Use Of Tin Research Articles

Corrosion behavior of pure tin deposit under 55 °C/85 % RH reliability test

With recent moves to implement lead-free manufacturing in the electronics industry, more attention is being paid to the use of tin. One of greatest limitations regarding the reliability of tin is the undesirable development of tin whiskers. Many factors have been identified as being the cause of these whiskers, though tin corrosion has not. Three types of tin deposit grain structures have been developed in an effort to reduce the growth of whisker formations as type (A) with vertical and regular grain boundary; type (B) with horizontal and irregular grain boundary; and type (C) as a combination of both vertical (the top layer) and horizontal (the bottom layer) grain structures. We kept a series of samples in an oven for 1 year at 55 °C/85 % RH (relative humidity), and then used focused ion beam to examine the corrosion microstructure that occurred three types of deposit structures. We found the preferred path of corrosion to occur along the grain boundary and that tin oxide enlarges the volume of the deposit. In order to release the compressive stress that developed during corrosion, whiskers were formed as the grain structure being vertical. Corrosion developed in different locations of various deposits made of the three grain structures. We studied resulting in whisker growth, cracking and the development of internal oxide.

Use of Tin Based Composite Nanorod Anodes for Rechargeable Lithium Applications

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Cross-Border Impacts of the Restriction of Hazardous Substances: A Perspective Based on Japanese Solders

Despite the relevance of the global economy, Regulatory Impact Assessments of the restriction of hazardous substances (RoHS) in the European Union (EU) are based only on domestic impacts. This paper explores the cross-border environmental impacts of the RoHS by focusing on the shifts to lead-free solders in Japan, which exports many electronics to the EU. The regulatory impacts are quantified by integrating a material flow analysis for metals constituting a solder with a scenario analysis with and without the RoHS. The results indicate that the EU regulation, the RoHS, has triggered shifts in Japan to lead-free solders, not only for electronics subject to this regulation, but for other products as well. We also find that the RoHS leads to a slow reduction in environmental emissions of the target, lead, but results in a rapid increase in the use of tin and silver in lead-free solders. This indicates the importance of assessing potential alternative substances, the use of which may increase as a result of adhering to the RoHS. The latter constitutes a negative impact because of recent concerns regarding resource criticality.

Evaluation of PbSn Alloys Corrosion Inhibition Using Tin and PbO2 Coatings

One of the main failure modes in Lead-Acid Batteries (LAB) is corrosion at the positive plate. This problem has increased significantly the number of warranty claims, becoming a significant loss for this industry. Attempts to prevent corrosion in LABs include the application coatings of metallic oxides in the positive plate. In this work the use of tin and PbO2 as anti-corrosion coatings is explored. The coatings were prepared by electroless deposition and electrodeposition using current pulses. Corrosion rate of grid samples was determined, with and without coating, from Tafel plots. It was found that electrodeposited tin coated grids had the highest corrosion inhibition. On the other hand, electroless tin deposits had the lowest corrosion inhibition activity showing a higher corrosion rate than the uncoated alloy.

Titanium nitride: A new Ohmic contact material for n-type CdS

In devices based on CdS, indium is often used to make Ohmic contacts. Since indium is scarce and expensive, suitable replacement materials need to be found. In this work, we show that sputtered titanium nitride forms an Ohmic contact with n-type CdS. The CdS films, deposited with chemical bath deposition, have a hexagonal crystal structure and are polycrystalline, mostly with a (002) texture. The thickness of the films is ∼600 nm, and the donor density is 1.9 × 1016 cm−3. The donor density increases to 1.5 × 1017 cm−3 upon annealing. The contact resistivity of sputtered TiN on CdS is found to be 4.7 ± 0.6 Ω cm2. This value is sufficiently small to avoid large resistive losses in most CdS device applications. To demonstrate the use of TiN in a CdS device, a Au/CdS/TiN Schottky diode was constructed. The diode has a potential barrier of 0.69 V and an ideality factor of 2.2.

ChemInform Abstract: Asymmetric Aldol Reaction Between Achiral Silyl Enol Ethers and Achiral Aldehydes by Use of a Chiral, Promoter System.

