Sn Wt Research Articles

Influence of Cr inclusion on the microstructural evolutions and tensile properties of Sn-5 wt% Sb solder alloy

Influence of Cr inclusion on the microstructural evolutions and tensile properties of Sn-5 wt% Sb solder alloy

Strong grain size effect on the liquid/solid reactions between molten solder and electroplated Cu

Electrodeposition of Cu metallization and its soldering reaction with solder alloy are of technological significance in microelectronic packaging industry. This study aims to investigate the effect of Cu grain size on the liquid/solid reactions between molten Sn-3 wt% Ag-0.5 wt% Cu (SAC305) solder alloy and electroplated Cu. Two Cu electroplated films, denominated as fine-grained Cu (FG-Cu) and coarse-grained Cu (CG-Cu), are prepared and reacted with SAC305 at 260 °C for 5–20 min. Microstructural characterization shows that the Cu6Sn5 intermetallic compound (IMC) is formed in these two solder joints, while that in the FG-Cu solder joint grows at a faster rate than that in the CG-Cu solder joints. The Cu6Sn5 IMC in the FG-Cu solder joint exhibits a slender column-like grain morphology, unlike the common scallop-like grain morphology in the CG-Cu solder joints. The strong grain size effect is rationalized by comparing the contribution of two fluxes of ripening and interfacial reaction to the growth of Cu6Sn5.

Correlation of microstructure with thermal and tensile creep properties of novel Sn-5Sb-0.5Cu alloy reinforced with Co particles for soldering applications

The present research examined how cobalt microalloying additions of 0.25, 0.5, 0.75, and 1 weight percent affected the microstructural properties, thermal features, and tensile creep characteristics of eutectic Sn-5 wt% Sb- 0.5 wt% Cu (SSC) lead-free solder alloy. According to the results, cobalt additions of 0.25, 0.5, and 0.75 wt% did not affect SbSn phase but significantly refined β-Sn grains, facilitating the formation of fine fibers (Cu,Co)6Sn5 together with plate-like CoSn3 phases, and preventing the formation of Cu6Sn5 phases. Furthermore, a large amount of cobalt (1 wt%) addition accumulated in the coarsening of the CoSn3 phase. Additions of 0.25 wt% Co, 0.75 wt% Co, and 1 wt% Co did not affect the melting temperatures, but pasty ranges had been slightly lowered, which may enhance the thermal characteristics. Addition of 0.5 wt% Co had unfavorable effects on both melting point and pasty range. This has significant effects on solder reliability and electronic service performance. In terms of creep behavior, the SSC-0.75 wt% Co specimens displayed the highest creep resistance because of the fine dispersion of intermetallic compounds (IMCs) and extended the creep-rupture life to a level that is 3.0 times greater than the SSC baseline. Lower creep resistance was observed in SSC-0.25 wt% Co specimens, which was mostly due to the smaller volume fraction of the precipitate phases and the absence of the CoSn3 phase. Depending on the determined stress exponents and activation energies, it is suggested that the dominant deformation mechanism in SSC-xCo solders is the dislocation climb controlled by short-circuit pipe diffusion across the whole temperature range that was examined.

Tin isotopes reveal changing patterns of tin trade, connectivity and consumption from Anatolia and Central Asia at Kültepe

