Tin Powder Research Articles

Si–TiN alloy Li-ion battery anode materials prepared by reactive N2 gas milling

Si–TiN alloys were prepared by reactive gas mechanical milling of Si and Ti powders in N2(g) for use as anode materials in Li-ion cells. This is a low-cost and simple method to prepare Si–TiN anode materials. As a comparison, Si–TiN alloys were also synthesized more conventionally by ball milling Si and TiN powders in Ar. Both Si–TiN alloys have similar phase compositions, however the Si–TiN alloys prepared by N2 reactive gas milling have a more homogenous TiN distribution at the nanometer-scale. As a consequence, Si–TiN alloys prepared by N2 reactive gas milling where much more resistant to Li15Si4 formation during cycling in Li-cells, resulting in improved cell performance.

Metal open-cell foams with periodic topology fabricated by spark plasma sintering

A novel manufacturing approach to controlling the pore structure of metal open-cell foams has been conceptually demonstrated based on a periodic arrangement of high temperature porogens (a.k.a. space-holders). A process integrating structured porogen replication and spark plasma sintering (SPS) was developed to fabricate metal open-cell foams exhibiting increased control over the pore size, shape, and position. A sacrificial porogen template constructed of commercially available copper spheres arranged in a hexagonal close-packed pattern was co-sintered with nickel-titanium (NiTi) powder using SPS and subsequently leached using nitric acid. The repeatability of the foam fabrication process was investigated by characterizing the density, pore structure, and mechanical properties of the resultant open-cell foams. Spatially, the foams displayed uniform, well-replicated pore structures with a high degree of interconnectivity. During compression testing the open-cell foams exhibited unexpected brittle behavior with a high variability in ultimate strength, believed to be caused by the initiation and inter-particulate propagation of cracks through the matrix leading to sudden specimen failure.

Pengaruh Variasi Arus dan Waktu terhadap Pembuatan Serbuk Timah Putih (Sn) melalui Proses Elektrodeposisi

Manufacture of powder metallurgy through the process of electrolysis, resulting in the phenomenon of deposition on the cathode. Electrolysis process produces high purity but many compounds decompose participating will affect its purity. Pulverizing tin (Sn) is done by varying the amount of current (5 A , 6 A and 7 A) and processing time (20 minutes , 25 minutes and 30 minutes) with variable fixed temperature of 50 ° C and solution concentration of 0.01 M. Electrode used is stainless steel 304 as the cathode and tin (Sn) as the anode. Powder tin (Sn) generated reaches 80 % , the most current efficiency is obtained from the current 6 A with a time of 20 minutes and the lowest energy consumption derived from the current of 5 A at 20 , 25 and 30 minutes at 4.6 KWH / kg Sn. From the results obtained are expected to be a material consideration in producing powder tin (Sn).

Tin powder promoted synthesis of trifluoroethylamine‐containing 3,3′‐disubstituted oxindoles

An efficient and facile approach for the construction of trifluoroethylamine‐containing 3,3′‐disubstituted oxindoles or 3‐spirooxindoles is developed through the reaction of isatins, 2,2,2‐trifluoroethylamine hydrochloride and allyl bromides or 2‐(bromomethyl)acrylic ester mediated by tin powder. This method uses simple and commercially available 2,2,2‐trifluoroethylamine hydrochloride as a trifluoroethylamine building block and avoids the use of toxic allylstannanes.

Features of the Plastic Flow of Sintered Al–12Si–xSn Alloys

The feasibility of obtaining a self-lubricating composite material of the Al–Sn system with the alloyed matrix by the liquid-phase sintering of compacts obtained from the mixture of powders of the eutectic Al–12Si alloy and tin powders was investigated. The porosity of the raw compacts was ~10%; the strength of the sintered Al–12Si–xSn composites was significantly lower as compared with the additive value. The porosity of compacts decreased and the strength reached the theoretical value after additional hot densification of the sintered samples at 200 and 250°C (lower and higher than the tin melting point). The plasticity of composites under compression after densification increased as well and showed its maximum in the composite with 10–20% Sn. Analysis of the compression curves showed that, for the sintered composites, the long linear stage of plastic flow with a low coefficient of strain hardening is a characteristic feature. With the increase in the tin content, the stage of the linear flow shortens and with the 40% Sn concentration disappears. The transcrystalline localized flow and material cracking is observed before fracture.

