A novel nano-energetic system based on bismuth hydroxide

Abstract

We report the first study of the gas generation and thermal wave behavior during the performance of the novel nanoenergetic system based on aluminum and bismuth hydroxide Al-Bi(OH) 3 . The thermodynamic calculations demonstrated that this system is comparable to one of the most powerful known nano-thermite systems, Al-Bi 2 O 3 , in terms of energy capacity per initial charge mass, and may generate more than twice gaseous products 0.0087 mol/g. Differential scanning calorimeter analysis shows that homogenization of as-received powder by using mechanical activation is an essential step to reduce the decomposition energy of bismuth hydroxide by 30 %, which results in nano thermite with higher pressure discharge abilities. The mechanical activation with energy of 450-750 kJ/g is enough to transform micro meter sized particles to sub-micro and nano-sized domain. The resulting nano thermite generated significant value of pressure discharge up to 5.6 kPa m 3 /g.

Hydroxide‐Based Nanoenergetic Materials

“…Out of four examined systems, the formulation based on bismuth hydroxide shown in Figure 5a revealed the highest pressure discharge value of 3.3 MPa in 60 ms timeframe for 200 mg charge, which results in normalized pressure PV m À1 value of 5.6 kPa*m 3 g À1 . This is a very powerful nano-thermite with one of the highest pressure discharge values reported in literature [5], which can be used in high power to mass ratio applications, such as micro-thrusters [18]. The AlÀCu(OH) 2 system, shown in Figure 5b, for the same charge mass generates 0.095 MPa pressure, which is released during 0.3 s timeframe, demonstrating mild thermite characteristics with normalized pressure 0.16 kPa*m 3 g À1 value.…”

“…The pressure discharge is an important feature of nanoenergetic materials [3,5]. The as-prepared nano-thermite formulations with 200 mg mass were placed into Parr Instrument High Pressure cylindrical reactor with 0.342 L vol- 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 ume.…”

“…Aluminum is a common metal fuel for nano-thermites, and oxides are often used as an oxidizer [3][4]. In a recent study [5], it was stated that nano-thermites based on the metal oxides have been studied extensively [6][7][8][9][10][11][12][13][14][15] while metal hydroxide type of oxidizers have not yet been investigated. Furthermore, it was estimated [5] that the bismuth hydroxide-Al system produces twice as much gaseous products per unit mass of initial mixture (0.0087 mol g À1 ) compared to the system Bi 2 O 3 ÀAl (0.00385 mol g À1 ).…”

“…This study investigates 16 nano-thermite aluminum-hydroxide systems by using thermodynamic analysis technique described previously [5,16]. The result of the theoretical analysis was an estimation of equilibrium composition, adiabatic temperature, gas generation, and standard enthalpy of formation for each examined system.…”

Laminar composite structures for high power actuators

“…In this study we employ the nanoenergetic system of Al-I 2 O 5 due to superior generation of highly gaseous phases [14]. In applications where the toxicity of released iodine gas can be concerning, Al-Bi(OH) 3 NGG can be used [15], which releases large amount of water vapors and bismuth. In the medical, biological sciences and ceramic industry, bismuth and its compounds are considered as relatively safe.…”