In the presence of a chiral promoter consisting of tin(II) triflate, a chiral diamine, and tributylin fluoride, the silyl enol ether of S-ethyl ethanethioate or S-tert-butyl ethanetioate reacts with aldehydes to afford the corresponding aldol-type adducts in good yields with high enantioselectivities. In the reaction of silyl enol ether of S-ethyl propanethioate with aldehydes, perfect stereochemical control is attained by the combined use of tin(II) triflate, a chiral diamine, and dibutylin diacetate. A wide variety of aldehydes, including aliphatic, α,β-unsaturated, and aromatic aldehydes, are applicable to this reaction. The chiral promoters are characterized by 119 Sn NMR spectra and proved to form the three-component complexes, which behave as chiral Lewis acids. The reaction proceeds directly from silyl enol ethers without any accompanying metal exchange on the enolates

ChemInform Abstract: A New Efficient Chiral Catalyst System. Combined Use of Tin(II) Oxide, Trimethylsilyl Triflate and Chiral Diamine in the Asymmetric Aldol Reaction.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

ChemInform Abstract: Stereoselective Synthesis of Both Diastereomers of the α-Methyl-. beta.-hydroxy-β-alkyl(aryl) Units by Use of Tin(II) Triflate- Mediated Aldol Reaction.

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Gilding on wall paintings from a period

The use of gildings on wall paintings enjoyed its largest development in Italy between the 13th and 14th centuries AD. This work covers a few important artefacts from the Lombard lake region, dating from a period between 1360 and 1520, and painted by the Seregnesi, Da Tradate and De Passeri studios. Its purpose is to understand the gilding techniques by means of scientific examinations (OM, SEM/EDS, FTIR), integrated with information from ancient treatises.Two main gilding techniques have been used in this context: the composite foil (tin and gold), and the single gold foil, in both cases fixed on the wall by a type of oil-based adhesive with the addition of inorganic pigments, mostly lead white and ochres, called missione. The scientific results are in agreement with the recipes contained in the ancient treatises, particularly in the Libro dell’Arte by Cennino Cennini.Extending the research to other case studies in Tessin and Italy, it is clear that the gilding technique was not influenced by the geographical and historical context, but by the final appearance required by the decoration on the wall surface. The use of tin in the composite foil permitted the gold foil to be burnished and engraved.

Effects of Achieving an LDL-Cholesterol Level of <70 mg/dL Compared With the Goal of <100 mg/dL Using Simvastatin or Atorvastatin on Cognitive Processes in High-Risk Diabetic Patients

We aimed to compare the effects of an low-density lipoprotein (LDL)-cholesterol level of 70 mg/dL versus the goal of 100 mg/dL using simvastatin or atorvastatin on cognition. In this open-label trial, patients with diabetes were randomly assigned to simvastatin or atorvastatin 10 mg. If LDL-cholesterol levels, monitored at 30-day intervals, were 100 mg/dL, the doses of simvastatin and atorvasta- tin were increased to a maximum of 40 and 80 mg, respectively. Within each treatment group, patients were stratified by achieved LDL-cholesterol goals into 2 subgroups. Cognitive function was assessed using neuropsychological tests and event-related potential P300 at baseline and after 12 weeks. One hundred fourteen subjects completed the study. The mean LDL- cholesterol levels after simvastatin therapy was 60.2 mg/dL in the subgroup with LDL-cholesterol 70 mg/dL (n 28) and 87.4 mg/dL in the subgroup with levels between 70 and 100 mg/dL (n 29). After atorvastatin, mean LDL-cholesterol was 55.6 mg/dL in the subgroup with LDL-cholesterol 70 mg/dL (n 30) compared with 86.8 mg/dL in the other subgroup (n 27). In the simvastatin subgroup with LDL-cholesterol 70 mg/dL, significant performance decrements on neuropsychological tests of visuospatial percep- tion, orientation, and minor improvement of immediate recall were noted. Executive functions, visuospatial organization worsened also with atorvasta- tin use. Minor improvement in short-term memory occurred in the atorva- statin subgroup with LDL-cholesterol levels of 70 to 100 mg/dL. No correlation existed between the changes in LDL-cholesterol levels and neuropsychological findings in all groups. This study provided partial support for decrements in cognitive function- ing with simvastatin and atorvastatin regardless of achieved LDL-cholesterol goals. The clinical importance, however, is uncertain. However, a mild improvement in short-term memory after the use of both agents could not be excluded.

The Use of Tin(IV) Chloride for Mild and Selective Boc Deprotection on TFA Cleavable Rink-Amide MBHA Resin

An efficient, straightforward and inexpensive method for selective Boc deprotection on Rink-amide MBHA resin using tin(IV) chloride in dichloromethane is presented. Preliminary results suggest that the low degree of cleavage from the resin accompanying the Boc deprotection may depend on steric hindrance associated with the resin. This method can be useful as a selective deprotection step in solid-phase syntheses of cyclic peptides and small molecules in which only a few Boc deprotection steps are required.

