Tin Powder Research Articles

Industrially fabricated in-situ Al-AlN metal matrix composites (part A): Processing, thermal stability, and microstructure

This study introduces in-situ aluminum (Al)-aluminum nitride (AlN) metal matrix composites (MMCs) manufactured by a powder metallurgy (PM) cost-effective approach realized at a large industrial scale. The Al-AlN MMCs were targeted for structural load-bearing applications with an expected service at elevated temperatures not normally associated with a use of conventional Al-based alloys and MMCs. Commercial Al, magnesium, and tin powders were processed by readily available PM techniques of blending, cold isostatic pressing (CIP), a solid-state nitridation in a static gaseous nitrogen, and a hot direct extrusion. Two sound voids free Al + 8.8 and 14.7 vol% AlN MMCs were reproducibly fabricated in a form of the long extruded bars with the cross-section of 80 × 15 mm. The microstructure of nitrided and extruded MMCs was presented in details. A typical yolk-shell-like microstructure of Al metallic core and nitrided layer was formed homogenously in a volume of the CIP bulky (~25 kg) billets upon nitridation. The microstructure of extruded Al-AlN MMCs consisted of Al grains elongated into the extrusion direction. The Al grain structure was embedded with the evenly distributed micrometric regions formed by a high density AlN nanocrystals in Al matrix. A stability of the tensile mechanical properties of as-extruded Al-AlN MMCs was pursued in transversal and longitudinal directions after the annealings performed at 300–600 °C for 24 h. Owing to an effective stabilization by the stable and fine AlN dispersoids by Zener pinning action no major changes to the mechanical properties took place after annealing up to 500 °C.

Gas tungsten arc cladding on AZ31B magnesium alloy substrate with Al, Co and TiN mixed precursor powders

This present research paper discusses about the fabrication of metal matrix composite coating on AZ31B magnesium alloy substrate with Al, Co and TiN mixed precursor powders by gas tungsten arc (GTA) cladding process. Firstly, Co and TiN powders were mixed properly in the ratio of 1:1. Thereafter, three samples with different compositions of 20 wt% (Co + TiN)), 25 wt% (Co + TiN)), 30 wt% (Co + TiN)) and balance aluminium powder were developed by preplaced technique. The samples were heated by TIG torch at the optimized parameter as current of 110 Amp, voltage of 25 V, welding speed of 4.23 mm/s and thermal energy of 3.12 kJ/cm. After melting and solidification metallurgical bonding between coating and substrate occurs. The microstructure and chemical composition of the coated samples were analysed by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) respectively. The micro hardness of coated samples were analysed by Vickers micro hardness testing. It was found that with increase in percentage content of Co + TiN the amount of microhardness increases. Furthermore, it was found that the value of maximum microhardness was 422 HV0.1, which was nearly seven times higher than that of the magnesium alloy substrate (64 HV0.1).

Effect of tungsten nanoparticles on interaction of Sn-Cu-Co metallic matrices with diamond

The effect of tungsten nanoparticles on interaction of sintered Sn-Cu-Co metallic matrices with diamond has been studied. Nanoparticles were obtained by grinding standard tungsten powder in a planetary-centrifugal mill. Commercially pure tin, copper, and cobalt powders were mixed with synthetic diamonds and the milled tungsten. Samples were shaped by static pressing in a mold and sintered in vacuum at 820°C. The sintered samples were subjected to static compression test, and hardness of the metallic matrices was measured. The structure of fractures and distribution of the elements over them were explored by the SEM and energy dispersive X-ray microanalysis methods. It has been determined that introducing tungsten nanoparticles into the composite material contributes to dispersion hardening of the metallic matrix and higher strength of its adhesion to diamond.

