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<p>The properties of oxidants significantly affect the thermal and combustion properties of nanothermites, and alpha and beta-MnO<sub>2</sub> nanorods with similar morphological appearances were prepared using the hydrothermal method. Corresponding nanothermites were prepared employing the electrostatic spraying method and their thermal and combustion properties have been compared through TG-DSC and combustion tests. The aluminothermic reaction process was simulated by molecular dynamics, and the results showed that the β-MnO<sub>2</sub>/Al nanothermite first underwent β-MnO<sub>2</sub> thermal decomposition followed immediately by an aluminothermic reaction, whereas the α-MnO<sub>2</sub>/Al nanothermite underwent a direct aluminothermic reaction. In contrast, the α-MnO<sub>2</sub>/Al nanothermite could release more heat. According to thermal analysis, the activation energy of α-MnO<sub>2</sub>/Al nanothermite was 100.15&#xa0;kJ&#xa0;mol<sup>− 1</sup> higher than β-MnO<sub>2</sub>/Al nanothermite, indicating better stability. Combustion experiments showed that the combustion propagation rate of the α-MnO<sub>2</sub>/Al nanothermite was faster than the β-MnO<sub>2</sub>/Al nanothermite. The results have been verified and the reaction process has been exhibited using molecular dynamics to simulate the aluminothermic reaction process. The notable differences in the thermal and combustion properties of nanothermites containing MnO<sub>2</sub> with varying phases can be attributed to the distinct crystal structures of α-MnO<sub>2</sub> and β-MnO<sub>2</sub>. The alternating 1 × 1 and 2 × 2 tunnel structure of α-MnO<sub>2</sub> is more stable, whereas β-MnO<sub>2</sub> undergoes thermal decomposition before the aluminothermic reaction.</p>

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Effect of Crystal Phase on the Thermal and Combustion Properties of MnO2/Al Nanothermites

  • 期刊论文

  • 发表日期：

    2025年3月11日

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  • Jialin Chen,
  • Ming An,
  • Mengnan Dai,
  • Shutao Li,
  • Yeqing Chen,
  • Rui Song,
  • Jiaxing Song,
  • Longming Chen,
  • Xiting Zhong,
  • Quanwei Tian

摘要

The properties of oxidants significantly affect the thermal and combustion properties of nanothermites, and alpha and beta-MnO2 nanorods with similar morphological appearances were prepared using the hydrothermal method. Corresponding nanothermites were prepared employing the electrostatic spraying method and their thermal and combustion properties have been compared through TG-DSC and combustion tests. The aluminothermic reaction process was simulated by molecular dynamics, and the results showed that the β-MnO2/Al nanothermite first underwent β-MnO2 thermal decomposition followed immediately by an aluminothermic reaction, whereas the α-MnO2/Al nanothermite underwent a direct aluminothermic reaction. In contrast, the α-MnO2/Al nanothermite could release more heat. According to thermal analysis, the activation energy of α-MnO2/Al nanothermite was 100.15 kJ mol− 1 higher than β-MnO2/Al nanothermite, indicating better stability. Combustion experiments showed that the combustion propagation rate of the α-MnO2/Al nanothermite was faster than the β-MnO2/Al nanothermite. The results have been verified and the reaction process has been exhibited using molecular dynamics to simulate the aluminothermic reaction process. The notable differences in the thermal and combustion properties of nanothermites containing MnO2 with varying phases can be attributed to the distinct crystal structures of α-MnO2 and β-MnO2. The alternating 1 × 1 and 2 × 2 tunnel structure of α-MnO2 is more stable, whereas β-MnO2 undergoes thermal decomposition before the aluminothermic reaction.