Abstract
Fabrication of FeSi-Al2O3 composites with a molar ratio of FeSi/Al2O3 ranging from 1.2 to 4.5 was conducted by the self-propagating high-temperature synthesis (SHS) method. The synthesis reaction involved metallothermic reduction of Fe2O3 and SiO2 by Al and the chemical interaction of Fe and Si. Two combustion systems were examined: one contained thermite reagents of 0.6Fe2O3 + 0.6SiO2 + 2Al, and the other had Fe2O3 + 2Al to mix with different amounts of Fe and Si powders. A thermodynamic analysis indicated that metallothermic reduction of oxide precursors was sufficiently exothermic to sustain the combustion reaction in a self-propagating mode. The SHS reaction carrying out co-reduction of Fe2O3 and SiO2 was less exothermic, and was applied to synthesize products with FeSi/Al2O3 = 1.2–2.5, while the reaction reducing only Fe2O3 was more energetic and was adopted for the composites with FeSi/Al2O3 = 2.5–4.5. Moreover, the former had a larger activation energy, i.e., Ea = 215.3 kJ/mol, than the latter, i.e., Ea = 180.4 kJ/mol. For both reaction systems, the combustion wave velocity and temperature decreased with increasing FeSi content. Formation of FeSi-Al2O3 in situ composites with different amounts of FeSi was achieved. Additionally, a trivial amount of aluminum silicate was detected in the products of high FeSi contents due to dissolution of Si into Al2O3 during the SHS process.
Funder
Ministry of Science and Technology, Taiwan
Subject
General Materials Science,Metals and Alloys
Cited by
7 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献