Processing and Ignition Characteristics of Aluminum-Bismuth Trioxide Nanothermite System

During the past few years, significant progress has been made in the development of new nanoenergetic materials consisting of mixtures of metal and oxidizer nanopowders. It has been found that such reacting mixtures release energy by 2 to 3 orders of magnitude faster than similar systems consisting of micron-size reactants. In some cases, combustion-front velocities reach hundreds of meters per second. These new reacting systems find applications in both civilian and military sectors, including fast vaporization of active chemical components, fast heating of thermal batteries and main ingredients of new environmentally benign percussion primers or electric matches. This paper presents experimental results on ignition and combustion front propagation characteristics in the Al-Bi2O3 nanothermite system. The effect of different coatings and inhibitors of the reaction of aluminum with water in the presence and without the presence of bismuth trioxide is discussed. In addition, thermodynamic analysis of the Al-Bi2O3 reacting system and reaction kinetics measurements using differential scanning calorimetry are presented. Electrostatic discharge sensitivities of Al-Bi2O3, Al-MoO3, and Al-Fe2O3 nanothermite systems were determined. It was found that all investigated nanothermite systems showed very high levels of electrostatic discharge sensitivity in the form of dry and loose powder.