Macrostructure and Strength of the Al–Zn–Sn Composite Produced by Liquid-Phase Sintering of the Al–Zn Alloy and Pure Tin Powder Mixture

Features of liquid-phase sintering compacts made of powders of the Al–10Zn alloy and tin of the PO 2 brand, as well as the influence of sintering modes on the structure and strength of forming antifriction composite of the (Al–10Zn)–40Sn composition, are studied. The porosity of the initial green compacts varies in a range of 5–18%. Compacts are sintered in a vacuum furnace under a residual gas pressure no higher than 10–2 MPa. The sintering temperature varies in a range of 550–615°C and corresponds to the partial wetting of aluminum with liquid tin. The sample holding time at a specified temperature is from 30 to 180 min. Structural studies show that the particle size of the aluminum and tin phases increases with an increase in the sintering temperature and holding time. The mechanical properties of sintered composites are determined by their compression testing. The samples are cut from the middle of sintered compacts. It is established that samples made of the (Al–10Zn)–40Sn sintered alloy possess high ductility and exhibit higher strength when compared with the Al–40Sn sintered composite with a pure aluminum matrix due to the more intense strain hardening of a matrix at a high deformation. It is found that sintered composites prepared from high-density green compacts subjected to preliminary low-temperature holding possess the highest strength. Based on the results, it is concluded that the liquid-phase sintering in a specified temperature range makes it possible to prepare (Al–10Zn)–40Sn composites with a bound aluminum matrix effectively preventing the strain localization in soft tin-based phase interlayers. The optimal sintering temperature should not exceed 600°C.

Electrochemical hydrogenation after mechanical activated near equiatomic Ti-Ni powder

It has been studied an effect of mechanical activation in a planetary ball milling on the electrochemical hydrogenation of Ti-Ni powder near equiatomic content. It has been shown that average particle sizes measured by scanning electron microscope decreased from 11.1 to 7.8 μm up to 30 s mechanical activation, then increased to 33.2 μm for 300 s activation. Beside, with an increase in the time of mechanical activation was formed state with small the coherently diffracting domain which correspond to quasi-amorphous state of material. It has been shown that after hydrogenation, the particle size distribution did not change. There is an incubation time hydrogenation for mechanical activation, when hydrogenation is not occurring. Mechanical activation for more than 30 s leads to the formation of the Ti2NiHx phase based on the Ti2Ni and 50 s activation is sufficient to form the Ti2NiH0.5 stoichiometry. For a longer mechanical activation a phase with the stoichiometry Ti2NiH0.85 was formed and to obtain the Ti2NiH stoichiometry it is necessary to carry out activation for 4.5 hours.

Synthesis of Titanium Dioxide Nanopowder via Oxidative Hydrolysis of Titanium Nitride

A new technique has been proposed for TiO2 synthesis via oxidative hydrolysis of TiN powder. We have examined the effect of factors determining the rate of TiN dissolution (temperature, concentration, and nature of the oxidant) on the phase composition and particle size of resulting TiO2 powders and assessed the photocatalytic activity of the synthesized powders in comparison with commercially available photocatalysts.

Laser cladding NiCrBSi/TiN/h-BN self-lubricating wear resistant coating on Ti–6Al–4V surface

Self-lubricating wear resistant composite coating with TiN0.3, TiN and TiB as reinforcement phases, BN as lubricating phase were fabricated on the surface of Ti–6Al–4V alloy substrate by laser cladding with NiCrBSi, TiN and BN composite powders. The phase compositions, microstructure, interface metallurgical bonding and interdiffusion behavior between coating and substrate, microhardness, wear profile and tribological properties are investigated by x-ray diffractometer (XRD), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), electron backscatter diffraction technique(EBSD), microhardness tester and multi-purpose friction and wear testing machine, respectively. And the corresponding friction and wear mechanism is analyzed. Results show that the nickel-based composite powder containing TiN reinforcing phase and BN lubricating phase reacts to a composite coating which is densely bonded with the matrix and has no obvious defects such as pores and cracks. The section of the coating is smooth and the microstructure is fine, and the reinforcement phase is uniformly distributed in the coating with distributing the reinforcement phase uniformly in the coating. TiNX and BN in the coating are mainly in the form of black particles gathered into dendritic form. When the h-BN mass fraction is 5%, the average microhardness of the coating is about 967.1 HV, which is about 2.6 times higher than that of the substrate (370 HV). The friction coefficient and wear rate of the coating are obviously lower than that of the substrate, and the wear surface of the cladding layer is relatively smooth, and the wear resistance is remarkably improved.

