Li-ion storage properties of two-dimensional titanium-carbide synthesized via fast one-pot method in air atmosphere

Structural bidimensional transition-metal carbides and/or nitrides (MXenes) have drawn the attention of the material science research community thanks to their unique physical-chemical properties. However, a facile and cost-effective synthesis of MXenes has not yet been reported. Here, using elemental precursors, we report a method for MXene synthesis via titanium aluminium carbide formation and subsequent in situ etching in one molten salt pot. The molten salts act as the reaction medium and prevent the oxidation of the reactants during the high-temperature synthesis process, thus enabling the synthesis of MXenes in an air environment without using inert gas protection. Cl-terminated Ti3C2Tx and Ti2CTx MXenes are prepared using this one-pot synthetic method, where the in situ etching step at 700 °C requires only approximately 10 mins. Furthermore, when used as an active material for nonaqueous Li-ion storage in a half-cell configuration, the obtained Ti2CTx MXene exhibits lithiation capacity values of approximately 280 mAh g−1 and 160 mAh g−1 at specific currents of 0.1 A g−1 and 2 A g−1, respectively.

Effect of Sintering Parameters on the Microstructure and Properties of Cu-Ti3AlC2- Gr Composite

In this work, Copper-Titanium Aluminium Carbide (MAX Phase) – Graphene Composites of desired sizes were prepared by mechanical alloying and Powder Metallurgy route. Sintering was carried out at different temperatures and times and the effect of these sintering parameters on the microstructure of the developed composite and the mechanical and electrical properties were investigated. The microscopic examination reveals that increase in sintering temperature resulted in a properly bonded composite structure. The increase in sintering temperature and time increases the hardness and the wear resistance of the developed composite. Though the density and electrical conductivity shows an increasing trend initially, with higher Sintering temperature, a slight decrease is observed because of the presence of voids in the structure.

Effective functionalisation of carbon nanotubes for reinforcement application in liquid state processed aluminium composites: A relatively greener approach

This paper outlines an innovative approach to functionalise multiwall carbon nanotubes at a reduced functionalisation time and energy consumption, preserving their structural integrity, with objective of potential application of the carbon nanotubes as reinforcement in aluminium matrix composites processed through liquid state method. Longstanding problems of aluminium carbide formation as reaction by-product in aluminium matrix composites is expected to be reduced by reinforcing the carbon nanotubes functionalised through the developed method. Carbon nanotube surfaces were oxidised following four different methods using solutions of different acids at different parametric combinations, and the best possible method was identified through dispersion stability test, Fourier-transform infrared spectroscopy, scanning electron microscopy, Raman spectroscopy and thermogravimetric analysis. Results revealed that primary oxidation by 6M HNO3, followed by subsequent oxidation by weak acid H2O2 generated functionalised carbon nanotubes with satisfactory dispersion stability, preserved graphitic structure, high degree of structural integrity, less structural distortion and less carbon nanotube fragmentation.

Aluminium Silicon Hypereutectic Alloys from 6063 Alloy’s Black Dross Using Silicon Lumps and Flux

The study on the extraction of Aluminium metal from industrial waste like aluminium dross (black dross) to be used in the production of aluminium silicon hypereutectic alloy and testing the resulted hypereutectic alloy chemically, physically, and mechanically has been carried out. The amount of the black dross used undergoes pretreatment by immersion the dross samples in tap water and settled overnight to assure the maximum separation of nonmetallic, aluminium nitride, aluminium carbide and aluminium oxide, the properties of tap water used for pretreatment dross samples was recorded to see the effect of dross content on the tap water. The pretreated dross samples were dried in electric furnace at 60ₒc for 2hrs then samples of 60 gm remelted in a graphite crucible and amount of flux(sodium chloride, potassium chloride, cryolite and calcium fluoride) (1:1) is added, then different quantities of silicon lumps are added too. The graphite crucible is put in the carbolite furnace at 800ₒc for 30 minutes. The molten aluminium silicon is poured in specific moulds for the chemical and physical examination, which shows the formation of aluminium silicon hypereutectic alloys with good chemical, physical and mechanical properties. Thus the dross is a great source for both aluminium metal high grade and aluminium silicon hypereutectic alloy.

New quaternary carbide Mg1.52Li0.24Al0.24C0.86as a disorder derivative of the family of hexagonal close-packed (hcp) structures and the effect of structure modification on the electrochemical behaviour of the electrode

Magnesium alloys are the basis for the creation of light and ultra-light alloys. They have attracted attention as potential materials for the accumulation and storage of hydrogen, as well as electrode materials in metal-hydride and magnesium-ion batteries. The search for new metal hydrides has involved magnesium alloys with rare-earth transition metals and doped byp- ors-elements. The synthesis and characterization of a new quaternary carbide, namely dimagnesium lithium aluminium carbide, Mg1.52Li0.24Al0.24C0.86, belonging to the family of hexagonal close-packed (hcp) structures, are reported. The title compound crystallizes with hexagonal symmetry (space groupP\overline{6}m2), where two sites with \overline{6}m2 symmetry and one site with 3m. symmetry are occupied by an Mg/Li statistical mixture (in Wyckoff position 1a), an Mg/Al statistical mixture (in position 1d) and C atoms (2i). The cuboctahedral coordination is typical for Mg/Li and Mg/Al, and the C atom is enclosed in an octahedron. Electronic structure calculations were used for elucidation of the ability of lithium or aluminium to substitute magnesium, and evaluation of the nature of the bonding between atoms. The presence of carbon in the carbide phase improves the corrosion resistance of the Mg1.52Li0.24Al0.24C0.86alloy compared to the ternary Mg1.52Li0.24Al0.24alloy and Mg.

Effect of c-BN Size and Content on the Self-Propagating High-Temperature Synthesis of c-BN Composites Bonded with Ti-Al-C System Multiphase Products

A mixture of Ti, Al, graphite and c-BN powders was used as raw material to fabricate Ti2AlC matrix-bonded c-BN composite using the self-propagating high-temperature synthesis (SHS) method. The effect of c-BN size and content on the fabrication of the composites was investigated. The results show that Ti2AlC matrix-bonded c-BN composites can be obtained by SHS. c-BN content and size evidently affected the phase composition and microstructure characteristic of the composites. At 10–30% c-BN (120/140 mesh) content, the product phases were Ti2AlC, Ti3AlC2, Al3Ti, TiN, TiC, AlN, graphite and TiB2. A dense transition layer with a thickness of about 10 µm showed the interface between c-BN and the matrix. However, Al peaks appeared, and the titanium aluminium carbide peak became weak in the samples containing 40% and 50% c-BN. c-BN was unequally enwrapped by one coating with a thickness of about 2 µm. The main product phases of the samples were Ti2AlC, Ti3AlC2, Al3Ti, TiN, TiC, AlN, graphite and TiB2 in the products with different c-BN sizes. The addition of coarse c-BN particles (80/100, 120/140 and 170/200 mesh) yielded a transition layer with a thickness of approximately 10 µm on the interface and Ti2AlC main phase matrix. The finer the particle size, the greater the reaction activity. When c-BN was finer (20 μm), c-BN more easily reacted with Ti and Al to form TiN, AlN and TiB2. The synthesis of Ti2AlC was obviously inhibited.