Karakterisasi Serbuk Timah dari Sistem Atomisasi Gas Argon Panas - Sub Sistem Gas Alir Tabung Gas

<p class="Abstract">The tin powder was used in some applications and technology such as for part manufacture through alloying, pressing, and sintering process, mixing material for the pyrotechnic application, the main material for solder pasta, mixing material on tin chemical, and others. Therefore, the demand for tin powder with a small size, spherical shape, and high purity is increasing severely. Indonesia (PT. Timah Tbk.) is one of the world’s largest producers of tin raw materials. This raw material can be processed be as powder by the atomization method. In this research, hot argon gas atomization system was used to generated tin powder. Raw tin was melted in a melting chamber with temperature variations of 600, 700, 800, and 900 °C. This experiment generates powder with a dominant size of 37 – 150 mm. Meanwhile, for size powder of 0 – 30 mm, dominated by size range of 0 – 10 mm. Furthermore, the size powder of 0 – 30 mm is composed of tin phase, without tin oxide. The tin powder of melting chamber temperature of 900 °C produces the largest tin powder with a size of 0 – 10 mm and spherical powder.</p>

Development of core–shell-structured Ti-(N) powders for additive manufacturing and comparison of tensile properties of the additively manufactured and spark-plasma-sintered Ti-N alloys

In this study, Ti-(N) powders with a core–shell structure were prepared via a nitriding process of titanium (Ti) powders for metal additive manufacturing (AM). Nitriding of spherical Ti powders (D50=130 µm and D50=63 µm) was carried out at different temperatures from 873 K to 1373 K for 10 min. The nitriding process enabled the manufacture of a core–shell-structured Ti-(N) powder, where an N-enriched shell surrounds a lower N core. The thickness of the N-rich Ti shell increases exponentially with increasing nitriding temperature. Depending on nitriding temperature, a shell layer consisting of Ti2N and TiN compounds can form. Based on X-ray diffraction (XRD) results, it was identified that the N-rich shell is composed of (i) only Ti(N) solid solution when nitrided below 1023 K; and (ii) Ti(N) solid solution, Ti2N and TiN compounds if nitrided at or above 1023 K. The core–shell-structured Ti-(N) powders were subsequently used to manufacture bulk samples by spark plasma sintering (SPS) and laser metal deposition (LMD) processes for comparison. The microstructure was characterized and discussed. LMD-fabricated Ti-N alloy samples exhibited high tensile strength (965 MPa) with good tensile ductility (7.6%) due to the homogeneous distribution of N and fine grain size. In contrast, SPS-fabricated Ti-N alloy samples using the same nitrided Ti-N powder showed much lower tensile strength (708 MPa) with essentially no tensile ductility (0.3%) due to the inhomogeneous distribution of N. LMD can allow the fabrication of strong and ductile Ti-N alloys while it is not possible by SPS.

Microstructure and Mechanical Properties of NiTi-Based Eutectic Shape Memory Alloy Produced via Selective Laser Melting In-Situ Alloying by Nb.

This paper presents the results of selective laser melting (SLM) process of a nitinol-based NiTiNb shape memory alloy. The eutectic alloy Ni45Ti45Nb10 with a shape memory effect was obtained by SLM in-situ alloying using a powder mixture of NiTi and Nb powder particles. Samples with a high relative density (>99%) were obtained using optimized process parameters. Microstructure, phase composition, tensile properties, as well as martensitic phase transformations temperatures of the produced alloy were investigated in as-fabricated and heat-treated conditions. The NiTiNb alloy fabricated using the SLM in-situ alloying featured the microstructure consisting of the NiTi matrix, fine NiTi+β-Nb eutectics, as well as residual unmelted Nb particles. The mechanical tests showed that the obtained alloy has a yield strength up to 436 MPa and the tensile strength up to 706 MPa. At the same time, in-situ alloying with Nb allowed increasing the hysteresis of martensitic transformation as compared to the alloy without Nb addition from 22 to 50 °C with an increase in Af temperature from −5 to 22 °C.