Additive manufacturing of NiTi shape memory alloys using pre-mixed powders

This work presents a comparative study on the in-situ alloying of NiTi shape memory alloys (SMAs) by directed energy deposition (DED), selective laser melting (SLM) and selective electron beam melting (SEBM) processes using pre-mixed Ni-Ti powders. The influence of process parameters on the microstructural homogeneity, phase formation and thermomechanical properties of NiTi alloy has been systematically studied. DED could build solid NiTi alloys with good interlayer fusion and phase transformation characteristics. However, a substantial amount of uniformly dispersed Ti2Ni intermetallics can embrittle this material. SLM-built NiTi parts show a tradeoff between microstructural inhomogeneity and keyhole defects when the energy densities are varied. In addition, the strong exothermic reaction in Ni-Ti powder mixtures during printing can disturb the melt pool, making it challenging to elaborate this material and obtain desired phases by using SLM. Moreover, SEBM is found to be unsuitable to in-situ synthesize this highly reactive material due to the lack-of-fusion vs. powder-ignition dilemma in the mandatory preheating step. It is suggested to adopt DED to in-situ alloy NiTi parts when using the elementally blended powders as feedstocks.

Tin‐Mediated One‐Pot Preparation of β‐Trifluoromethyl‐β‐ acylhydrazonyl Carbonyl Compounds

AbstractA concise and efficient protocol for the preparation of β‐trifluoromethyl‐β‐acylhydrazonyl carbonyl compounds was developed from multicomponent one‐pot reactions of trifluoroacetaldehyde methyl hemiacetal, acylhydrazines and 2‐bromocarbonyl compounds in the presence of tin powder. The reactions can be carried out under mild reaction conditions to give the products in good to excellent yields.

Efficient and cost-effective method to synthesize highly purified Ti4AlN3 and Ti2AlN

Nitrides MAX have attracted ever-growing interest owing to its unique metallic and ceramic characteristics and properties. Here, we report on the synthesis of highly purified Ti2AlN and Ti4AlN3 powders from Ti, Al and TiN powders by a facile atmosphere sintering method. The obtained nitrides show highly pure phase and excellent layered structure. Except for the composition difference of raw materials, both the nitrides can be sintered and obtained by same sintering temperature and holding time, which thus makes less processing time and less usage of synthesis parameters as compared to previously synthesis methods. To our knowledge, present work is one of the few reports on synthesis of Ti4AlN3 and Ti2AlN using atmosphere sintering method. Furthermore, the lattice changes of the layered structure of Ti2Al[Formula: see text] ([Formula: see text]) were studied by changing the composition of [Formula: see text] position from the synthesis of Ti2AlCN and Ti2AlC, and the optimal formulation and synthesis mechanism of Ti4AlN3 were also studied.

Current-Assisted Sintering of Combustion-Synthesized β-SiAlON Ceramics

Current-assisted sintering of combustion-synthesized β-Si5AlON7, h-BN, and TiN powders was explored in comparison with conventional sintering. High relative density of product (above 92%) was achieved by using high-voltage electric discharge consolidation (HVEDC) and spark plasma sintering (SPS). Better results were obtained in case of SPS processing.