Until recently, what was known about the trade of tin in the ancient Near East was based in large part on information derived from the extensive commercial archives found at the archaeological site of Kültepe (ancient Kaneš) in Turkey dating to the Middle Bronze Age (MBA) c. 1900-1750 BC. These archives were produced by an expatriate community of traders native to the city of Assur in modern-day Iraq and document an extensive shipping of tin ingots from unnamed sources east of their hometown. Tin was carried by donkeys through northern Syria and across the Taurus Mountains to Anatolia where it was sold for silver.This paper presents the first set of tin isotope analyses of bronze objects from Kültepe to test the image provided by these ancient archives, finding that all artifacts dated to the main period of Assyrian trade excavated in the residential areas of the site indeed have high tin content and high values of δ124Sn (0.77–1.74‰) relative to the NIST 3161a standard. Such high values currently compare best with ores from Central Asia. The isotopic analysis of artifacts from the Assyrian Trading Colony Period of Kültepe is therefore consistent with the textual evidence.However, Early Bronze Age samples recovered at the site are instead characterized by lower ranges that extend to neutral δ124Sn values (0.02–1.31‰). Likewise, one artifact coming from Mound Level 7 (c. 1830-1700) at the center of the site where public buildings were concentrated, and one object dated to the Hellenistic Period (Mound Level 2), when the site saw a resurgence in political importance, likewise have lower δ124Sn compositions of 0.11 and 0.31‰, respectively. Both samples also have low to moderate tin content.The Early Bronze Age artifacts form a linear array between artifacts from low δ124Sn-low Sn wt% to high δ124Sn-high Sn wt% that suggests a mixing of two compositional groups – not simply the mixing of two isotopically distinct reservoirs of tin, but also distinct in the amount of tin present in the alloy. This would be consistent with the recycling of low tin bronze objects with local tin, together with high tin bronzes containing tin from Central Asia. The two samples from Mound Levels 7 and 2 suggest that although Central Asian tin was predominant in the MBA, Anatolian tin may have continued to be used in a separate bronze production system that remained active at shifting varying of intensity throughout antiquity.

Effect of interlayer particles on the bonding improvement of aluminum laminated composites

Aluminum-based composites (AMMCs) have become a popular topic in industrial progress. The aluminum (Al) structure is such that, while it is very light, it also has significant strength. This capability has increased the use of Al in various industries, especially the aerospace and marine industries, even more. Other properties of Al include the favorable plasticity of these structures. It is worth mentioning that many methods can be used to produce Al metal matrix composite (AMMC). One of these methods is Accumulated Press Bonding (APB). APB is one of the most powerful processes as a solid welding method for making MMCs. This method can be called a complex technology that has many advantages. One of the main advantages of this method is that it has a high potential to refine the nanostructures that make up a composite, making it possible to design, produce and refine composites consisting of several layers. In addition to advantages, this process also has disadvantages. Actually, in this process, the bond strength (BS) is weak. This study uses Sn particles to improve the BS of Al laminates as filler metal. So, AA1060 bars with different wt% of Sn particles (interlayer filler material) were manufactured at various pressing temperatures (Temp’s) and APB steps. The peeling test was used to evaluate the bonding strength. It was found that the pressing Temp increased APB number of steps and Sn wt%, popular bonds with upper strength were shaped. Also, to illustrate the peeling surface of AA1060/Sn samples, scanning electron microscope (SEM) was used.

Investigation of Microstructure and Mechanical Properties of SAC105 Solders with Sb, In, Ni, and Bi Additions.

Low Ag lead-free Sn-Ag-Cu (SAC) solders have attracted great interest due to their good drop resistance, high welding reliability, and low melting point. However, low Ag may lead to the degradation of the mechanical properties. Micro-alloying is an effective approach to improving the properties of SAC alloys. In this paper, the effects of minor additions of Sb, In, Ni, and Bi on microstructure, thermal and mechanical properties of Sn-1 wt.%Ag-0.5 wt.%Cu (SAC105) were systematically investigated. It is found that the microstructure can be refined with intermetallic compounds (IMCs) distributed more evenly in the Sn matrix with additions of Sb, In, and Ni, which brings a combined strengthening mechanism, i.e., solid solution strengthening and precipitation strengthening, leading to the tensile strength improved of SAC105. When Ni is substituted by Bi, the tensile strength is further enhanced with a considerable tensile ductility higher than 25%, which still meets the practical demands. At the same time, the melting point is reduced, the wettability is improved, and the creep resistance is enhanced. Among all the investigated solders, SAC105-2Sb-4.4In-0.3Bi alloy possesses the optimized properties, i.e., the lowest melting point, the best wettability, and the highest creep resistance at room temperature, implying that element alloying plays a vital role in improving the performance of SAC105 solders.