Investigation of atomic vapour deposited TiN/HfO 2/SiO 2 gate stacks for MOSFET devices

HfO 2 films were grown by atomic vapour deposition (AVD) on SiO 2/Si (1 0 0) substrates. The positive shift of the flat band voltage of the HfO 2 based metal-oxide-silicon (MOS) devices indicates the presence of negative fixed charges with a density of 5 × 10 12 cm −2. The interface trap charge density of HfO 2/SiO 2 stacks can be reduced to 3 × 10 11 eV −1 cm −2 near mid gap, by forming gas annealing. The extracted work function of 4.7 eV preferred the use of TiN as metal gate for PMOS transistors. TiN/HfO 2/SiO 2 gate stacks were integrated into gate-last-formed MOSFET structures. The extracted maximum effective mobility of HfO 2 based PMOS transistors is 56 cm 2/Vs.

Use of tin as a surfactant material for the growth of thin silver films on silicon oxide

In this letter, we report on the use of tin as an effective surfactant material for silver growing on silicon oxide. We observed that submonolayers of Sn pre-deposited on SiO 2 result in earlier film coalescence and formation of smoother Ag layers. We suggest that Sn atoms reduce the Ag-adatom mobility resulting in experimentally observed increased island density and decreased film roughness. Angle-resolved X-ray photoelectron spectroscopy reveals that Sn remains under the Ag layer giving circumstantial evidence that at later stages of Ag film growth Sn does not influence the interlayer transport.

A Sn-based metal substrate technology for the fabrication of vertical-structured GaN-based light-emitting diodes

Through the use of tin (Sn) based solder balls and patterned laser lift-off technique, a metal substrate technology was proposed for the fabrication of vertical-structured metal substrate GaN-based light-emitting diodes (VM-LEDs). Advantages including reserving the merits of metallic substrate and simplifying the fabrication processes of vertical-structured GaN-based LEDs were demonstrated. As compared to conventional sapphire substrate GaN-based LEDs, the fabricated VM-LEDs with an emission area of 620×620μm2 show an increase in light output power about 145.36% at 350mA with a significant decrease in forward voltage from 4.51to3.46V.

Rational Synthesis of Helically Coiled Carbon Nanowires and Nanotubes through the Use of Tin and Indium Catalysts

The synthesis of helically coiled nanotubes and nanowires through the use of In and Sn catalysts, respectively, in a floating-catalyst-based CVD process, is demonstrated. The figure is a scanning electron microscopy image of helically coiled carbon nanowires prepared from a thermal decomposition of xylene and acetylene in the presence of Fe–Sn catalyst particles. The bright spot at the tip of each nanowire represents the catalyst particle.

Superconducting absorbers for use in ultra-high resolution gamma-ray spectrometers based on low temperature microcalorimeter arrays

Higher resolution gamma-ray detectors are of significant interest to many scientific fields, including fundamental determinations of the Lamb shift in atoms with high atomic numbers, nuclear treaty verification, and environmental monitoring. High-purity germanium is presently the detector material of choice, but germanium detectors suffer from fundamental limitations on their resolution. Recent advances in the use of low temperature calorimeters can provide improvements of more than an order of magnitude. For instance, we report here a resolution of 27 eV FWHM at 103 keV. These calorimeters are made up of two components, a bulk absorber to stop incident gamma-rays and a thermometer made from a thin film electrically biased in the superconducting-to-normal phase transition, called a Transition Edge Sensor, or TES. We have now begun a systematic study of absorber behavior in order to increase efficiency and understand effects on resolution. This study leverages two recently developed capabilities: the ability to microfabricate highly uniform arrays of gamma-ray detectors and the ability to read out signals from many detectors in a single cool-down to 0.1 K using SQUID multiplexer circuits. Here, I will discuss two experiments we are currently conducting to identify better absorber materials. The first involves the use of tin (Sn) as the gamma-ray absorber and the effect of crystal grain size on the thermalization of absorbed photons. The second experiment examines the role of absorbed hydrogen in tantalum (Ta) absorbers. The presence of hydrogen is known to increase the heat capacity of Ta and may be a limiting factor in Ta's use as an improved absorber material.

Microstructure Control and Structure Analysis in the Semi-Solid State of Different Feedstock Materials for the Bearing Steel 100Cr6

The bearing steel 100Cr6 in the forged and hardened condition is of great importance in industrial use. Escaping the geometry restrictions of conventional forging, the application of semi-solid metalworking (SSM) offers significantly increased design freedom. Using conventionally available rolled feedstock material with carbide banding, however, results in a higher segregation tendency during thixoforging, and thus special attention was paid to the feedstock’s “quality”. To achieve a fine-grained, globular microstructure in the semi-solid state, castings with and without the addition of 100 ppm titanium were compared with the hot rolled material. With its inherent nitrogen Ti forms TiN particles, which reduce grain-growth in austenite. The results indicate that TiN precipitates strongly affect grain growth during solid state processing, but the grain size in the semi-solid state can only be influenced for short process times. Generally the cast feedstock materials possess smaller globulites in the semi-solid state compared to forgings, so that a reduction of the sponge effect and a minimization of the segregation in produced components are expected. Since the cast material already showed a fine-grained, globulitic microstructure, the use of TiN is not recommended because of the possible negative influence of TiN on the dynamic mechanical properties.

