纳米铝粉热反应特性的TG-DSC研究

Investigation on nano-aluminum thermal reactivity by TG-DSC

采用TG-DSC法对平均粒径85 nm的纳米铝粉进行了热反应特性研究,并与微米铝粉进行了对比。结果表明,铝粉热反应特性的尺度效应明显,纳米铝粉在517℃附近出现明显增重,500～660℃氧化增重20.4%,放热约4 909 J/g,而微米铝粉在600℃左右才有少量的增重,粒径越大,氧化增重越小,4～6、9～10、16～20μm对应的氧化增重分别为2.02%、1.03%、0.89%;升温速率对纳米铝粉初始氧化阶段的氧化增重影响不大,Δm=22.8%～24.7%,初始氧化反应热为(4 850±350)J/g;但对纳米铝粉氧化速率的影响显著,随着升温速率的加快,初始氧化区间明显变窄,初始氧化速率明显加快,DSC初始氧化峰所对应的起始反应温度和峰值温度差(Tp-Ton)从5 K/min的40 K和10 K/min的33 K缩短为15K/min的2.2 K和20 K/min的4.3 K,最大氧化速率vox从5 K/min的0.019 mg/s增加为20 K/min的0.55 mg/s。

The thermal reactivity of 85 nm-Al was characterized by TG-DSC,and was compared to the reactivity of micron-Al powders.The results show that the thermal reactivity of aluminum has obvious size effect.Nano-Al gain weight quickly at about 517℃,and ranging from 500 ℃ to 660 ℃,the mass increase about 20.4%,with releasing heat of about 4 909 J/g.While micron-Al only gain weight a little at about 600℃.And the larger the particle size was,the less the weight increased.The aluminum particle of 4~6,9~10 and 16~20 μm gain weight 2.02%、1.03%、0.89% respectively.In addition,the heating rate has little influence on nano-aluminum＇s weight gain before the melting point.The weight increase about 22.8%~24.7% at the four heating rates,releasing heat（4850±350）J/g.However,the heating rate affects oxidation rate much more.With the increase of the heating rate,the initial oxidation temperature range shrinks sharply and the oxidation rate increases notably.The temperature range between the initial oxidation temperature and the peak temperature from DSC（Tp-Ton）changes from 40 K to 2 K,and the maximum oxidation rate vox varies from 0.019 mg/s to 0.55 mg/s.