氧烛中锰金属粒径对氯酸钠热解的催化作用

分别制备了两组粒径的Mn金属燃料(平均粒径分别为18.73和5.24μm),利用激光粒度分析仪测试了其粒径分布,扫描电镜分析了表面形貌,能谱仪确定了所含元素.对NaClO3,NaClO3与Co3 O4,NaClO3、Co3 O4与Mn的混合物分别进行了热重与示差扫描量热联合分析实验(TGA-DSC),通过对比各混合物热解起始温度及其他特征温度,探究了Mn金属粒径对NaClO3热解的催化强度与热解稳定性的影响.研究结果表明:Co3 O4虽对NaClO3热解具有催化性,热解开始温度(To)由512.3℃ 下降为333.0℃,但其可导致NaClO3热解的不稳定,热解阶梯由1个变为3个;Mn金属燃料对NaClO3中间产物具有明显的催化性,且随着粒径减小,催化强度逐渐增加,热解终止温度(Tf)由419.8℃ 下降为351.9℃,同时NaClO3热解阶梯减少,热解温度区间变窄(由180.6℃ 减小为19.4℃),热解更加稳定.

Catalytic effect of Mn particle size on thermal decomposition of sodium chlorate in oxygen generators

Two groups of Mn metal fuels with different particle-size distributions were prepared with median diameters of 18. 73 and 5. 24 μm. The particle-size distribution was measured by a laser particle-size analyzer, the surface morphology was analyzed via scanning electron microscopy (SEM), and energy dispersive spectrometry (EDS) determined the contained elements. For the Na-ClO3 , the NaClO3 and Co3 O4 as well as NaClO3 , Co3 O4 , and Mn mixtures were subjected to TGA- DSC combined thermogravimetric analysis. The effects of the Mn metal fuel particle size on the catalytic effect and pyrolysis stability of NaClO3 were investigated by comparing the pyrolysis onset/ final temperature and other characteristics. The results show that although Co3 O4 has a significant cata-lytic effect on the pyrolysis of NaClO3 , e. g. , the onset pyrolysis temperature decreases from 512. 3 to 333. 0 ℃ , it can lead to insta-bility in NaClO3 pyrolysis, namely the pyrolysis steps from 1 to 3. The Mn metal fuel has a clear catalysis effect on the intermediate products of NaClO3 pyrolysis. With the decrease in particle size, the catalytic effect gradually increases and the pyrolysis final temper-ature Tf decreases from 419. 8 to 351. 9 ℃ . Meanwhile, the pyrolysis step of NaClO3 decreases and the temperature range of pyrolysis decreases from 180. 6 to 19. 4 ℃ , indicating that the pyrolysis process becomes more stable.