KEYWORDS Additives, Ammonium perchlorate, Catalyst, High
energetic material, Thermal analysis
INTRODUCTION
Materials such as ammonium perchlorate (AP), ammonium nitrate (AN),
3-nitro-3H-1,2,4-triazol-5-one (NTO), etc release a large amount of heat
and gases during their decomposition. These large gases and heat
released during the components’ decomposition are utilized for various
applications such as destroying a target, propelling objects,
etc.1–3 Changing the combustion or decomposition
behavior of these materials influences the performance of explosive
formulations or solid rockets propellants. Significant research has been
conducted to identify alternative methodologies that focus on finding a
synergistic impact between better stability and improved combustion and
decomposition performance of high energetic
materials.3 Various catalysts were utilized in the
past for changing the thermal decomposition behaviors of high energetic
materials, among which nanosize materials possess a slightly better
catalytic effect for decreasing both thermal decomposition energy and
decomposition of these materials.3–5 Nanosize
materials have a size ranging below 100 nm and differ in properties
compared to their bulk size material because of increased surface area
and quantum confinement effects.6,7 e.g., a Study of
Padwal and Varma8 show that the
Fe2O3 nanoparticles exhibit a better
effect for increasing the burning performance of solid propellants than
micron size Fe2O3. The use of metal
oxides, specifically 3d transition metal oxides were well studied for
improving the thermal decomposition of high energetic
materials.9,10 Recently, Perovskite type oxides (PTOs)
have gained attention for improving the thermal performance of high
energetic materials.11 PTOs have a general formula
ABO3 Where A site is occupied by a larger cation such as
alkaline earth metals and B site is occupied by smaller cations such as
transition metal cations. PTOs can catalyze reactions such as oxidation
of CO, NOX , and reduction of CO2,
N2, O2, etc,12 which
can potentially be produced during high energetic materials’
decomposition process and therefore, can potentially catalyze the
decomposition of these materials.13–16 Use of metal
oxides-reduced graphene oxide (r GO) or other carbon-based
materials were known to improve the heat released during the
decomposition of these high energetic materials as well as further
reducing the decomposition temperature.17,18 This
additional feature of metal oxides containing r GO could be
assigned to r GO’s large surface support for various redox
processes occurring during the decomposition.
In the present work, the catalytic effect of BaZnCuO3(BZC) on the thermal decomposition of inorganic material AP and one
heterocyclic energetic material NTO was investigated. Comparative
studies of the catalytic effect of pure BZC and BZC/rGO composite are
also presented. BZC was synthesized using the sol-gel method and
characterized using powder X-ray diffraction (XRD), Raman, and UV
analysis.
EXPERIMENTAL PROCEDURES
2.1 MaterialsMetal nitrate salts (Ba2+, Zn2+, and
Cu2+) were acquired from SRL Pvt. Ltd., India. GO was
purchased from Merck, India. Go was thermally reduced at 350oC to rGO.19 NTO was synthesized
using previously reported literature20, AP was
acquired from national chemicals.2.2 Synthesis of BZC and BZC/rGOBZC was synthesized using the previously reported sol-gel
citrate-disodium ethylenediaminetetraacetate (EDTA)
method.21 Nitrate salts of metals
Ba2+, Cu2+, and
Zn2+ were mixed in the 2:1:1 ratio followed by the
addition of citric acid and EDTA in 2:1 mole ratio than of total metal
content. The mixture was heated between 90-100 oC to
form a gel. After the combustion of gel in the open air, the obtained
residue was calcined at 700 oC for 4 hours to yield
BZC.
BZC was mixed with rGO in a 2:1 ratio in acetone followed by ultrasound
irradiation for 40 minutes and drying in an oven to yield BZC/rGO
composite.2.3 Preparation of energetic material sample containing
catalystThe obtained BZC and BZC/rGO were mixed with NTO and AP to study their
catalytic influence on the decomposition of AP and NTO. The composition
of the samples and their labeling is depicted in Table 1.
Table 1. Samples for NTO and AP in the presence of different additives
for thermal decomposition studies