Nanoindentation has become a common technique for measuring the hardness and elastic–plastic properties of materials, including coatings and thin films. In recent years, different nanoindenter instruments have been commercialised and used for this purpose. Each instrument is equipped with its own analysis software for the derivation of the hardness and reduced Young’s modulus from the…
This work reports the synthesis at room temperature of transparent and colored WxSiyOz thin films by magnetron sputtering (MS) from a single cathode. The films were characterized by a large set of techniques including X-ray photoelectron spectroscopy (XPS), Rutherford backscattering spectrometry (RBS), Fourier transform infrared (FT-IR), and Raman spectroscopies. Their optical properties were determined by…
Herein we demonstrate improved mass transport through nano-particle one-dimensional photonic crystals of enhanced porosity. Analysis is made by impedance spectroscopy using iodine and ionic liquid based electrolytes and shows that newly created large pores and increased porosity improve the diffusion of species through the photonic crystal. This achievement is based on the use of a…
The formation of silver hydrogen trititanate nanotubes, based on the controllable microwave-assisted hydrothermal nanocrystalline TiO2 transition, was investigated by means of XRD, UV–vis–DRS, Raman, FESEM and HRTEM. The results show that the rapid formation of H-trititanate nanotubes is achieved by self-assemblage of silver nanoparticles in which the lamellar intermediates react with NaOH in hydrothermal conditions.…
Amorphous silicon oxynitride coatings with similar composition and different closed porosity were prepared by magnetron sputtering. Pores size, shape and distribution were evaluated by scanning electron microscopy and transmission electron microscopy. Raman and EELS analysis proved that the pores are filled with molecular nitrogen trapped during deposition. The mechanical properties evaluated by nanoindentation shows that…
Four different mono and bimetallic Ni–Co/ZrO2 catalysts have been studied by means of in situ XAS, X-ray diffraction, TPR, and measurements of the catalytic activity in the dry reforming reaction of methane (DRM). Even though the cobalt monometallic system has no activity for the methane reforming reaction, both bimetallic catalysts (with 1:1 and 1:2 Ni/Co…
The compressive strength of SiC-fiber bonded ceramics obtained from hot-pressed amorphous Si-Al-C-O fibers and its degradation by high temperature exposure to an oxidizing environment was studied. Compressive strength was measured at room temperature as a function of strain rate, orientation, and oxidation temperature. Weight loss was monitored as a function of exposure time in atmospheric…
Mesoporous tetragonal RE:YPO 4 nanophosphors (RE = Eu, Ce, Tb, and Ce + Tb) with a lenticular morphology, narrow size distribution, and high surface area have been prepared by an homogeneous precipitation procedure consisting of aging, at low temperature (80-120 °C) in a microwave oven, ethylene glycol solutions containing only yttrium acetylacetonate and phosphoric acid.…
TiO 2 nanoparticles have been prepared by sol-gel precipitation and further hydrothermal treatment. In this way, the effect of the hydrothermal treatment on the structural properties and photocatalytic activity of sol-gel synthesized catalysts has been investigated. These catalysts have been produced by hydrolysis of a mixture of isopropanol-titanium tetraisopropoxide (iPrOH-TiiP). The prepared photocatalysts were characterized…
Aluminum incorporation into the high pressure polymorph of TiO2 with the structure of alpha-PbO2 has been studied from 10 to 20 GPa and 1300 degrees C by XRD, high-resolution Al-27 MAS-NMR and TEM. Al-doped alpha-PbO2 type TiO2 can be recovered at atmospheric pressure. Al2O3 solubility in alpha-PbO2 type TiO2 increases with increasing the synthesis pressure.…