Simultaneously Altering the Energy Release and Promoting the Adhesive Force of an Electrophoretic Energetic Film with a Fluoropolymer

Abstract

Energetic coatings have attracted a great deal of interest with respect to their compatibility and high energy and power density. However, their preparation by effective and inexpensive methods remains a challenge. In this work, electrophoretic deposition was investigated for the deposition of an Al/CuO thermite coating as a typical facile effective and controllable method. Given the poor adhesion of the deposited film and the native inert Al2O3 shell on Al limiting energy output, further treatment was conducted by soaking in a Nafion solution, which not only acted as a fluoropolymer binder but also introduced a strong F oxidizer. It is interesting to note that the adhesion level of Al/CuO films was improved greatly from 1B to 4B, which was attributed to Nafion organic network film formation, like a fishing net covering the loose particles in the film. Combustion and energy release were analyzed using a high-speed camera and a differential scanning calorimeter. A combustion rate of ≤3.3 m/s and a heat release of 2429 J/g for Al/NFs/CuO are far superior to those of pristine Al/CuO (1.3 m/s and 841 J/g, respectively). The results show that the excellent combustion and heat release properties of the energetic film system are facilitated by the good combustion-supporting properties of organic molecules and the increase in the film density after organic treatment. The prepared Al/NFs/CuO film was also employed as ignition material to fire B-KNO3 explosive successfully. This study provides a new way to prepare organic–inorganic hybrid energetic films, simultaneously altering the energy release and enhancing the adhesive force. In addition, the Al/NFs/CuO coating also showed considerable potential as an ignition material in microignitors.

Nanoenergetic Materials: Enhanced Energy Release from Boron by Aluminum Nanoparticle Addition

“… 1 , 6 , 16 , 19 , 21 , 22 The presence of these metals relieves the accumulation of liquid boron oxide films by forming porous ternary oxides, 16 , 17 , 19 and their ignition raises the local temperature of the reaction interface, thereby facilitating the more complete oxidation of boron. 19 − 22 Among these metals, aluminum (Al), whose presence on the earth is ubiquitous, has been studied extensively on its own merit, due to its better reactivity, high gravimetric energy density (31 kJ/g), and relatively low melting point. 23 Al can combine with B to form Al borides, 24 which show better thermal stability during storage but release less energy during combustion (40 kJ/g) compared to boron (58 kJ/g).…”

“…Boron has shown high promise as a fuel additive for propulsion and energetic applications due to its high gravimetric (58 kJ/g) and volumetric (140 kJ/mL) enthalpies of oxidation. − Its ignition performance, however, is hindered by the presence of a native oxide on the surface, which melts at relatively low temperatures (450 °C at atmospheric pressure). − The melting of the oxide shell before the solid core clogs the pores leads to particle agglomeration and acts as a diffusion barrier to the incoming oxidizer, thus delaying the boron (B) oxidation. , Attempts to overcome these limitations include surface functionalization of B by organic compounds, − reduction of the oxide, followed by surface passivation using nonthermal plasma processing, and coating with metals to form composites and metal borides by ball milling and high-temperature sintering methods. − Functionalization with organic compounds results in the reduction of the amount of energy released per unit mass due to the presence of less energetic materials on the B surface. Nonthermal plasma processing has been shown to be successful in enhancing the energetic performance over untreated boron but requires low-pressure equipment that is harder to scale-up.…”

“…In the quest to accelerate the combustion performance of B, metals such as Mg, Al, Zr, Fe, Ti, and Li have been used in conjunction with B. ,,,,, The presence of these metals relieves the accumulation of liquid boron oxide films by forming porous ternary oxides, ,, and their ignition raises the local temperature of the reaction interface, thereby facilitating the more complete oxidation of boron. − Among these metals, aluminum (Al), whose presence on the earth is ubiquitous, has been studied extensively on its own merit, due to its better reactivity, high gravimetric energy density (31 kJ/g), and relatively low melting point . Al can combine with B to form Al borides, which show better thermal stability during storage but release less energy during combustion (40 kJ/g) compared to boron (58 kJ/g). , The chemical bonding between the two elements leads to significant ignition delays, adding a further detriment in applications that require fast energy release .…”

“…15,17,20 In the quest to accelerate the combustion performance of B, metals such as Mg, Al, Zr, Fe, Ti, and Li have been used in conjunction with B. 1,6,16,19,21,22 The presence of these metals relieves the accumulation of liquid boron oxide films by forming porous ternary oxides, 16,17,19 and their ignition raises the local temperature of the reaction interface, thereby facilitating the more complete oxidation of boron. 19−22 Among these metals, aluminum (Al), whose presence on the earth is ubiquitous, has been studied extensively on its own merit, due to its better reactivity, high gravimetric energy density (31 kJ/g), and relatively low melting point.…”

First-Principles Investigation of Graphene and Fe2O3 Catalytic Activity for Decomposition of Ammonium Perchlorate

“…In addition, both graphene and Fe 2 O 3 have been proven to be effective catalysts on AP decomposition by reducing the apparent activation energy. , Chen et al revealed that Fe 2 O 3 with hierarchically ordered porous carbon could effectively promote AP decomposition by decreasing the apparent activation energy as well as lowering the decomposition temperature . Generally, the effects of catalysts on AP decomposition are extensively studied by thermoanalytical methods, such as differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and differential thermal analysis (DTA), − which are revealed to be essential to analyze the AP catalytic decomposition. These techniques are based on experiments to assess AP decomposition parameters, such as the decomposition temperature, heat release of decomposition, apparent activation energy, and chemical reaction pathway. ,− However, most of the studies rarely to describe the details and micromechanism of the catalytic process of AP decomposition at the atomic level, which is vital to understand the AP combustion features deeply.…”