The main features of high temperature chemical reactions under microwave (MW) heating have been considered. The efficiency of the MW power to heat conversion in a MW cavity is estimated, theoretically and experimentally, for different substances and conditions. The new approaches for MW processing of high-molecular hydrocarbons are proposed: (i) thermal decomposition in contact with microwave absorbing catalyst particles placed into liquid substrate; (ii) cracking of hydrocarbons pre-absorbed inside porous granules under rapid MW heating of adsorbent. It has been experimentally found that these approaches provide non-traditional conditions of reaction and can lead to the formation of valuable chemical products.
The evaporation of high purity silicon ingot was performed in Ar, N 2 , and air atmospheres using a power electron accelerator. The obtained powders with primary particle sizes of 10 -500 nm were investigated using Brunauer-Emmett-Teller analysis (BET), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence measurement, and Raman spectroscopy. The structure and photoluminescence properties of Si(Ar) nanopowder obtained at a large quenching rate differ substantially from those of Si(Ar) and Si(N 2 ) obtained at a smaller quenching rate. Photoluminescence peaks in the visible region of the spectrum are detected at room temperature for the Si(Ar) nanopowders.
Porous ceramometal Al2O3/CoAlO/CoAl was studied by set of physicochemical techniques such as XRD, SEM, internal field59Co and27Al MAS NMR, and porosity measurements. They revealed the cermet containing three parts. First, cobalt-free large porous alumina particles which surrounded by the second oxide part representing spinel CoxAl3-xO4(x=1,2,3) oxides. And third, oxygen-free metallic part consists of cobalt metal particles covered by Co-Al oxide protecting the metallic part from oxidation. Porosity measurements ascertained high porosity (60%) and good SSA (122 m2/g). Also the enhanced adsorption of microwaves due to metallic particles randomly distributed in oxides was found.
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