a high cooling rate in the glass-coated melt spinning method. A bamboo-grained structure was formed in the Cu–Sn microwire with a Sn content of 16 at.% by annealing at 750 °C for 5 h before quenching in water. The results indicate that two opposite strategies of refining the grain size to the micrometer level, or increasing the grain size to a one dimensional size of specimen, e.g., the diameter of the wire, are both effective in improving the superelasticity of the Cu–Sn alloy.

Mechanical and tribological characteristics of hypo eutectic Al-7Si alloy-based composite reinforced with Sn metal powder and Al2O3 using bottom pouring stir casting technique

The present work highlights the significant effects of varying wt% of Sn metal powder in the hypo eutectic Al-7Si/10 wt% Al2O3 composite. The composites were manufactured through a multi-stage stir casting route and characterized for mechanical and wear behavior using ASTM standards. The results revealed that the increase in Sn content up to 4 wt% in the matrix enhanced the microhardness, tensile properties, and reduced the porosity. The Al-7Si/10 wt% Al2O3 composite with 4% Sn particle reinforcement shows the highest tensile strength and hardness of 132 MPa and 90 BHN, respectively. All composites exhibited a ductile mode of failure, as evidenced by the tear ridges and dimples on the tensile fracture surface. By adding of Sn metal powder to the material system, the wear rate and coefficient of friction were reduced. At 1000 m of sliding distance and 1 ms−1 of sliding velocity, the wear loss of 8 wt% Sn composite was decreased by 88.8% as compared to Al-7Si base alloy at a normal load of 10 N whereas, at 40 N of normal load, the wear loss was decreased by 66.6%. During the wear process, the Sn metal powder surfaced and formed a thin tribo film that mechanically mixed with the surface, resulting in reduced friction. The layer at the interface prevented direct contact between asperities on the mating surface, which reduced wear loss. The composites without Sn metal powder exhibited adhesive wear and delamination as the primary wear mechanisms, while composites with Sn showed predominantly adhesive wear. Regression analysis followed by a desirability function approach was carried out to develop the model and optimize the operating conditions of the experiments.

Effect of Sn on corrosion resistance of Ti-Cu-Ni amorphous coating

Ti50Cu35-XNi15SnX (X = 5,6,7, wt%) Ti-based amorphous composite coatings were prepared on TA1 by atmospheric plasma spraying. The phase and microstructure were analysed by X-ray diffractometerand scanning electron microscope. The obtained cross-section image of the titanium-based amorphous composite coating confirmed the successful preparation of the amorphous coating. The phase analysis results indicated that an increase in Sn content resulted in a decrease in the amorphous content of the coating. The electrochemical results revealed a significant improvement in the corrosion resistance of the coating compared to the TA1 substrate, consequently enhancing the service life of the electronic material. When the Sn content was 5 wt%, the minimum current density of the coating reached 8.62 × 10-6 A/cm2, and the corrosion rate was 16 times lower than that of the TA1 substrate. As the Sn content increased, the current density of the coating increased from 8.62 × 10-6 A/cm2 to 5.08 × 10-5 A/cm2. Overall, the corrosion resistance of the coating exhibited a downward trend. This observation could be attributed to the decrease in amorphous content caused by the higher Sn content, resulting in a reduction in the corrosion resistance of the coating.

Joining mechanism, microstructure, and mechanical properties of AZ31/6061 joint prepared by pouring fusion welding process assisted with Zn-xSn brazing filler