Modeling and experimental investigation of indentation creep behavior of hypoeutectic Sn-Bi and Sn-Bi- Sb2O3 alloys using genetic programming approach

This study employs genetic programming (GP) to model the impact of aging temperature and the addition of nano-sized Sb2O3 particles on the mechanical properties of hypoeutectic Sn-5 wt% Bi alloy. Vickers hardness measurements were used to investigate the indentation creep behavior of the alloy under different testing conditions, comparing Sn-5 wt% Bi (alloy A) and Sn-5 wt% Bi-0.5 wt% Sb2O3 (alloy B). Microstructure development was studied using a scanning electron microscope (SEM). A MATLAB code was employed to optimize the GP parameters during the training process. Two GP models were developed to describe the indentation creep behavior of alloys A and B, respectively, as a function of dwell time, aging temperature, and applied load, using experimental data with errors of 0.0844 and 0.086 and a correlation coefficient greater than 0.9. The equations generated by the GP approach demonstrate excellent agreement with the experimental findings, and the GP model predicts the data with high accuracy.

Large-strain functional fatigue properties of superelastic metastable β titanium and NiTi alloys: A comparative study

This paper investigates the fatigue behavior of superelastic NiTi and two metastable β titanium alloys - commercial Beta III (Ti-11.5Mo-6Zr-4.5Sn wt%) and Ti2448 (Ti–24Nb–4Zr–8Sn wt%) alloys. In situ cyclic tensile tests performed under synchrotron X-ray radiation were used to precisely characterize the stress induced martensitic (SIM) transformation occurring in these alloys. For the NiTi alloy, an intermediate B2-R SIM transformation was detected before the B2-B19′ SIM transformation and no plastic deformation occurred until failure. All metastable β titanium alloys that were solution-treated before testing underwent a reversible β-α" SIM transformation and plastic deformation prior to failure. Low-cycle strain-controlled fatigue tests were performed in tension-tension strain-controlled mode at 37 °C to evaluate large-strain functional fatigue properties. The fatigue life of metastable β titanium alloys was found to be much better than that of NiTi alloy at large applied strains. After a rapid evolution during the first cycles, the mechanical response was found to be constant for NiTi alloy while it evolved continuously for metastable β titanium alloys. In addition, failure occurred suddenly in NiTi, whereas cyclic softening was observed before failure in metastable β titanium alloys. Fatigue properties at higher applied strains are mainly hindered by SIM transformation and defects generated at austenite/martensite interfaces during cycling. This explains why the studied NiTi alloy showed lower fatigue properties than metastable β titanium alloys. In fact, while SIM transformation is homogeneously nucleated in metastable β titanium alloys, SIM transformation is highly localized in NiTi, resulting in higher concentration of defects that promote crack nucleation and, in turn, degrade the functional fatigue properties.

Applicability Evaluation of Nano-Al2O3 Modified Sn-Ag-Cu Solder in High-Density Electronic Packaging Subjected to Thermal Cycling

Recently, 3D packaging has been regarded as an important technical means to continue Moore’s Law. However, excessive stacking will increase the longitudinal dimension, and one chip with high-density bondings packaging is still needed. Thus, it naturally places higher demand on thermal cycling reliability due to the decreased joint size to satisfy high-density packaging. In this work, the nano-Al2O3 (1 wt.%) modified Sn-1 wt.% Ag-0.5 wt.% Cu low-Ag solder was applied as a solder sample to evaluate the associated thermal cycling reliability. The investigated results revealed that the nano-Al2O3 modified solder did present enhanced thermal cycling reliability, as evidenced by the delayed microstructure coarsening and the inhibited atom inter-diffusion at interface caused by the adsorption of nano-Al2O3 on grain surfaces, and the resultant pinning effect. Worthy of note is that the potential of the newly developed nano-Al2O3 modified solder for high-density packaging applications (e.g., BGA, QFN, and CCGA) was evaluated based on the Finite Element Modeling.