Recent advances of conductive adhesives as a lead-free alternative in electronic packaging: Materials, processing, reliability and applications

Abstract Tin–lead solder alloys are widely used in the electronic industry. They serve as interconnects that provide the conductive path required to achieve connection from one circuit element to another. There are increasing concerns with the use of tin–lead alloy solders in recognition of hazards of using lead. Lead-free solders and electrically conductive adhesives (ECAs) have been considered as the most promising alternatives of tin-lead solder. ECAs consist of a polymeric resin (such as, an epoxy, a silicone, or a polyimide) that provides physical and mechanical properties such as adhesion, mechanical strength, impact strength, and a metal filler (such as, silver, gold, nickel or copper) that conducts electricity. ECAs offer numerous advantages over conventional solder technology, such as environmental friendliness, mild processing conditions (enabling the use of heat-sensitive and low-cost components and substrates), fewer processing steps (reducing processing cost), low stress on the substrates, and fine pitch interconnect capability (enabling the miniaturization of electronic devices). Therefore, conductive adhesives have been used in liquid crystal display (LCD) and smart card applications as an interconnect material and in flip–chip assembly, chip scale package (CSP) and ball grid array (BGA) applications in replacement of solder. However, no currently commercialized ECAs can replace tin–lead metal solders in all applications due to some challenging issues such as lower electrical conductivity, conductivity fatigue (decreased conductivity at elevated temperature and humidity aging or normal use condition) in reliability testing, limited current-carrying capability, and poor impact strength. Considerable research has been conducted recently to study and optimize the performance of ECAs, such as electrical, mechanical and thermal behaviors improvement as well as reliability enhancement under various conditions. This review article will discuss the materials, applications and recent advances of electrically conductive adhesives as an environmental friendly solder replacement in the electronic packaging industry.

Use of Tin (IV) Porhyrins as Ionophores for the Construction of Phthalate‐Selective Electrodes: Influence of the Structure and Membrane Composition on their Response Properties

AbstractTin(IV) porphyrins derivatives were used as ionophores for phthalate selective electrodes preparation. The influence of ionophore structure and membrane composition (amount of incorporated ionic sites) on the electrode response, selectivity and long‐term stability were studied. Poly(vinyl chloride) polymeric membranes plasticized with o‐NPOE (o‐nitrophenyloctylether) and containing Sn(IV)‐tetraphenylporphyrin (TPP) dichloride (Sn(IV)[TPP]Cl2) or Sn(IV)‐octaethylporphyrin (OEP) dichloride (Sn(IV)[OEP]Cl2), and in some cases incorporating lipophilic cationic (tetraocthylammonium bromide ‐ TOABr) and anionic (sodium tetraphenylborate – NaTPB and potassium tetrakis[3,5‐bis(trifluoromethyl)phenyl]borate‐KTFPB) additives, were prepared and their potentiometric characteristics compared. Both ionophores are shown to operate via a neutral mechanism, and the addition of 10 mol % of lipophilic quaternary ammonium salt derivative to the membrane is required to achieve optimal electrode performance. The potentiometric units prepared, with Sn(IV)[TPP]Cl2 (Type A) or Sn(IV)[OEP]Cl2 (Type B) without additives, presented a slope of −52.8 mV dec−1 and −58.8 mV dec−1 and LLLR of 9.9×10−5 mol L−1 and 9.9×10−6 mol L−1, respectively. The units prepared using the same metalloporphyrins and incorporating 10% mol TOABr presented a slope of −55.0 mV dec−1 and −57.8 mV dec−1 and LLLR of 5.0×10−7 mol L−1 and 3.0×10−7 mol L−1. Their analytical usefulness was assessed by potentiometric determinations of phthalate in water and industrial products providing results that presented recoveries of about 100%.

Interaction of cells with L‐lactide/glycolide copolymers synthesized with the use of tin or zirconium compounds

Comparative studies have been carried out on the viability of cells culture and production of collagen on lactide/glycolide copolymers synthesized using zirconium or tin initiators. Cell response of various cell types: fibroblast-like cells, osteoblast-like cells, monocyte/macrophage-like cells has been examined. Cell response depends on the kind of cells and the initiator used during the synthesis of the polymer. In a number of cases the cells grown on materials containing zirconium have been reported to have better survival (for example, Saos2 cells). An enhanced collagen production on these copolymers has been also observed.