摘要
分析并讨论CuO、Cu2O、MgO在自蔓延反应的低温和高热阶段的分级供氧及其热力学行为。研究表明在常温条件下CuO比Cu2O稳定,而在高温条件下则相反;另外,在低温时Mg比Al活泼,但在高温时Al可以从MgO中将Mg置换出来。因此,通过在铝热剂反应体系CuO+Al中添加MgO组分,在反应的初始阶段由CuO分解供氧,在反应的高温阶段由Cu2O和MgO分解供氧,形成不同温度下分级供氧的复合燃烧体系。在这种复合燃烧反应中,MgO分解吸收大量的热,吸收铝热反应产生的部分热量,削减了热峰,且在反应的降温阶段,Mg再次被氧化释放热量,实现自蔓延铝热剂发热量的控制策略。试验研究结果表明,铝热剂燃烧反应平稳,焊剂产热均匀且高热不爆,焊接成型美观且成型质量较好,该分级供氧复合燃烧体系对稳定自蔓延铝热反应过程具有显著效果。
The thermodynamic behavior of CuO, Cu20 and MgO was analyzed at the low-temperature or at the high-temperature in self-propagating reactions of thermit respectively. The results show that CuO was more stable than Cu20 at the normal temperature, but it was in the contrary at high temperature; in addition, at low temperature, magnesium was more active than aluminum, but at high temperature aluminum can replace magnesium from magnesium oxide. By adding MgO to CuO＋A1 thermite, oxygen was supplied by the decomposition of CuO in the initial phase of the reaction, however oxygen was supplied responsively by the decomposition of Cu20 and MgO in the high temperature phase, which formed a different oxygen-supplied and complex combustion system at different temperature. In this combustion system, MgO absorbed the heat at high temperature by reduction reaction and released the heat at lower temperature by oxidation reaction. The heat of thermal peak was cut and moved to the late reaction stage, so thermit heat was averaged in the whole combustion process and the controlling strategies about the heat released by thermit was realized. The experiment results show that this complex oxygen supplied system had a significant effect on the self-propagating thermite reaction. The thermite had an advantage of stable combustion, high heat without explosion, beautiful forming, and fewer defects and so on.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2012年第20期142-146,共5页
Journal of Mechanical Engineering
基金
国防科工委/教育部重点科研资助项目(208100036)
关键词
自蔓延
铝热焊剂
分级供氧
热量均衡
Self-propagating high-temperature synthesis Thermit Complex oxygen-supply Heat balance