Development and benchmarking of numerical model in OpenFOAM® for the prediction of channel segregation during columnar alloy solidification

• Benchmark sn-5 wt%Pb alloy solidification problem is simulated using OpenFOAM solver. • Mesh sensitivity analysis is performed to resolve the flow in channels segregates. • Effect of microsegregation and mushy zone models on channels formation is studied. • Scheil's model predicts more negative and positive segregation than Lever rule. • Inertial drag in mushy zone significantly affects the channel segregates formation. In the past, most of the numerical studies on the prediction of macrosegregation and mesosegregation (e.g. channel type segregation) were performed using in-house codes and commercial software, both of which have limitations such as huge license costs, non-availability for general public research etc. In this study, a dedicated CFD solver is developed in an open-source platform – OpenFOAM® for the prediction and characterization of channel segregates in castings. The solver accounts for the fluid flow, heat transfer, species transport, multiscale segregation, solidification and mushy zone drag phenomena that occur during alloy solidification. The developed solver is extensively validated with the reported benchmarked experimental and numerical results for the sn-Pb alloy solidification. Direct numerical simulations (DNS) are performed to resolve the flow field in and around the channels (which are of mesoscopic length scale) for the first time. It is observed that mesh size ≤ 2 d 2 (secondary dendritic arm spacing) is required to resolve the flow in channels and accurately predict their morphology and locations. Further, the effect of different microsegregation and mushy zone drag models on the segregation and morphology of channel segregates is thoroughly investigated. The predicted extent of negative and positive segregation is found to be more (negative segregation ∼ 7.7 wt%Pb and positive segregation ∼ 18.7 wt%Pb) in Scheil’s microsegregation model compared to Lever rule. Furthermore, the inertial drag in the mushy zone significantly affects the convective transport of solute and thereby the morphology and the number of channel segregates.

Effect of Bi, Sb, and Ti on Microstructure and Mechanical Properties of SAC105 Alloys.

The Sn-Ag-Cu (SAC) solder alloys with a low Ag (Ag < 3 wt.%) content have attracted great attention owing to their low cost, increased ability in bulk compliance, and plastic energy dissipation. However, some of their mechanical properties are generally lower than the SAC alloys with a higher Ag content. Adding alloying elements is an effective approach for improving the mechanical properties of the SAC alloys. In this study, the effect of Bi, Sb, and Ti on Sn-1 wt.%Ag-0.5 wt.%Cu (SAC105) solder alloys was investigated. The SAC solders with four compositions: SAC105-1 wt.%Bi, SAC105-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb, SAC105-1 wt.%Bi-1 wt.%Sb-0.4 wt.%Ti were prepared. The microstructure and phase compositions were characterized using electron scanning microscopy, and X-ray diffraction. The thermal properties and wettability were also examined. Uniaxial tensile tests and nano-indentation tests were conducted to evaluate the mechanical properties. The results show that adding Bi or Sb could increase the strength of SAC105 alloys mainly due to the solid solution strengthening effect. The creep resistance of SAC105 alloys was also improved with the additions of Bi and Sb. The co-additions of Bi and Sb into SAC105 alloys exhibit an enhanced creep resistance than that calculated by the theoretical calculation. The further addition of Ti into SAC105-1Bi-1Sb alloys demonstrated a much-improved creep resistance, which could be attributed to the synergistic effects of both solid solution strengthening and the precipitation hardening effects.

Study of structural, physical, characteristics and radiation shielding parameters of Bi50-Pb40-Sn10 and Bi40-Pb40-Sn10-Cd10 alloys used for radiation therapy

This work is carried out for the development of radiation shielding block alloys (bismuth based) for radiation therapy. Two different bismuth alloys whose composition, first, Bi-40 wt.% Pb-20 wt.% Sn and secondly, Bi-40 wt.% Pb-10 wt.% Sn-10 wt.% Cd are known as low melting temperature alloys (named fusible alloys). These alloys are used for the protection of vital critical organs inside the radiated area during radiotherapy applications. Structure, mechanical properties, and radiation shielding parameters of prepared alloys by conventional and rapid quench from molten state using the melt-spun technique have been studied and analyzed. It is concluded that from x-ray diffraction analysis, the presence of a new metastable crystalline phase (hexagonal structure a = 3.505, b = 3.505 and c = 5.795 nm) called Pb7Bi3 is detected. The formation of a metastable crystalline phase Pb7Bi3 causes the enhancement of mechanical properties. It is also concluded that the bismuth alloy which is cadmium-free exhibits superior microhardness compared to bismuth alloy containing cadmium. The measurements of radiation parameters were taken using 60Co and 6 MV. X-ray shows that alloy-free Cd has good attenuation coefficient, good mechanical characteristics, Vickers microhardness and moderate melting temperature. We can easily synthesise the bismuth alloy cadmium-free into suitable shapes in addition to it being friendly to the environment (green environment), so that they may be used as a substitute candidate instead of bismuth alloy containing Cd to use in radiation therapy.