Fabrication of Thermal Plasma Sprayed NiTi Coatings Possessing Functional Properties

Thick NiTi shape memory alloy coatings (300–500 µm) were produced on graphite and AISI 304 substrates by radio frequency inductively-coupled plasma spray technology (RF-ICP) from feedstock NiTi powders. Their microstructure as well as chemical and phase composition were characterized and a methodology for the characterization of functional shape memory properties of the thick coatings was developed. The coatings exhibited cubic to monoclinic martensitic transformation and shape memory effect. The presented results prove that NiTi coatings with functional thermomechanical properties can be easily produced on structural materials by RF-ICP. Further optimization will be needed to prepare NiTi coatings with better microstructural and chemical homogeneity.

Preparation and Electron-Beam Surface Modification of Novel TiNi Material for Medical Applications

A new approach to fabricate TiNi surfaces combining the advantages of both monolithic and porous materials for implants is used in this work. New materials were obtained by depositing a porous TiNi powder onto monolithic TiNi plates followed by sintering at 1200 °C. Then, further modification of the material surface with a high-current-pulsed electron beam (HCPEB) was carried out. Three materials obtained (one after sintering and two after subsequent beam treatment by 30 pulses with different pulse energy) were studied by XRD, SEM, EDX, surface profilometry, and by means of electrochemical measurements, including OCP and EIS. Structural and compositional changes caused by HCPEB treatment were investigated. Surface properties of the samples during their storage in saline for 10 days were studied and a model experiment with cell growth (MCF-7) was carried out for the unmodified sample with an electron beam to detect cell appearance on different surface locations.

Stannous chloride (SnCl2) and stannous sulfate (SnSO4) synthesis from tin powderization waste

The necessity of finding a way to utilize Sn metal from tin powderization waste as effectively and efficiently as possible has risen because of the large number of industrial by-products of Sn waste and the broad applications of tin chemicals in the world. Stannous chloride (SnCl2) and stannous sulfate (SnSO4) are tin-derived compounds in which their applications are in various fields, and one of which is catalysts. Catalyst products produced from the two compounds are STO (Sulfated Tin Oxide) catalyst. In this study, tin powderization waste was used as raw material for the synthesis of SnCl2 and SnSO4. The purpose of using tin waste is an effort to create the Sustainable Development Goals (SDG) program launched by the United Nations to obtain a sustainable consumption and production system. Tin powder from the off-spec product of the tin powderization process can be used as raw material to manufacture tin-derived chemical compounds. Overall, the process of developing tin products will produce a non-waste system (zero waste). The optimum conditions to synthesize SnCl2 are as follows; the tin powder particle size is 500 mesh with HCl 12 M at 80°C with a yield percentage of 95%. The synthesis of SnSO4 with the reaction of SnCl2 + (NH4)2SO4 can be carried out using stirring techniques. The results of the FT-IR spectrometer showed a spectrum of sulfate groups in the region ~ 1181 cm−1.

Influence of Secondary Component Hardness When Cold Spraying Mixed Metal Powders on Carbon Fiber Reinforced Polymers

In previous studies at McGill University, tin has successfully been cold sprayed onto carbon fiber reinforced polymers (CFRPs) and, with the idea of improving the coating conductivity, other metal powders (aluminum, copper and zinc) were added to tin and also sprayed. Results indicated that addition of any of the aforementioned secondary components (SCs) provided a noticeable increase in deposition efficiency (DE); it was hypothesized that a tamping mechanism might explain the improvement. In this study, aluminum and several aluminum alloys (5083, 6061, 7075) were mixed with tin powders to understand how the hardness of secondary components with similar densities may affect the deposition of tin on CFRPs. The top-surface and cross section of the coatings were examined, and DE and coating thicknesses were measured. Profilometric data were acquired on some coating top surfaces, as well as directly on some substrates after coatings peeled off. Mixing tin with other metallic powders is discussed and a refined “crack filling” mechanism related to SC hardness is explored as an improvement mechanism in the cold spraying of mixed powders on CFRPs.

Synthesis of 1‐(3H)isobenzofuranone compounds by tin powder promoted cascade condensation reaction

An efficient approach for the construction of phthalide compounds is developed through tin powder mediated cascade condensation reaction of 2‐formylbenzoic acids with allyl bromides or α‐bromoketone under mild reaction conditions. This method is easy to operate and can tolerate various functional groups to give the corresponding phthalides in good to excellent yields. The phthalides produced from α‐bromoketone can be further transformed to 3,3a‐dihydro‐8H‐pyrazolo[5, l‐a]isoindol‐8‐one and 8H‐pyrazolo[5, l‐a]isoindol‐8‐one.

