in this research, fabrication of an in-situ composite via aluminothermic combustion synthesis in al–v2o5 system has been investigated. for this purpose, the mixed powders of al and v2o5 with molar ratio of 28 to 3 were ball milled and then compressed. differential thermal analysis was used to evaluate the temperatures of phase transitions. using the peak temperature of the reactions, the sample...

We explored the B-C-O system at pressures in the range 0-50 GPa by ab initio variable-composition evolutionary simulations in the hope of discovering new stable superhard materials. A new tetragonal thermodynamically stable phase B4CO4, space group I4[combining macron], and two low-enthalpy metastable compounds (B6C2O5, B2CO2) have been discovered. Computed phonons and elastic constants show th...

X-ray photoelectron spectroscopy (XPS) technique was employed to characterize Al2O3-TiO2 support and MoO3/Al2O3TiO2 catalyst calcined at different temperatures from 773 to 1073 K. The Al2O3-TiO2 (1:1.3 mole ratio) binary oxide support was obtained by a coprecipitation procedure with in situ generated ammonium hydroxide. A nominal 12 wt.% MoO3 was impregnated over the calcined (773 K) support by...

One-dimensional γ-Al2O3 nanofibers were modified with Nb2O5 to be used as an efficient heterogeneous catalyst to catalyze biomass into 5-hydroxymethylfurfural (5-HMF). At low Nb2O5 loading, the niobia species were well dispersed on γ-Al2O3 nanofiber through Nb-O-Al bridge bonds. The interaction between Nb2O5 precursor and γ-Al2O3 nanofiber results in the niobia species with strong Lewis acid si...

9 The synthesis of (Ti1-xZrx)B2-Al2O3, (Ti1-xHfx)B2-Al2O3 and (Zr1-xHfx)B2-Al2O3 10 (x=0, 0.5 and 1) powder nanocomposites via a mechanochemical method using TiO2, ZrO2, 11 HfO2, HBO2 and Al as the raw materials was investigated. The formation of the 12 nanocomposites proceeds via a mechanically-induced self-sustaining reaction (MSR) process 13 that involves several simultaneous reactions. The ...

We study the coherent and semi-coherent Al/α-Al2O3 interfaces using molecular dynamics simulations with a mixed, metallic-ionic atomistic model. For the coherent interfaces, both Al-terminated and O-terminated nonstoichiometric interfaces have been studied and their relative stability has been established. To understand the misfit accommodation at the semi-coherent interface, a 1-dimensional (1...