核壳结构纳米铝粉热学行为

Thermal Behavior of Core-Shell Structure Aluminum Nanopowders

关键词:  含能材料  纳米铝粉  核壳结构  热学行为

Key words:  Energetic materials  Aluminum nanopowders  Core-shell structure  Thermal behavior

摘要:

为了研究不同表面包覆物对纳米铝粉热学行为的影响,采用激光-感应复合加热法制备了三种不同表面包覆的核/壳结构纳米铝粉(氧化铝钝化、碳包覆及增塑剂DOS包覆)。采用高分辨透射电镜(HRTEM)对制备的纳米粉末结构进行表征,并采用差示扫描量热及热重分析(DSC-TG)对不同物质包覆纳米铝粉的热学性能进行研究。结果表明,这些纳米粒子均呈现出明显的核壳结构,且包覆层厚度约3.5nm。这三种不同表面包覆纳米铝粉在400℃至铝熔点(660℃)之间均发生了氧化,但非氧化物包覆纳米铝粉(碳包覆与增塑剂DOS包覆)的氧化开始温度及峰温比氧化铝钝化纳米铝粉提前了约30℃左右,而且氧化放热热焓和氧化质量增重均高于氧化铝钝化纳米铝粉,表明这两种非氧化物表面包覆对纳米铝粉的热学行为有积极的影响。最后对不同物质包覆纳米铝粉的破壳氧化机制进行了探讨。

Abstract:

To discuss the effect of different surface coatings on the thermal behavior of Al nanopowders, three kinds of core-shell structure Al nanopowders with different surface coatings (Al₂O₃ passivation coating, carbon coating, and Plasticizer DOS coating) were prepared by laser-induction complex heating technology. The structure characterization of the as-prepared nanopowders was revealed using high resolution transmission electronic microscopy (HRTEM), and the thermal properties were investigated using differential scanning calorimeter (DSC) and thermal gravimeter (TG) analysis. The results show that these Al nanoparticles all show obvious core-shell structue, and the coating thickness is about 3.5 nm. The early oxidation of the three Al nanopowders with different surface coatings is observed between ~400 ℃ and the melting point of Al (~660 ℃). However, the onset temperature and the peak temperature for the oxidation of Al nanopowders with non-oxide protective coatings (carbon coating and Plasticizer DOS coating) are about 30 ℃ lower than those of Al₂O₃-passivated Al nanopowders, and the enthalpy change and the mass gain of them are higher than those of Al₂O₃-passivated Al nanopowders, which indicate that the two non-oxide surface coatings have a positive impact on the thermal behavior of Al nanopowders. The oxidation mechanism of broken shell of Al nanopowders with different surface coatings is discussed. 