Simultaneous Determination of Ultra-trace Pt, Pd, Rh and Ir in Geochemical Samples by Inductively Coupled Plasma Mass Spectrometry Following Tin Fire Assay Preconcentration and Microwave Digestion

Background: Platinum (Pt), palladium (Pd), rhodium (Rh) and iridium (Ir) are platinum group elements (PGEs) and also important elements of geochemistry and environmental chemistry with the similar physic-chemical properties, which have been widely used in industry and laboratory. However, due to the low abundance and inhomogeneous distribution in natural ore as well as the nugget effect, the accurate determination of PGEs has been a challenge to analytical chemistry. Methods: In this work, a novel fire assay method was reported for the determination of ultra-trace Pt, Pd, Rh and Ir in geochemical samples. Tin powder (Sn) instead of stannic oxide (SnO2) was used as a fire assay collector to reduce the melting temperature from 1250°C to 1050°C, the escape of molten material caused by high temperature was successfully avoided. Tin bead was compressed into thin slice and dissolved by HCl. For the target Pt, Pd, Rh and Ir, HCl insoluble substance such as PtSn4, PdSn4, RhSn4 and Ir3Sn7 were formed and separated from matrix by filtering. The metal compounds precipitate together with filter paper were microwave-assisted completely digested by aqua regia (50%, v/v), thence the sample solution was determined by inductively coupled plasma mass spectrometry (ICP-MS). Results: Compared with nickel oxide and lead oxide in nickel sulfide /lead fire assay, the reagent blank of tin powder were relatively low and could be directly employed in tin fire assay to collect Pt, Pd, Rh and Ir without purifying. Moreover, the harm of nickel oxide and lead oxide to the analyst and environment was avoided by using the non-toxic tin powder. The decomposition method of chromite and black shale was investigated as well as the amount of tin powder and flour, microwave digestion program for the determination of Pt, Pd, Rh and Ir were optimized. Besides, the influence of mass spectrum interference of co-existing elements was discussed and the standard mode and kinetic energy discrimination collision pool mode were compared. Under the optimal conditions, excellent curve fitting of Pt, Pd, Rh and Ir were obtained between 0.01~100 ng mL-1, with the correlation coefficients exceeding 0.9996. The detection limits were from 0.003 ng g-1 to 0.057 ng g-1. Conclusion: The developed method was applied to analyze the Chinese Certified Reference Materials and the determined values were in good agreement with the certified values.

Physicochemical properties of Tin (IV) oxide synthesized by different methods and from different precursors

The physicochemical properties of SnO2 obtained by different methods (sol–gel, solvothermal and CVD synthesis) from different precursors were investigated. The synthesized samples were characterized by X-ray diffraction analysis, electron spectroscopy, FTIR, low-temperature nitrogen adsorption–desorption and their optical bandgap and volt-ampere characteristics were determined. It was shown that the synthesis method and its parameters have a significant effect on the properties of the obtained SnO2 powders. The type of reaction medium significantly affects structural and adsorption characteristics of samples. SnO2 synthesized by the solvothermal method is characterized by the smallest crystallite sizes, larger specific surface, and more diverse structural characteristics in comparison with the powders obtained by sol–gel and CVD methods. Mesoporous powders of tin (IV) oxide were obtained using sol–gel method, macroporous SnO2 monocrystalline powders were produced by CVD method. The found values of the optical bandgap for the tin (IV) oxide, obtained by different methods, differ from the theoretical bandgap value. The influence of all parameters on the electrical properties of SnO2 was observed.