Tin Powder Promoted Synthesis of α-Trifluoromethyl Homoallylic Hydrazides

Tin Powder Promoted Synthesis of <i>α-</i>Trifluoromethyl Homoallylic Hydrazides

Laser cladding Ti-Ni/TiN/TiW+TiS/WS2 self-lubricating wear resistant composite coating on Ti-6Al-4V alloy

TiN reinforced Ni matrix composite coating with in-situ synthesized TiS lubricant phase were fabricated on Ti-6Al-4V alloy by laser cladding with NiCrBSi, TiN and WS2 powder mixtures. The phase compositions, microstructure, microhardness and tribological behaviors are investigated by X-ray diffractometer (XRD), scanning electron microscope (SEM) with energy dispersive spectrometer (EDS) as well as a multi-functional Tribometer. Effect of WS2 contents on the microstructure, microhardness and tribological properties were studied. And the corresponding wear mechanism was discussed. Results indicate that the hardness of the coating (about 900HV0.2) is significantly improved compared with substrate (370HV0.2). Coefficients of friction and wear rates of these coatings have been significantly reduced. Besides, laser-clad coating using the mixed powders of 50%Ni-30%TiN-20%WS2 has good anti-wearing and friction reducing effects, and the main wear mechanisms of that are abrasive wear and micro-plowing.

Influence of Cross Rolling on the Structure and Properties of a TiNi Powder Alloy. Part 2

Influence of Cross Rolling on the Structure and Properties of a TiNi Powder Alloy. Part 2

Selective electron beam melting of NiTi: Microstructure, phase transformation and mechanical properties

Recent years have witnessed extensive investigations of additively manufactured NiTi alloys using laser-source techniques. This study reports a selective electron beam melting process to make Ni-rich NiTi parts using the plasma rotating electrode processed pre-alloyed NiTi powder. Microstructures of the as-printed NiTi samples were investigated, including micro-morphology, phase constituent and texture. Chemical compositions (primarily oxygen and nickel) and martensitic transformation temperatures were compared between the in house made NiTi powders and as-printed NiTi samples. X-ray diffraction results show that the as-printed samples exhibit a dominant austenitic B2 phase and a minor in situ formed Ni4Ti3 phase. The as-printed samples demonstrate a strong B2 (001) orientation texture along the building direction. Differential scanning calorimetry results show asymmetric phase transformations: a two-step of B2 → R → B19′ phase transformation during cooling but a one-step B19′ → B2 transformation during heating. Excellent superelasticity and large reversible strain have been observed. The as-printed NiTi samples achieve a fracture tensile stress of 1411.0 ± 59.3 MPa and an elongation of 11.8 ± 0.9%. The observed tension-compression asymmetry has been also discussed.

Effect of helical rolling on the structure and properties of TiNi powder alloy. Part 1

Effect of helical rolling on the structure and properties of TiNi powder alloy. Part 1

Tin Powders Electrodeposition from Choline Chloride Based Ionic Liquid

Possibilities of tin powders obtainment from the choline chloride-ethylene glycol ionic liquid are considered. The tin reduction from an ionic liquid mechanism is confirmed via chronovoltametry, chronopotentiometry, transient potential and impedance spectroscopy methods. Said mechanism includes the trichlorostanite complexes reduction at current densities up to 5 mA / cm2, recovery from a polyanionic adsorbed layer at current densities of 5-12 mA/cm2 and recovery from a mixed layer including polyanions bound and by electrolyte ions at current densities exceeding 12 mA/cm2. Tin ions reduction from the mixed coating layer facilitates forming of encapsulated tin powder particles with shape of symmetrical dendrites. Powders obtainment from an ionic liquid allows to reduce the resulting powder dispersion.

Synthesis of Tin Powders Using Dynamic CRN Method

Dynamic carbotermal reduction-nitridation (DCRN) is a new approach developed to produce more effective ceramic powder production than classical static system of carbothermal reduction-nitridation (CRN) method. In this new technique of DCRN, powder is produced in a moving system and production takes place at relatively lower temperatures and/or shorter times than CRN method. This study examines production of TiN powder by the DCRN method. The granules were prepared using TiO2 and carbon black powders in the stoichiometric ratio (C/TiO2=2). TiN powders of sub-micron were obtained in a graphite reactor from the prepared granules under N2 gas flow. The effects of various test parameters were investigated for TiN synthesis, such as temperatures of reaction (1350-1450°C), reaction time (0.5-3 h), N2 gas flow rate (60-120 L/h) and reactor rotation speed (2-6 rpm). The phases and microstructures of the powders were characterized by XRD, SEM and FESEM analyses.