纳米结晶体Ni_(0.5)Zn_(0.5)Fe_2O_4对高氯酸铵热行为及分解反应动力学的影响(英文)

Effect of Nanocrystal Ni_(0.5)Zn_(0.5)Fe_2O_4 on Thermal Behavior and Decomposition Reaction Kinetics of Ammonium Perchlorate

采用差示扫描量热法(DSC)、热重和微分热重(TG-DTG)及固相原位反应池/快速扫描傅立叶变换红外联用技术(hyphenatedinsituthermolysis/RSFTIR)研究了纳米结晶体Ni0.5Zn0.5Fe2O4与高氯酸铵(AP)组成的混合物的热行为和分解反应动力学。结果表明:Ni0.5Zn0.5Fe2O4使得AP的低、高温分解放热峰温分别提前17.44K和27.74K,并使得对应的分解热分别增加3.7J·g-1和193.7J·g-1。Ni0.5Zn0.5Fe2O4并不影响AP的晶转温度和晶转热。Ni0.5Zn0.5Fe2O4使得AP的TG曲线出现3个阶段,并使得后2个失重阶段的初始和终止温度都有所提前。凝聚相分解产物分析表明Ni0.5Zn0.5Fe2O4加速了凝聚相AP的分解及氨气的释放。含Ni0.5Zn0.5Fe2O4的AP的高温分解反应的动力学参数Ea=238.88kJ·mol-1,A=1018.59s-1,动力学方程可表示为dα/dt=1018.99(1-α)[-ln(1-α)]3/5e-2.87×104T。始点温度(Te)和峰顶温度(Tp)计算得出AP的热爆炸临界温度值分别为:574.83K和595.41K。分解反应的活化熵(ΔS≠)、活化焓(ΔH≠)和活化能(ΔG≠)分别为:109.61J·mol-1·K-1、236.49kJ·mol-1及172.58kJ·mol-1。

The thermal behavior and non-isothermal decomposition reaction kinetics of the mixture of the nanocrystal Ni0.5Zn0.5Fe2O4 and ammonium perchlorate （AP） were investigated by differential scanning calorimetry （DSC）, thermogravimetry and differential thermogravimetry （TG-DTG）, and the hyphenated technique of in situ thermolysis cell with rapid-scan Fourier transform infrared spectroscopy （in situ thermolysis/RSFTIR）. The results show that Ni0.5Zn0.5Fe2O4 can decrease the low-temperature and the high-temperature exothermic peak temperatures of AP by 17.44 K and 27.74 K, respectively, and increase the decomposition heats of the two exothermic peaks by 3.7 J·g^-1 and 193.7J·g^-1, respectively. Ni0.5Zn0.5Fe2O4 does not affect the crystal transformation temperature and heat of AP. Ni0.5Zn0.5Fe2O4 makes AP shown three mass-loss processes, and it can decrease the initial and terminated temperatures of the last two mass-loss stages. The condensed phase decomposition product analysis shows that Ni0.5Zn0.5Fe2O4 accelerates the decomposition of condensed AP and the release of the gaseous NH3. The kinetic parameters Ea=238.88 kJ·mol^-1, A =10^18.59s^-1, and the kinetic equation of the high-temperature decomposition reaction of Ni0.5Zn0.5Fe2O4/AP can be described as： dα/dt=10^18.59 （1-α）[-ln （1-α）]^3/5 e^-2.87×10^4T. The corresponding critical temperatures of thermal explosion （Tbe and Tbp） corresponding toβ→0 are 574.83 K and 595.41 K, respectively. The entropy of activation （ΔS^≠）, enthalpy of activation （ΔH^≠）, and free energy of activation （ΔG^≠） of the decomposition reaction are 109.61J·mol^-1·K^-1, 236.49 kJ·mol^-1, and 172.58 kJ·mol^-1, respectively.