Thermal stability and structural properties of Ta nanopowder synthesized via simultaneous reduction of Ta2O5 by hydrogen and carbon

Abstract

Tantalum nanoparticles have been synthesized by the single-step chemical reaction route. Simultaneous reduction of Tantalum Pentoxide (Ta 2 O 5 ) with the in situ produced hydrogen and carbon at 600°C is a new approach for the production of Ta nanopowder. DH values obtained from thermodynamic calculations are used to predict the entire mechanism of reduction of bulk Ta 2 O 5 into Ta nanoparticles. The results of X-ray diffraction studies show that the final product consists of predominately nano a-Ta with b-Ta as the minority phase. The lattice strain in the final product was calculated using Williamson-Hall formula. The effect of lattice strain on thermal stability of the samples was analyzed by differential scanning calorimetry and thermal gravimetry in the air atmosphere. The morphology and particle size distribution of Ta nanosized powders have been analyzed by scanning electron microscope and transmission electron microscope. The results show that average crystallite size of the product Ta nanopowder is about 2-7 nm.

Tantalum-doped Mesoporous Bioactive Glass Fibers and Powders for Hemostatic Applications

“…When exposed to blood, amorphous silica shows stronger coagulation capabilities than crystalline silica [56]. Crystalline silica [226] and Ta2O5 [227] show high narrow peaks in the region of 20-30º on WAXRD patterns while amorphous silica shows a broad peak in this region. The presence of wide peaks in the region of 20-30º for fibre samples (Figure 6-2) signify their amorphicity.…”

Synthesis of carbon coated tungsten carbide nano powder using hexane as carbon source and its structural, thermal and electrocatalytic properties

“…4 e Change of DG with temperature during decomposition of hydrocarbon gas. i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 5 ) 1 e1 0 report [52]. Thus, during the heating of the samples, there are two processes that are taking place simultaneously: (i) oxidation of W (400 Ce600 C) which gives rise to gain in mass and (ii) oxidation of carbonaceous residue (600 Ce750 C) which results in decrease in mass.…”

Formation mechanism of Ti4O7 phase prepared by carbothermal reduction reaction

“…In this study, the unknown thermodynamic data were firstly assessed by the expression satisfactorily. The CRR process was carried out by a thermogravimetric (TG) instrument, which was a common method for analyzing the mechanism of CRR . The activation energy of different stages was also discussed.…”

“…The CRR process was carried out by a thermogravimetric (TG) instrument, which was a common method for analyzing the mechanism of CRR. 28,29 The activation energy of different stages was also discussed. Furthermore, the phase evolution and the microstructures of titanium oxides calcined at different temperatures were systematically investigated by X-ray diffraction (XRD) and transmission electron microscope (TEM) respectively.…”