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硼具有比镁、铝更高的能量密度,是一种具有很大应用潜力的理想固体添加剂。但硼颗粒着火过程机理尚不明确,尤其是着火过程中关键阶段:氧化层增厚的过程,更需要深入研究。本文利用热重和管式炉等实验方法,对微米硼颗粒着火阶段的氧化膜增厚过程,即氧化性能进行了研究。发现在氧气/氮气或空气的气氛中,微米硼颗粒的氧化过程分为脱水、快速氧化和慢速氧化三个阶段。利用多个升温速度法求得快速氧化阶段的活化能为131.74 kJ/mol。微米硼颗粒的着火温度约为929~969 K。着火温度随着加热速度的增加而升高,随着氧气浓度的增加而降低。硼颗粒氧化后会黏结在一起,形成类似“切糕”状产物:未氧化的单质硼镶嵌在氧化产物B_2O_2及B_2O_3中。这种产物结构说明了(BO)n扩散模型具有合理性。
Boron has a higher energy density than magnesium and aluminum and is an ideal solid additive with great potential for application. However, the mechanism of the ignition process of boron particles is not clear, especially the key stage in the ignition process: the thickening process of oxide layer needs further study. In this paper, using the experimental methods such as thermogravimetry and tube furnace, the oxidation process of the oxide film during the ignition phase of the micron boron particles is studied. It is found that in the atmosphere of oxygen / nitrogen or air, the oxidation process of micron boron particles is divided into three stages of dehydration, rapid oxidation and slow oxidation. The activation energy of the rapid oxidation stage was found to be 131.74 kJ / mol using multiple heating rates. The ignition temperature of micron boron particles is about 929-969 K. The ignition temperature increases with the heating rate, and decreases with the oxygen concentration. After the oxidation of boron particles will be bonded together to form a similar “cut cake” -like products: unoxidized elemental boron embedded in the oxidation products B_2O_2 and B_2O_3. This product structure illustrates the (BO) n diffusion model is reasonable.