Study on the preparation and combustion performance of AlF composites prepared by a solvent/non-solvent method

Oxidants, such as oxygen, cannot easily approach the core Al due to the presence of dense alumina on the surface of aluminum particles, thereby resulting in high ignition temperature and long ignition duration. To overcome this challenge, we employed the solvent/non-solvent method using Viton A (a copolymer of 1,1-difluoroethylene and hexafluoropropylene) as a coating material to prepare the core-shell Al/Viton A composite particles. An orthogonal experiment was designed to identify the optimal preparation parameters by evaluating the peak pressure in a closed vessel. The sample with the largest peak pressure was compared with raw Al and Al/Viton A (prepared by the physical mixing method) using the combustion pressure and open combustion tests to evaluate the solvent/non-solvent method. The results from the orthogonal experiment revealed that the water bath temperature exhibited the greatest influence on the coating effects. The composite prepared under a water bath temperature of 55 °C and a stirring rate of 250 rpm, using 20 mL of acetone and a 5 mL/min dripping rate of the Viton A acetone solution, were uniformly coated by Viton A, and exhibited excellent combustion characteristics. In addition, the sample generated using the optimal preparation parameters burnt more vigorously and rapidly than raw Al and Al/Viton A. Finally, the reaction molecular dynamics simulation was employed to gain insight into the effect of Viton A on the combustion of Aluminum particles at the molecular level.