核壳结构Ni(Cu,Co)/Al微纳米复合粒子的制备及其与Fe_2O_3的热反应性能表征

Preparation of Core-Shell Ni (Cu, Co)/Al Micron-Nano Composites and Characteristics of Thermite Reactions with Fe_2O_3

采用置换法通过对溶液中各种参数的控制,实现了在弱酸性条件下Ni(Cu,Co)3种纳米金属粒子在微米Al粉表面定量、快速地化学沉积,分别制备出核壳结构的Ni(Cu,Co)/Al3种微纳米复合粒子,并用SEM和XRD方法进行了相应表征。在此基础上,利用DSC分析研究了不同包覆物和升温速率对热反应性能的影响,用Kissinger法求解了热反应的表观活化能Ea,对比了传统微米级Al-Fe2O3混合物与Ni(Cu,Co)/Al-Fe2O3复合材料的热反应性能,同时分别提出了其相应的热反应机制。结果表明,通过对Al粉进行表面改性,其热反应性能明显增强,不同试样与Fe2O3的热反应活性依次为Ni/Al>Cu/Al>Co/Al>Al。同时,降低升温速率不利于热反应的进行。

Three kinds of core-shell Ni（Cu,Co）/Al nano composites have been prepared via a novel and facile displacement method with Fe2O3 and characterized by SEM and XRD. The characteristics of thermite reactions are investigated by Kissinger method and differential scanning calorimetry （DSC） as a function of heating rates and compared with the micron-sized AI powders with Fe2O3. Several parameters have been used to characterize the performance of thermite reaction, including the heat released energy, the activation energy, onset and peak temperatures. Results indicate that the reactivity ofNi（Cu,Co）/Al nano composites with Fe2O3 is significantly higher than that of raw AI powders with the order of Ni/Al〉Cu/Al〉Co/Al〉Al, but depends strongly on the heating rate. The nano metal particles change the diffusion mechanism of oxygen and relax the negative effect of Al2O3 layer in the course of thermite reaction in a large degree. And the lower heating rate will be deleterious to the reactions.