Three-Dimensional Numerical Simulation and Experimental Investigations of Benchmark Experiment of Sn-10 wt. %Pb Alloy Solidification Under Thermosolutal Convection

Abstract A full three-dimensional (3D) numerical simulation of solidification was carried out for a benchmark experiment on a binary Sn-10 wt. %Pb alloy. The experiment process involves a melting stage, a first holding stage at constant temperature with electromagnetic stirring, setting a mean horizontal temperature difference (second holding stage), and finally solidification stage by decreasing the temperature under a imposed horizontal temperature gradient. The numerical model is applied only to investigate the solidification stage and compared with the measured temperature fields and macrosegregation obtained from the postmortem analysis. A columnar numerical model based on a two-phase volume-averaged approach is used for the numerical simulation, accounting for thermosolutal convection and assuming perfect microscopic mixing (lever rule) in the mushy zone. It demonstrates that such a model is able to predict stratification in the solute from the liquid phase and mushy zone during the solidification. The effect of the sedimentation on macrosegregations and channel segregation or freckles which develop during the solidification stage is also predicted by the model and compared with experimental data. Emphasis is given to the main factors that have a direct effect on the development and morphology of segregated channels, namely, the remelting phenomenon, dendrite fragmentation, and the solidification front instabilities.

Properties of Sn-3 wt%Ag-5 wt%Cu alloys with Cu6Sn5 intermetallics grain refined by Mg

This paper investigates the influence of Mg additions on the microstructure, thermal properties, electrical properties, and joint strength of bulk and ball grid array (BGA) reflowed Sn-3 wt%Ag-5 wt%Cu solder alloy and the joint intermetallics (IMCs). The cross-sectional microstructure analysis revealed that the addition of Mg effectively triggered the grain refinement of primary Cu6Sn5 IMCs in the bulk solder alloys. In addition, the thickness of the interfacial Cu6Sn5 IMCs layer was suppressed. The optimal addition for refinement is in the vicinity of 0.10 wt%Mg. Furthermore, synchrotron tomography three-dimensional reconstructed imaging reveals that the grain refinement of primary Cu6Sn5 IMCs is also effective even in BGA scale solder joint at normal reflow conditions. These primary Cu6Sn5 IMCs showed a non-faceted morphology. 0.10 wt%Mg addition reduced the number and size of the Cu6Sn5 IMCs. The grain refinement of primary Cu6Sn5 IMCs could be attributed to the presence of Mg, Mg2Sn, and MgO phases that potentially serve as heterogenous nucleation sites. The thermal analysis showed that the degree of undercooling values was significantly reduced to the minimum with 0.10 wt%Mg addition, which increased when the amount of Mg increased to 0.15 wt%. The mechanical properties showed that the ductility of the solder joint at high shear speed was improved.

Numerical modeling and experimental analysis of benchmark experiment of Sn-10 wt%Pb alloy under forced convection by electromagnetic stirring

