Chemical Engineering Journal, Vol.162, No.3, 1075-1081, 2010
Combined effect of thermal and mechanical activation on the combustion and phase formation laws in the Cr-Si-C system
In this work combustion and phase formation laws for mechanically and thermally activated Cr-Si-C system were studied. For thermal stimulation in the combustion reaction Mg-(-C2F4-) high caloric mixture was used. It was shown that in the system understudy, combustion takes place by two sequential stages. The first stage is interaction between Si and (C2F4-) or Mg with (C2F4-) (temperature can rise up to 1200 degrees C), which are responsible for combustion front propagation. In the first stage, formation of small amount of CrSi2 takes place. The second stage is Si + C reaction which is responsible for high-temperature combustion. In the second stage, formation of CrSi2 completes. The influence of mechanical treatment on combustion laws for (Cr-Si) + (Si-C)+(Mg-(C2F4)) system was investigated. It was shown that mechanical activation (MA) is effective for systems where amount of chromium is high, while for systems where Si-C part is appreciable MA does not have any affect. (C) 2010 Elsevier B.V. All rights reserved.
Keywords:Activated combustion synthesis;Self-propagating high-temperature synthesis (SHS);Mechanical activation;Differential thermal analysis (DTA);Scanning electron microscopy (SEM);Composite