Studies on the Reversibility of Electrolytic Tin Powder Obtained from an Ionic Liquid

Studies on the Reversibility of Electrolytic Tin Powder Obtained from an Ionic Liquid

Effect of Nano-Silica Volume Reinforcement on the Microstructure, Mechanical, Phase Distribution and Electrochemical Behavior of Pre-Alloyed Titanium-Nickel (Ti-Ni) Powder

Titanium-Nickel pre-alloyed powder was reinforced with Nano-Silica in 2%, 4% , 6% and 8 wt. % due to effectiveness of Nanoscale ceramic Reinforcement in improving the properties of Metals and Alloys. The compositions of the Pre-Alloyed powders and Nano Silica Approximately 50 nm in diameter and spherical in shape were weighed and mixed in Planetary Ball Mill followed by compaction at 50 MPa using a Uniaxial Compaction machine The green pellets obtained were sintered in Argon Environment for 5 hrs and allowed to furnace cool. The pellets were then sectioned through their cross-section for slices 3 mm thick followed by Cold-mounting and Soldering followed by cold mounting additionally. The Samples were analyzed via X-Ray Diffraction (XRD) for phase distribution as a function of variation in nano-Silica reinforcements and Microstructural analysis was performed via Optical Microscope. The effect of Volume percentage on the densification was determined via Archimedes principle and Micro-Vickers hardness was used for mechanical Evaluation. The Electrochemical Properties were evaluated using Potentio-Dynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) in neutral salt solution (3.5% NaCl). The results indicated increasing dissolution of the TiNi phase into intermetallic Titanium-rich and Ni-rich phases in the matrix and hardening due to the Nano-Silica effect of Grain Boundary impingement and phase dissolution of Equiatomic phase and mixed behavior in Corrosion properties as determined by the electrochemical techniques whereas densification decreased due to poor plasticity of Nano-Silica and hinderance in diffusion during the sintering process.

Experimental investigation on the effect of melt delivery tube position on liquid metal atomization

Metal powders are often made by gas atomization of liquid metal. During the process, liquid metal which flows from a melt delivery tube (MDT) is atomized by high speed gas discharging from a gas nozzle. In this work, the effect of the melt delivery tube position on atomization outcomes such as the yield, mass median diameter, and spread of the particle size distribution, is studied experimentally. A melt atomization setup (pilot-scale) is used to produce tin powder by gas-atomization. Three MDT positions, namely, intruded, extruded and flush with respect to the gas nozzle, are chosen for this study. Three pressure regimes (atmospheric, aspiration and pressurization) are established by varying the relative distance between the MDT and the gas nozzle exit for the three positions. Experimental investigations revealed that the intruded position produces powder with lower mean particle sizes and lower spread than the extruded configuration. The intruded position also gives a significantly higher yield compared to the extruded and flush positions at low gas flow rates, and hence appears to be the most suited for metal atomization using a free-fall configuration.

Effects of printing volumetric energy densities and post-processing treatments on the microstructural properties, phase transformation temperatures and hardness of near-equiatomic NiTinol parts fabricated by a laser powder bed fusion technique

Equiatomic and near-equiatomic NiTinol alloys, mainly due to the exhibition of adjustable mechanical and thermal shape memory properties, are widely exploited to produce different smart and functional devices. Laser powder bed fusion technique was used in this research to process dense NiTinol parts from a prealloyed near-equiatomic NiTi powder, using three different volumetric energy densities. In the next step, samples, processed using a specific set of printing parameters, were annealed using two different procedures. Effects of different used processing volumetric energy densities and post-processing heat treatments on the microstructural properties, phase composition, crystallographic information, phase transformation behavior and hardness of the processed samples were investigated. As-printed Parts with Ni contents ranging from 55.12 to 55.27 wt%, density higher than at least 96% of theoretical and a similar phase structure as that of used powder, dominated by austenitic NiTi, were obtained. Applying a hot isostatic processing treatment at 1100 °C for 4 h or annealing the samples in a pressureless sintering furnace, working under a vacuum environment at the same temperature and holding time, had significant effects on the properties of the printed parts. These treatments, in addition to increasing the density of the printed samples, their average grain size and reducing the residual stresses, shifted the phase transformations to lower temperatures. These results suggest that post-printing heat treatments affect and, as similar to NiTinol alloys having Ni contents above 55.7 wt%, can be used as a strategy to alter the phase transformation temperatures of printed less Ni-rich near-equiatomic NiTinol alloys and consequently obtain NiTinol parts suitable for different applications.

