Study On Thermodynamics And Kinetics Mechanism For Zr-Al-C Systerm

In this paper, we focus on thermodynamic and kineties analysis. There are many excellent compounds in the system.They combine the excellent performances of ceramics and metal. So they are expected to be high-temperature structural materials. But this system involves so many binary compounds, ternary compounds and the formation mechanism of Zr-Al-C compounds is complex. For learing formation mechanism of Zr-Al-C compounds better, ptimizing experimental program, we focus on calculating thermodynamic data, analyzing kinetic process and designing Experiment.In this pape, we collect and analyze comprehensive the data of binary compounds.Then, we can get the order of stability, formative priority and estimate thermodynamic data of Zr2Al3C5, Zr3Al3C5. At last, we can identify the possibility of chemical reactions.We use non-pressure synthesis method and mixed Zr, Al, C powers which heated by different rato5K/min,10K/min,15K/min. At last, we foucus on the kinds and the amounts of products.Then, we analyse the results by Matlab software. In this process, pharmacokinetic parameters were calculated by peak temperatures. We obtain the relationship between the conversion rate and time by Matlab; At last, we apply the mechanism function model to analyse the process.The results of thermodynamic calculations show that ZrC and Al4C3are the most stable compounds, ZrAl3is the first emerged compound in the system. Zr3Al3C3is more easily to product than Zr2Al3C3at low temperatures, but it is lack of motivation at the high temperatures.Non-pressure synthesis experimental results show that more slowe, more fully in the reaction. We can conclude that, from the room temperature to1250℃, the process:At first, Zr and Al occurred weak solid-phase reaction; Then, Al begin to melt; Al and Zr occurred strong chemical reactions and Zr-Al compounds are emerged; Then Zr-Al compunds began to contact with C powers and formed ternary compound Zr3Al3C5slowly; At last, Zr2Al3C5is formed when the temperature is above1200℃.Kinetic analysis shows that Zr-C and Al-C binary system are all weak respond to the temperature. In the Zr-Al binary system and Zr-Al-C ternary system, nucleation process of ZrAl3control reaction rate. In the Zr-Al-C ternary system, the temperature of the reaction concentrated in630and1000degree. Above1000℃ the system mainly occours Zr-Al(s)+C(s)â†'-Zr-Al-C(s). On the condition of slow heating, the process can be described the following procedure:Avrami nucleationâ†'-mixed-controlled reaction. On the condition of slow heating, the process can be described the following procedure:saturated position nucleation.