A new process is introduced for repair of structural components of aluminum alloys. Additive manufacturing, maintenance and repair welding, Al alloy, mechanical properties.

To improve the thermal properties of thermite safely and stably, electrostatic spraying was used to prepare the Al/MoO 3 thermite. The Al/MoO 3 thermites were detected and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and thermal decomposition experiments were carried out by differential scanning calorimetry (DSC). The heat release of the Al/MoO 3 thermite prepared by the electrostatic spray (1044 J g −1 ) is significantly higher than that of the thermite prepared by the ultrasonic (692 J g −1 ), which is due to more uniform dispersion between Al and MoO 3 . The initial reaction temperature and activation energy (E a ) of the former keep it steady. Electrostatic spray ensures the safety and stability of the Al/MoO 3 thermite. This study provides a new idea for safely and stably improving the thermal properties of thermite by enhancing surface homogenization, which is of great significance for practical applications.

To improve the thermal properties of thermite safely and stably, electrostatic spraying was used to prepare the Al/MoO3 thermite. The Al/MoO3 thermites were detected and characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and thermal decomposition experiments were carried out by differential scanning calorimetry (DSC). The heat release of the Al/MoO3 thermite prepared by the electrostatic spray (1044 J·g-1) is significantly higher than that of the thermite prepared by the ultrasonic (692 J·g-1), which is due to more uniform dispersion between Al and MoO3. The initial reaction temperature and activation energy (Ea) of the former keep it steady. Electrostatic spray ensures the safety and stability of the Al/MoO3 thermite. This study provides a new idea for safely and stably improving the thermal properties of thermite by enhancing surface homogenization, which is of great significance for practical applications.

Fluoroelastomer has received increasing attention for energetic materials application due to its high fluorine contents. Different contents (0 wt%-30 wt%) of poly(VDF-ter-HFP-ter-TFE) terpolymer are added into Al/MnO 2 nanothermite.The peak exothermic temperature of thermite reaction for Al/MnO 2 system is about 554 • C with 1070 Jg −1 heat release. After adding terpolymer, it mainly exists in the gap among Al nanoparticles and MnO 2 nanorods, and react with Al and MnO 2 at the range of 350 to 540 • C before the occurrence of the thermite reaction. 10 wt% terpolymer has relatively little effect on the thermite reaction, but for the samples with higher terpolymer content, more nanothermite components react with terpolymer at an early stage. Ignition and combustion performance show terpolymer can reduce ignition current threshold by up to 9.82% and increase combustion duration time at least several times. The potential reasons for the above results are analyzed. This work can shed light on the application of fluoroelastomer in energetic-materials.

Front cover by Jialin Chen et al. Enhancement of Thermal Properties of Al/MoO3 Thermite by Electrostatic Spraying. https://doi.org/10.1002/eng2.12644