Showing papers on "Chromium(III) oxide published in 2008"
TL;DR: In this article, a self-limited growth with a rate of 0.05-0.1nm/cycle was obtained at substrate temperatures of 330-420°C, and epitaxial eskolaite was formed on α-Al2O3( 1 1 ¯ 0 2 ) substrates.
31 citations
TL;DR: The first attempt to control the combustion and the detonation properties of a high explosive through its structure is reported, and it is demonstrated that the Cr(2)O(3) matrix encloses and stabilizes RDX particles at the nanoscale.
Abstract: This paper reports the first attempt to control the combustion and the detonation properties of a high explosive through its structure. A porous chromium(III) oxide matrix produced by the combustion of ammonium dichromate was infiltrated by hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The structure of the Cr(2)O(3) matrix was studied by both scanning and transmission electron microscopy (SEM, TEM); the Cr(2)O(3)/RDX nanocomposites were characterized by nitrogen adsorption. A mathematical model based on these techniques was used to demonstrate that the Cr(2)O(3) matrix encloses and stabilizes RDX particles at the nanoscale. The decomposition process of the nanocomposites was investigated by atomic force microscopy (AFM). The reactivity and sensitivity of the nanocomposites were studied by impact and friction tests, differential scanning calorimetry (DSC), time-resolved cinematography and detonation experiments, and were correlated with their structure. The size of RDX nanoparticles and their distribution in the Cr(2)O(3) matrix have an important influence on their reactivity. The reactive properties of nanostructured RDX differ significantly from those of classical micron-sized RDX. For instance, the melting point disappears and the decomposition temperature is significantly lowered. The quantization of the explosive particles in the Cr(2)O(3) matrix decreases the sensitivity to mechanical stress and allows controlling the decomposition mode-i.e. combustion versus detonation.
25 citations
TL;DR: In this paper, the acceleration of the conversion of δ-and θ-Al2O3 to α-Al 2O3 upon introduction of additives in the stage of synthesis of aluminum oxide was examined.
Abstract: Formation of α-Al2O3 in thermal treatment of ultradispersed aluminum oxide powders produced by shock-wave synthesis with addition of Cr2O3-(NH4)2Cr2O7 as a precursor was studied. The acceleration of the conversion of δ-and θ-Al2O3 to α-Al2O3 upon introduction of additives in the stage of synthesis of aluminum oxide was examined.