Low air pressure self-sustaining combustion performances of 3D direct writing Al/CuO film

The application and optimization of nano-composite energetic materials in the extreme and particular environment have become a subject of wide concern. Additionally, the design and selection of metastable intermixed composites (MICs) films in low pressure environment is the key problem to explore its future application. Here, 90 wt% high loading Al/CuO nanothermite films were prepared by a simple 3D direct writing approach. Four films with different thicknesses (66, 128, 152, 182 pm) were designed and their combustion properties were tested respectively. The low pressure combustion results show that the self-sustained burning rate of the film (thicker than 66 pm) can be adjusted and controlled in various air pressure environments (101-60 kPa). The selfsustained burning rate of film is affected by both thickness (66-182 pm) and air pressure (101-60 kPa). The lower the air pressure, the lower the burning rate. The greater the thickness, the higher the burning rate. The 66 pm film self-sustainedly burns at atmospheric pressure and extinguishes when the pressure was significantly reduced. The self-sustained combustion rates of the 128 and 152 pm film decreases with decreasing pressure until the pressure drops to 75 and 60 kPa respectively. The 182 pm film keeps self-sustained combustion in a manner of deflagration which is almost unaffected by air pressure, even when the pressure drops to 10 kPa. Simultaneously, it is found that the ignition temperature of the film is almost not affected by pressure. In addition, it is verified that the film has performances of excellent hydrophobic and combustion through air-water interface. These can cope with complex environmental humidity.