Transformation of Combustion Nanocatalysts inside Solid Rocket Motor under Various Pressures

Abstract

In this paper, the dependences of the morphology, particle sizes, and compositions of the condensed combustion products (CCP) of modified double-base propellants (1,3,5-trimethylenetrinitramine (RDX) as oxidizer) on the chamber pressure (<35 MPa) and nickel inclusion have been evaluated under a practical rocket motor operation. It has been shown that higher pressure results in smaller average particle sizes of the CCPs. The CCPs of Ni-containing propellants have more diverse morphologies, including spherical particles, large layered structures, and small flakes coated on large particles depending on the pressure. The specific surface area (SSA) of CCPs is in the range of 2.49 to 3.24 m2 g−1 for propellants without nickel are less dependent on the pressure, whereas it is 1.22 to 3.81 Ni-based propellants. The C, N, O, Al, Cu, Pb, and Si are the major elements presented on the surfaces of the CCP particles of both propellants. The compositions of CCPs from Ni-propellant are much more diverse than another one, but only three or four major phases have been found for both propellants under any pressure. The metallic copper is presented in CCPs for both propellants when the chamber pressure is low. The lead salt as the catalyst has been transformed in to Pb(OH)Cl as the most common products of lead-based catalysts with pressure lower than 15 MPa. When pressure is higher than 5 MPa, the nickel-based CCPs has been found to contain one of the following crystalline phases: Pb2Ni(NO2)6, (NH4)2Ni(SO4)2·6H2O, C2H2NiO4·2H2O, and NiO, depending on the pressure.

UV-Vis Activated Cu2O/SnO2/WO3 Heterostructure for Photocatalytic Removal of Pesticides

“…The presence of sulfur compounds as part of heterostructure matrices, such as SnS 2 /ZnInS 4 [ 28 ], CoTiO 3 /ZnCdS 2 [ 29 ], CdS/CeO 2 [ 30 ], CoWO 4 /CoS [ 31 ], and ZnCdS 2 /MoS [ 32 ], extend the light absorbance spectrum without solving the chemical stability issues in acid or alkaline environments. Composite materials based on g-C 3 N 4 [ 33 ], g-C 4 N 6 [ 34 ], and r-GO [ 35 ] exhibit high surface-active materials able to efficiently eliminate the pollutants using both absorption and photocatalytic processes.…”

Effects of Nanosized Metals and Metal Oxides on the Thermal Behaviors of Insensitive High Energetic Compound ICM-102

“…It has been reported that many nanosized metals (Al, Mg, B, W, Zr, Ni, Cu, Fe, Ag, and Co) and metal oxides (e.g., Pb-, Cu-, Bi-, and Fe-based oxides) are widely used in solid propellants as fuels and the burning rate catalysts. , For instance, the nano-CuO and nano-Fe 2 O 3 have better catalytic effects than the microsized ones, , whereas the nano-Al can not only increase the energy content, but also enhance the burn rate of propellants with reduced pressure exponent under high pressure ranges . Furthermore, the thermal decomposition is the initial stage of combustion and explosion of materials, and the performance of thermal decomposition is an essential index that determines the combustion and explosion of materials. − Therefore, the thermal behaviors and decomposition mechanisms of ICM-102 under the effects of nanosized metals and metal oxides must be investigated before the ICM-102 is applied in propellants.…”