Analysis of the effect of cryolite on the reaction and combustion process of the mAl/pCuO thermites

• Published in: Combustion and flame 2023-01, Vol.247, p.112460, Article 112460
• Main Authors: Xu, Jianyong, Shi, Wei, Wang, Xiwen, Gu, Bonan, Yu, Chunpei, Majeed, Muhammad Amjad, Song, Changkun, Chen, Junhong, Yang, Gaopeng, Zhang, Wenchao
• Format: Article
• Language: English
• Subjects: Combustion performance; Cryolite; Interface contact; Reaction efficiency; Thermite
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/j.combustflame.2022.112460

Considerable attention has been attracted to thermites due to their high energy density and adjustable burning rate. Compared with nanothermites, micron thermites feature relatively low reaction efficiency due to little interface contact area between reaction components. It is still very necessary to investigate such thermites in which micron Al (mAl) functions as fuel, on account of their low cost and excellent storage stability. Herein, mAl and porous-sheet CuO (pCuO) function as fuel and oxidant, respectively. Different contents of Na3AlF6 are added for constructing mAl/pCuO/Na3AlF6 composites. Results of thermal analysis show that the addition of Na3AlF6 helps increasing the heat release of this thermite system among the temperature range of 25 °C -1000 °C. The existence of Na3AlF6 also improves the duration of combustion. It turns out that the thermite composites containing 10 wt% Na3AlF6 have the highest constant volume combustion pressure. Due to the reaction inertia of Na3AlF6, the burning rate of mAl/pCuO/Na3AlF6 is lower than the pristine mAl/pCuO. Characterization of the reaction products by mAl/pCuO and mAl/pCuO/Na3AlF6 at 1000 °C further illustrates that Na3AlF6 facilitates the reaction between the thermite components. These results indicate that Na3AlF6 shows great potential for improving the combustion efficiency of micron thermites.