Effect of Mechanical Activation on the Kinetics of Silica Carbothermal Reduction in non-Isothermal Conditions

The effect of mechanical activation on the synthesis temperature decreasing of silicon carbide was investigated and a kinetic model of a carbothermic reduction of silicon carbide was obtained. Silicon carbide was synthesized using silica activated in a planetary mill at different times up to 40 h under an argon atmosphere. Structural changes due to the milling and the reduction of the activated silica were studied by the X-Ray diffraction (XRD) method and non-isothermal TGA with a heating rate of 10^∘C min⁻¹ respectively. The kinetic model obtained by the fitting technique for an unmilled sample was found to be chemically controlled of the second order with E = 138.92 Kcal.mol⁻¹ and A =3.92×10¹⁵ s⁻¹. For the sample milled up to 20 h, according to the Avrami-Erofeev3 equation; A = 1465633 s⁻¹ and E = 66.71 Kcal.mol⁻¹.