Two preparation methods (wet saturation impregnation with vanadyl acetylacetonate and ball-milling of γ-Al2O3 with crystalline V2O5) were applied to produce two sets of VOx/γ-Al2O3 catalysts with increasing vanadium loadings. Materials from both sets were characterized by XRD, SEM, Raman, TPR and UV/Vis-DRS to elucidate the influence of the preparation method on the morphology of VOx species an...

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...

Previous research on the laser damage resistance of thin films deposited by atomic layer deposition (ALD) is rare. In this work, the ALD process for thin film generation was investigated using different process parameters such as various precursor types and pulse duration. The laser-induced damage threshold (LIDT) was measured as a key property for thin films used as laser system components. Re...

A multiscale simulator for alumina film growth inside a nanoporous material during an atomic layer deposition process is developed. The model combines a continuum description at the macroscopic level of precursor gas transport inside a nanopore during exposure to each of the two precursor species (trimethyaluminum and water) with a lattice Monte Carlo simulation of the film growth on the micros...

alumina is one of the most widely used ceramic materials as catalysts, catalyst supports and absorbents, and also wear resistant coating. this study focused on fabricating and characterizing of alumina ceramic nanoparticles fabricated using new and simple sol-gel method. aluminium oxide (al2o3) nanoparticles were synthesized by iron (iii) nitrate 9-hydrate as precursor. physicochemical properti...

A process is described which involves infiltration of aluminum nitrate into partially sintered (porous) zircon bodies. Infiltration kinetics were studied using infiltration curves with two distinct regions. The final infiltrated samples were sintered at 1600 °C for 2 h and yielded specimens containing the tetragonal zirconia.The experimental results show that in spite of the similar porosity of...

A first-principles study of the vibrational modes of PbTiO3 in the ferroelectric tetragonal phase has been performed at all the main symmetry points of the Brillouin zone ~BZ!. The calculations use the local-density approximation and ultrasoft pseudopotentials with a plane-wave basis, and reproduce well the available experimental information on the modes at the G point, including the LO-TO spli...

In this study, two new Ni/La-Al2O3 catalysts were prepared by a sol-gel method, with different aluminium precursors (aluminium triisopropoxide and aluminium nitrate). The catalysts were characterized by scanning electron microscope (SEM), X-ray fluorescence (XRF), X-ray diffraction (XRD), BET specific surface area, and particle size analysis (PSA) techniques. The BET results showed that the par...