In this study, AZ31/6061 dissimilar metal joints were manufactured using pouring fusion welding assisted with Zn-xSn brazing filler, and the process, microstructure and mechanical properties of Mg/Al joint were investigated. During welding, the addition of molten Zn-xSn brazing filler completely isolates the direct contact of Mg/Al, preventing the formation of Mg-Al intermetallic compounds. As the Sn content changes, the microstructure of the joints also changes. When the Sn content is 25 wt.%, the microstructure of the AZ31 side is dominated by Mg-Al-Zn ternary eutectic structure, Al6Mg11Zn11, (β-Zn + MgZn2), Al-Zn-Sn (SS), Sn (SS) and Mg2Sn. And the microstructure of the 6061 side is dominated by Al-Zn-Sn (SS), β-Zn, Al-Zn-Sn (SS), and Sn (SS). The width of the Mg-Al-Zn ternary eutectic structure layer decreases with the increase of Sn content. In addition, high Sn content and high heat input promote the formation of Mg2Sn, and large amounts of Mg2Sn are generated with Zn-40Sn interlayer. The average microhardness of the joint gradually decreases with the increase of Sn content. However, the shear strength of the joint first increases and then decreases, and the shear strength of the joint with the Zn-25Sn interlayer is the highest, which is 50.60 MPa. Fracture mode is cleavage fracture.

Mesoporous SnO2–MoO3 catalyst for diesel oxidative desulfurization: Impact of the SnO2/MoO3 ratio on catalytic efficiency

Vehicular SOx emissions have a huge detrimental impact on public health, catalytic converters, and the environment. Developing strategies to remove sulfur from diesel and thus safeguard the above is imperative. A series of SnO2–MoO3 mixed oxides and mono oxides MoO3 and SnO2 were prepared by soft template method, calcined at 450 °C and successfully tested in model diesel oxidative desulfurisation (ODS). The impact of the SnO2/MoO3 mole ratio (hereinafter denoted as Sn/Mo) on catalytic efficiency was investigated, among other catalytic parameters. The obtained samples were analyzed using X-ray diffraction (XRD), Raman spectrocscopy, scanning electron microscopy (SEM), N2-physisorption and titration method for acidic properties. The study demonstrates that mixing SnO2 and MoO3 improves acidic sites, crystallinity, and morphological properties of pure SnO2. The addition of MoO3 increased oxygen vacancies and the surface area of SnO2. High acidic site densities of 49.3, 47.4, and 46.7 mEqg−1 were observed for the catalysts with 2:1, 1:1, and 1:2 Sn/Mo mole ratio, respectively. The catalytic efficiency increased with an increase in Sn content with the highest catalytic efficiency of 99.8% for the dibenzothiophene (DBT) oxidation achieved in 30 min for Sn/Mo (2:1) catalyst compared to 92 and 70% for Sn/Mo 1:1 and 1:2 catalysts, respectively. The rate constant for the reaction was 0.057 min−1, which is eight times that of MoO3; 0.007 min−1 and three times that of SnO2; 0.017 min−1. The ODS mechanism utilizing the SnO2–MoO3 catalyst was proposed. The prepared SnO2–MoO3 catalyst demonstrated a high potential for industrial desulfurisation applications.

Strain-driven anomalous elastic properties of GeSn thin films

Elastic strain engineering in the GeSn bandgap structure is an attractive area for designing novel material properties. The linear interpolation of the elastic constants of Ge and Sn is commonly used to estimate their respective values for Ge1−xSnx alloys. This work reveals that Young's modulus of Ge1−xSnx epitaxial layers has a non-monotonic dependence on Sn composition. It is shown that the decrease in the elastic modulus correlates with the increase in Sn content in pseudomorphically grown Ge1−xSnx-epilayers with Sn concentration in the range of 1–5 at. % and subcritical thicknesses. An anomalous increase in the elastic modulus is observed with the further increase in Sn content (12 at. %), which is also accompanied by an increase in in-plane tensile strain. Phase separation and a decrease in the elastic modulus are observed for Ge1−xSnx-epilayers grown above the critical thickness with Sn concentration ≥ 12 at. %. A correlation between the experimental elastic moduli and calculated elastic energies explains the complexity of strain-driven anomalous elastic properties of Ge1−xSnx-epilayers. The observed anomalous behavior of the Young's modulus for these GeSn epitaxial layers appears to be related to their recently predicted and observed short-range atomic order.