3D numerical simulation of solidification was carried out for a benchmark experiment on a binary Sn-Pb alloy with rigorous controlled thermal boundary conditions. The experiment consists of solidifying a parallelepiped ingot of Sn-10wt.%Pb composition. The main objective is to give both details of 3D numerical simulation and experimental analysis of the effect of forced convection driven by an alternative traveling magnetic field on the solidification process of Sn-10wt.%Pb alloy. The experiment was carried out under an average experimental temperature difference (DT) equal to 40 K and a cooling rate of (-0.03 K/s). This slow-cooling condition has been used in order to promote segregation formation. A periodically reversed electromagnetic stirring (EM) case with a modulation frequency equal to 0.125 Hz has been investigated in this both numerical and experimental studies. During the solidification process, the time evolution of the temperature field is recorded by more than 68 thermocouples and analyzed. This enables us to determine the temperature evolution over time owing to forced convection. The patterns of the of solute (lead) concentration distribution obtained by numerical results are compared to the experimental X-ray radiographies. A post-mortem analysis is performed allowing us to determine the grain’s form and size in the final macrostructure. Results illustrate clearly that the EM stirring modifies the macrostructure in terms of columnar-equiaxed transition (CET), namely the grain refinement and, on the other hand, it significantly affects the segregation pattern, especially the segregated channel morphology and distribution. Indeed, it shows that this periodicity in the reversal electromagnetic stirring reduces significantly the macrosegregation corresponding to the last liquid solidified, while remaining inactive for reducing the development of segregated channels.

Plasma-assisted CO2 reforming of methane over Ni-based catalysts: Promoting role of Ag and Sn secondary metals

Carbon dioxide (CO2) and methane (CH4) are the primary greenhouse gases (GHGs) that drive global climate change. CO2 reforming of CH4 or dry reforming of CH4 (DRM) is used for the simultaneous conversion of CO2 and CH4 into syngas and higher hydrocarbons. In this study, DRM was investigated using Ag–Ni/Al2O3 packing and Sn–Ni/Al2O3 packing in a parallel plate dielectric barrier discharge (DBD) reactor. The performance of the DBD reactor was significantly enhanced when applying Ag–Ni/Al2O3 and Sn–Ni/Al2O3 due to the relatively high electrical conductivity of Ag and Sn as well as their anti-coke performances. Using Ag–Ni/Al2O3 consisting of 1.5 wt% Ag and 5 wt% Ni/Al2O3 as the catalyst in the DBD reactor, 19% CH4 conversion, 21% CO2 conversion, 60% H2 selectivity, 81% CO selectivity, energy efficiency of 7.9% and 0.74% (by mole) coke formation were achieved. In addition, using Sn–Ni/Al2O3, consisting of 0.5 wt% Sn and 5 wt% Ni/Al2O3, 15% CH4 conversion, 19% CO2 conversion, 64% H2 selectivity, 70% CO selectivity, energy efficiency of 6.0%, and 2.1% (by mole) coke formation were achieved. Sn enhanced the reactant conversions and energy efficiency, and resulted in a reduction in coke formation; these results are comparable to that achieved when using the noble metal Ag. The decrease in the formation of coke could be correlated to the increase in the CO selectivity of the catalyst. Good dispersion of the secondary metals on Ni was found to be an important factor for the observed increases in the catalyst surface area and catalytic activities. Furthermore, the stability of the catalytic reactions was investigated for 1800 min over the 0.5 wt% Ag-5 wt% Ni/Al2O3 and 0.5 wt% Sn-5 wt% Ni/Al2O3 catalysts. The results showed an increase in the reactant conversions with an increase in the reaction time.

Peritectic phase formation kinetics of directionally solidifying Sn-Cu alloys within a broad growth rate regime

Previous studies have shown that the peritectic transformation may not occur and, depending on the cooling rate, the peritectic phase can nucleate and grow directly from the melt. This study investigates the effect of growth rate (pull rate) on a peritectic alloy via in-situ directional solidification, in particular where rapid solidification dramatically alters the microstructure, whereby only the peritectic phase nucleates directly from the liquid. The phase formation events occurring during the directional solidification of a Sn-Cu peritectic alloy were studied, confirming that growth rate has a critical effect on the phase selection of the Sn-10 wt %Cu alloy. Over the range of growth rates studied, competitive nucleation between the pro-peritectic Cu3Sn phase and the peritectic Cu6Sn5 phase occurs, and beyond a critical growth rate, nucleation of the Cu3Sn phase does not occur and the Cu6Sn5 phase nucleates preferentially from the metastable liquid. Phase competition in peritectic alloys is of interest from not only a fundamental perspective but also from a practical viewpoint allowing for unique microstructure design. This work presents for the first time the in-situ directional solidification of a Sn-Cu alloy that involves an equilibrium peritectic reaction and shows the effect of growth rate on phase selection. Furthermore, this study has confirmed that the peritectic transformation does not occur in the investigated Sn-Cu alloy for the range of conditions examined.

