硼粉热特性研究

为了研究硼粒子在不同气氛下热特性,采用TGA/DSC和高压DSC对晶体硼粉和无定形硼粉两种形态,在纯氮、纯氧、空气以及氧氮混合(1∶1)气氛和3种压强下进行热分析实验;利用Kissinger法和Ozawa法计算得到无定形硼在空气气氛下的动力学参数.试验结果表明,纯氮气氛下,无定形硼与氮气会发生反应,其反应速度缓慢,放热量小.无定形硼比晶体硼的氧化反应初始温度低,氧化反应更快且更完全.不同氧气浓度条件下,随着氧气浓度的提高,无定形硼反应起始温度提前,反应速率加快,反应更彻底.增加氧气压强,可降低初始反应温度,加快反应速率,提高反应放热量.最终计算得到无定形硼在空气气氛下的活化能E、指前因子A和反应速率常数K.

Thermal-characteristic research of boron

In order to investigate the thermal-characters of boron in different ambiences, the thermal-analysis experiments of crystal boron and amorphous boron were carried out using TGA/DSC and high pressure DSC in pure pressures. The kinetic parameters of amorphous boron in air were calculated using Kissinger and Ozawa method. The results show that amorphous boron can react with N_2 under ambient pressure with slow reaction rate and less releasing heat. Comparing to the crystal boron, the initial reaction temperature of the amorphous boron was much lower and oxidation reaction was much faster and complete. With the increase of oxygen concentration, the reaction becomes easier and faster. Corresponding to the pressure variation of pure oxygen, initial reaction temperature and peak temperature are changed as well as the heat of reactions. The activation energy(E), pre-exponential factor(A) and reaction rate constant(K) of amorphous boron in air can be obtained.