The Mathematics Model And Behavior Of Combustion Synthesis Under Electric Field

The synthesis of materials with particular structure and performance promote the materials science to develop. The exploitation of new materials rests with the new synthesis technology. At the present time, there are some researches about the synthesis of iron-based composites by combustion synthesis at high temperature. A recently developed method, referred to in the literature as filed-activated combustion synthesis has been successfully developed as a new combustion synthesis technology. In this paper, the samples are heated up by great current, and the electric field is used not only to activate and maintain but also to control the combustion synthesis process. The work is carried out in detail as follows:(1) By using the Gleeble-1500D thermal instrument, the Fe-Ti-C/Fe-V-C/W-C-Co system's temperature rise character is investigated under electric current in low temperature. The temperature rise character curve indicates that there are four stages during the combustion synthesis of systems.(2) The product's phase and morphology of the combustion synthesis is identified by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the three systems have reacted under the present temperature rise rate and with the temperature rise rate increase the grains become smaller for the same system.(3) In the experiment, the Fe-Ti-C/Fe-V-C/W-C-Co is used to represent high/moderate/low thermal system. The system's combustion synthesis characters(ignition time, ignition temperature .etc) are investigated under the same temperature rise rate for the different system and the different temperature rise rate for the same system. The outcome shows that with the temperature rise rate increase the ignition time become shorter and ignition temperature become smaller to the same system. For different system with the same temperature rise rate, the ignition time become longer and ignition temperature become higher with the transition of high thermal system to low thermal system.(4) Based on experiment and energy conservation law, the mathematics model of the combustion synthesis is set up. From the model, the variation of the reaction ratio with time and the finally reaction ratio can obtained. The influence of temperature rise rate for the same system and thermal for different system with the same temperature rise rate is investigated. The results show that the finally reaction ratio increase with temperature rise rate increase for the same system and thermal discharge for different system.(5) Some research about the mechanism based on Ginsterlinger equation has been carried out. The combustion synthesis of Fe-Ti-C/Fe-V-C/W-C-Co consistent with Ginsterlinger equation and this means the combustion react under solid phase. To the same system, with the temperature rise rate increase, K_k become larger. For high, moderate, low discharge heat system with the same temperature rise rate, K_k become smaller with the transition of high thermal discharge to low discharge system.