A facile fabrication of Sn-doped CeO2 nanocrystalline thin films with enhanced photodiode properties for optoelectronic applications

The advancement of p–n photodiode fabrication employing rare-earth materials has created cogent interest in the field of semiconductor device technology. We report on the formation of pure and Sn-doped CeO2 thin films assembled through spray pyrolysis technique to enhance the p-Si/n-Sn:CeO2 diode performance. A polycrystalline nature of cubical crystal structured Sn-CeO2 thin films was developed on glass slides with various doping levels of tin (0, 2, 4 and 6 wt%). The crystallite size was found to decline with increasing Sn wt%. A uniform surface with tiny spherical-like crystallite grains was observed through the FE-SEM microscope. The existence of Sn ions with the CeO2 system was confirmed by the EDX and XPS spectrum. The effect of Sn doping on the optical absorption and band gap of CeO2 was evaluated, in which the 2 wt% Sn exhibited lower Eg value with maximum absorption. The Sn ions enhanced the electrical conductivity suggesting the semiconducting nature of the films. The p-Si/n-Sn:CeO2 diode was fabricated, and its performance was analyzed under dark and light intensity of 100 mW/cm2. The photosensitivity of the device varied from 17.11 to 671.65%. The ON–OFF photoresponse of 6 wt% Sn is relatively higher than that of pure CeO2.

Effect of Ni, Zn, Au, Sb and In on the Suppression of the Cu3Sn Phase in Sn-10 wt.%Cu Alloys

Since manufacturing is transitioning into Pb-free solder development for electronic assembly and packaging, consumer demands for more compact electronics have increased the importance of reliability issues brought about by the increased density of circuitry. Therefore, the role of alloying elements that can be added to common Pb-free solders such as Sn-Cu or Sn-Ag-Cu alloys in enhancing the properties and performance of the solder becomes important. Microstructural analysis along with direct observation in situ synchrotron radiography were used to study the effect of Ni, Zn, Au, In and Sb on the development of phases in Sn-10 wt.%Cu (Sn-10Cu). It was found that adding Ni and Zn to a Sn-10Cu alloy had the greatest impact on the microstructure with the Cu3Sn phase completely absent after these additions were made. Additions of Au and In also resulted in a reduction in the amount of Cu3Sn; however, the effect was not as pronounced. Removing the Cu3Sn phase from Sn-Cu Pb-free solder alloys is a possible approach for the design of more desirable microstructures that translate to better performance in modern electronic packaging.

Influence of Sb2O3 Nanoparticles Addition on the Thermal, Microstructural and Creep Properties of Hypoeutectic Sn–Bi Solder Alloy

Here we investigate the effects (thermal, microstructural, and creep properties) of adding Sb2O3 nanoparticles to a hypoeutectic Sn-5 wt% Bi solder alloy. The Sb2O3-containing solder alloy was prepared by mechanically incorporating 0.5 wt% Sb2O3 nanoparticles into the Sn-5 wt% Bi solder alloy. The addition of nano-sized Sb2O3 particles to the Sn–Bi solder alloy increases the melting temperature, but only slightly. The main phases of the investigated solder alloys include the β-Sn and Bi-rich phases in addition to the crystalline phase of Sb2O3 nanoparticles. No other intermetallic compounds were observed in the β-Sn matrix. The tensile creep experiments have been carried out in the 303–363 K temperature interval under constant stresses ranging from 5.1 to 7.64 MPa. The creep parameters of both solders increased gradually with increasing creep temperature up to 333 K, after which they increased rapidly with relatively higher values. The creep parameters of the Sb2O3-containing solder alloys are smaller than that of Sb2O3-free solder alloys. The present solder alloys exhibit class-M creep behavior. The calculated stress exponent values and activation energy data for both solders could be related to dislocation climb through core diffusion as the dominant operating mechanism.