湿度对纳米铝粉活性影响的研究

Effects of Humidity on Activity of Aluminum Nanoparticles

研究了存储环境湿度对纳米铝粉活性的影响,并对其变化机理进行了较深入的探讨。结果表明,环境湿度对纳米铝粉的活性影响十分明显:在相同存储时间内,随着环境湿度的增加,纳米铝粉的热焓和活性铝含量显著减少;原始纳米铝粉是被一层3nm厚非晶态氧化铝包覆的壳层结构,在不同湿度条件下放置8周后,壳层厚度将逐渐增加至5nm,随后不再继续增加。但在高湿度条件下,纳米铝粉颗粒芯部发现了类似壳层的非晶态结构,表明氧化行为仍在通过其它途径进入到了纳米铝粉的芯部。同时,在对纳米铝粉DSC-TG分析中还发现存在两次氧化现象。

A qualitative study on the effects of humidity on activity of aluminum nanoparticles has been reported in this letter. The Al nanoparticles were synthesized by the process of hybrid induction and laser heating （HILH）. In order to understand the stability of the oxide coating from aluminum nanoparticles, the Al nanoparticles were examined using high-resolution transmission electron microscopy （HRTEM） and the thermal behaviors were identified by DSC-TG. It was found that a compact amorphous oxide layer of 3 nm in thickness covered the original Al nanoparticles. After stored for 8 weeks, the oxide layer grew up to 5 nm in thickness, and the oxidation diffused to the interior of Al nanoparticles. The results indicate that the activity of Al nanoparticles is deeply influenced by the environment, especial the humidity. A higher relative humidity would accelerate the aging of Al nanoparticles. The DSC-TG results show that the oxidation of Al nanoparticles occurs at least in two steps.