The effect of the concentration of tin (Sn) in the metallic precursor, on the structure, morphology, optical and electrical properties of electrochemically deposited lead-tin-sulphide (PbSnS) thin films

A study has been carried out to investigate the effect of the concentration of Sn in the metallic precursor on the structure, morphology, optical and electrical properties of PbSnS thin films. The films were directly electrodeposited on ITO-coated glass substrates using a 3-electrode electrochemical cell having graphite as the counter electrode and Ag/AgCl as the reference electrode. Several depositions were carried out, with each deposited film having a different concentration of Sn in the metallic precursor whilst all other parameters were kept constant for all the films. Post deposition annealing was carried out in air at 250 o C for an hour. A variety of techniques were used to characterize the films. Results showed that the increase in Sn concentration did not modify the structure and preferred orientation of the films. However, it caused a slight increase in the average grain size of the films and electrical conductivity. All the films showed direct transition with the optical band gap reducing with increasing Sn concentration. The refractive index of the films showed anomalous dispersion behaviour within the UV region, and normal dispersion in the visible and infrared regions, whilst following an increasing trend with the grain size. SEM image showed spherically shaped grains of different sizes distributed randomly with good coverage across the entire area of the substrate. The EDAX spectrum was consistent with formation of the ternary PbSnS compound on ITO-coated glass substrate. Overall results indicate that, the optical and electrical properties of the electrochemically deposited PbSnS thin films can be tuned to make them suitable for specific applications by varying the concentration of Sn in the metallic precursor.

Corrosion Passivation in Simulated Body Fluid of Ti-Zr-Ta-xSn Alloys as Biomedical Materials.

The powder metallurgy method was used to manufacture three Ti-based alloys: Ti-15%Zr-2%Ta-4%Sn (Ti-Zr-Ta-4Sn), Ti-15%Zr-2%Ta-6%Sn (Ti-Zr-Ta-6Sn), and Ti-15%Zr-2%Ta-8%Sn (Ti-Zr-Ta-8Sn). Electrochemical measurements and surface analyses were used to determine the effect of Sn concentration on the corrosion of these alloys after exposure to a simulated body fluid (SBF) solution for 1 h and 72 h. It was found that the passivation of the alloy surface significantly increased when the Sn content increased from 4% to 6% and then to 8%, which led to a significant reduction in corrosion. The impedance spectra derived from the Nyquist graphs also explained how the addition of Sn significantly improved the alloys' polarization resistances. According to the change in the chronoamperometric current at an applied anodic potential over time, the increase in Sn content within the alloy significantly reduced the currents over time, indicating that the uniform and pitting corrosion were greatly decreased. The formation of an oxide layer (TiO2), which was demonstrated by the surface morphology of the alloys after exposure to SBF solution for 72 h and corrosion at 400 mV (Ag/AgCl) for 60 min, was supported by the profile analysis obtained by an X-ray spectroscopy analyzer. It was clear from all of the findings that the tested alloys have a remarkable improvement in resistance to corrosivity when the Sn content was increased to 8%.

Composition and strain dependence of intrinsic and substitutional defect formation energies in Sn[formula omitted]Ge[formula omitted] alloys

We present a density functional theory investigation of the formation energies of intrinsic and substitutional defects in SnxGe1−x alloy as a function of both Sn composition and biaxial strain relevant to heteroepitaxial interface settings. Special quasi-random supercell structures (SQS) are used obtain the ground state energy of the initial and defect bearing SnxGe1−x alloys. Intrinsic defects considered in this study include the vacancy and [110] split Ge interstitial, while substitutional defects include the analogous [110] split Sn interstitial, as well as substitutional Sn and P. The study focuses on SnxGe1−x alloy compositions with 0%–25% Sn content and compressive and tensile strains up to 2%. The results reveal a complex coupling of strain and compositional dependence of formation energies among different types of defects. The formation energies of split [110] Ge interstitial and substitutional Sn defects decrease monotonically with increasing Sn content while the intrinsic vacancy, Sn split [110] interstitial, and substitutional P defects exhibit a minimum formation energy between 13%–19% Sn. Biaxial strain increases the formation energy of all defects by approximately 0.1 eV for an absolute strain of 1%.