(東北大學(xué) 材料與冶金學(xué)院, 沈陽 110004)
摘 要: 利用XRD、TG/DTA技術(shù)分別分析真空碳管爐內(nèi)不同反應(yīng)溫度下的物相組成和碳熱共還原Al2O3、SiO2的反應(yīng)過程，并在此基礎(chǔ)上探討碳熱還原法制取鋁硅合金的反應(yīng)機(jī)理。分別采用10、15、20和25 K/min升溫速率的差熱分析，研究動態(tài)氬氣氣氛中碳熱法制取鋁硅合金的反應(yīng)動力學(xué)。結(jié)果表明：碳熱還原反應(yīng)過程可分為4個階段，其中，以碳化物的生成與分解階段為主。碳熱還原反應(yīng)的4種還原機(jī)理中，碳化物的生成與分解理論能較好地解釋反應(yīng)過程中出現(xiàn)的反應(yīng)現(xiàn)象。各個吸熱峰的表觀活化能分別為848.9、945.4、569.7、325.7、431.9和723.1 kJ/mol，給出了各個吸熱峰的動力學(xué)方程。同時，利用XRF和紅外定硫定碳儀對碳管爐和電爐所得產(chǎn)物組成的定量分析，驗(yàn)證了動力學(xué)分析結(jié)果的可行性。
關(guān)鍵字: 碳熱還原；差熱分析；鋁硅合金；反應(yīng)機(jī)理；動力學(xué)方程
aluminium-silicon alloys by carbothermal reduction method
（School of Materials and Metallurgy, Northeastern University, Shenyang 110004, China）
Abstract:The composition of products obtained under different temperatures in vacuum graphite furnace was studied by XRD, and the reaction process of carbothermal reduction of Al2O3 and SiO2 was analysed by TG-DTA as well. Based on these, the reaction mechanism of carbothermal reduction method was discussed. The kinetics of preparation of Al-Si alloys by carbothermal reduction of Al2O3 and SiO2 was studied by means of differential temperature analysis (DTA) at different temperature rising rates of 10, 15, 20 and 25 K/min. The results show that the carbothermal reduction process can be divided into 4 stages, and the key stage is the formation and decomposition of carbides period. Among the 4 mechanisms of carbothermal reduction of Al2O3 and SiO2, the formation and decomposition of carbides theory may be the best one to interpret the reaction process. The apparent activation energy of each endothermic peak is obtained by Flynn-Wall-Ozawa and Kissinger methods as follows: 848.9, 945.4, 569.7, 325.7, 431.9 and 723.1 kJ/mol, and the kinetic equations are also determined. Meanwhile, the feasibility of the results of kinetics analysis is verified using the products obtained in vacuum graphite furnace and arc furnace by XRF and infrared absorption carbon-sulfur analysis unit.
Key words: carbothermal reduction；differential thermal analysis；aluminium-silicon alloy；reaction mechanism；kinetics equation
