CO_(2) conversion and decarburization kinetics of CO_(2) gas and liquid Fe-C alloy at 1873 K

The reactions between CO_(2) gas and liquid Fe-C alloy with different initial carbon concentrations at 1873 K were investigated using experimental results,thermodynamic equilibrium,and kinetic analysis.The average CO_(2) conversion is greater than 80%when the carbon content ranges from 4.0 to 1.0 wt.%.When the carbon content decreases from 0.5 to 0.1 wt.%,the average CO_(2) conversion diminishes from 83.50%to 40.84%.This proves that CO_(2) gas and liquid Fe-C alloy reaction does not reach equilibrium under experimental conditions compared with the calculated thermodynamic data.Through the kinetic analysis,it is shown that in the medium-to high-carbon liquid Fe-C alloys,the rate-controlling step involves CO_(2) gas mass transfer or mixed rate-controlling of CO_(2) gas mass transfer with adsorption and dissociation of CO_(2) gas.In contrast,in the low-carbon liquid Fe-C alloy,carbon mass transfer occurs in the molten alloy.The critical carbon content of the rate-controlling step transformation is 0.7937 wt.%.

ELECTRICAL PROPERTIES OF CONDUCTIVE POLYMER COMPOSITES PREPARED BY AN INNOVATIONAL METHOD

An innovational method that poly(styrene-co-maleic anhydride)(SMA),a compatibilizer of immiscible nylon6/polystyrene(PA6/PS) blends,was first reacted with carbon black(CB) and then blended with PA6/PS,has been employed to prepare the PA6/PS/(SMA-CB) composites of which CB localized at the interface.In PA6/PS/CB blends,CB was found to preferentially localize in the PA6 phase.However,in the PA6/PS/(SMA-CB) blends,it was found that CB particles can be induced by SMA to localize at the interface.The electrical porperties of PA6/PS/(SMA-CB) composites were investigated.The results showed that the composites exhibited distinct triple percolation behavior,i.e.the percolation is governed by the percolation of CB in SMA phase,the continuity of SMA-CB at the interface and the continuity of PA6/PS interface.The percolation threshold of PA6/PS/(SMA-CB) was only 0.15 wt%,which is much lower than that of PA6/PS/CB.Moreover,the PTC(positive temperature coefficient) intensity of PA6/PS/(SMA-CB) composites was stronger than that of PA6/PS/CB and the negative temperature coefficient(NTC) effect was eliminated.The electrical properties of PA6/PS/(SMA-CB) were explained in terms of its special interface morphology:SMA and CB localize at interphase to form the conductive pathways.