Optimization Process In The Synthesis of Stannous Chloride (SnCl2) by Redox Method In The Context of Downstream Tin Derivative Product

Indonesia has been known as the Tin Island in Southeast Asian Tin Belt region. This makes Indonesia listed as the second biggest tin producer in the world after China, with production reached 33.444 metric tons. However, 95% of tin which has been exported is still in the form of bars, not the optimal downstream tin derivative products, especially in the form of tin chemicals such as SnCl2. It turned out that tin chemical products are imported to meet the needs of domestic industry. In 2014, tin import reached USD 200 million. As one of the downstream products of tin derivatives, SnCl2 can be used as a catalyst, reducing agent, and as the main ingredient for other tin derivative products. This research was conducted based on the demand of industry, PT Timah Industri, to study the synthesis of SnCl2 powder in optimum conditions with redox method. The tin powder was dissolved in concentrated HCl heated on a hotplate, with variations in the particle size of the tin, HCl concentration and the reaction temperature. Differential Thermal Analysis (DTA) was carried out at 8000C with a heating rate of 100Cmin-1. The morphological structure of SnCl2 powder can be determined using 3D-Optical Microscope VHX-5000. As for the SnCl2 phase, it can be identified using the Rigaku SmartLab X-ray diffraction. This attempt has succeeded in synthesizing SnCl2 powder at optimum conditions with a yield percentage of 95%.

Growth of ZnSnO nano structures for thermopower applications by thermal evaporation with and without oxygen precursor

In this manuscript, we have reported the crystal quality control of ZnSnO nanostructures during thermal evaporation growth in the presence and absence of oxygen gas during the growth process. To test this hypothesis, we have prepared two set of samples by evaporating Zn and tin powders (5:1 ratio) on Si substrate under similar growth conditions. But one set of samples was prepared in the presence of oxygen gas with a flow rate of 100sccm while other set of samples was grown under the absence of oxygen gas. Structural study revealed the formation of hexagonal structures of ZnSnO for both sets of samples while the Raman spectroscopy also supported the XRD data. But the observed morphology (SEM images) showed the different behavior of samples i. e porous structure of the samples grown using oxygen precursor while the nano-needle shape morphology was observed for the sample grown without oxygen. Thermo power measurements demonstrated that sample grown using oxygen precursor possess the highest value of Seebeck voltage along with other thermoelectric parameters when we compared with the samples grown without the presence of oxygen gas. The highest thermo power ability was related to the formation of porous structures which is a major cause of mobility enhancement.

Dense TiN‐Ni cermets with improved sinterability, microstructure, and mechanical properties using Ni‐coated TiN powders

AbstractTo solve the poor sinterability and wettability between TiN ceramic and pure metal via using coated composite powders, dense TiN‐Ni cermets with uniform microstructure and fine grains were developed at a low sintering temperature of 1300℃ in this work. TiN powders were firstly activated in a strong acid solution, in order to achieve a step‐like surface; Ni‐coated TiN powders showed an uniform and controllable morphology. Two types of TiN‐Ni cermets based on conventional milled powders and Ni‐coated TiN composite powders were fabricated by spark plasma sintering (SPS), and used for the comparison concerning the sintering behavior, microstructure and related mechanical properties. Results showed that Ni‐coated TiN composite powders helped to improve the sinterability between ceramic and metal, which is rather beneficial to obtain dense TiN‐Ni cermets with homogeneous microstructure and high mechanical properties. Compared to those of conventional TiN‐Ni, the relative density, Rockwell hardness and fracture toughness increased from 84.9% to 96.6%, 80.2 to 84.3, and 10.2 MPa·m1/2 to 14.7 MPa·m1/2, with a rather low sintering temperature of 1300 ℃, respectively.