Decomposition Of Ammonium Perchlorate Research Articles

Model-free kinetic analysis of multi-step thermal decomposition of ammonium perchlorate coated with reduced graphene oxide

Model-free kinetic analysis of multi-step thermal decomposition of ammonium perchlorate coated with reduced graphene oxide

Enhancement of aluminum powder reaction behavior at high temperatures—Aluminum powders with “sea urchin structure” coated by AP

To solve the problem of high ignition temperature of aluminum powder and easy to burn into blocks at high temperatures, “sea-urchin-structured” aluminum powders (μAl@nAl) obtained by electro-explosion were coated by ammonium perchlorate (AP) on its surface. AP in a high-temperature environment has a rapid decomposition, then the gas production will promote the dispersion of aluminum powder into micro-clusters, thus preventing the aluminum powder agglomeration during the combustion process. The micro-nano composite aluminum powder (μAl@8 %nAl) and physical mixed aluminum powder (μAl + 8 %nAl) coated by AP were completed by solvent volatilization method. The coating surface was observed by scanning electron microscopy. The heat of combustion and pressure curves for different AP contents were tested using a chamber with a constant volume, and the ignition and combustion performance of the AP samples were investigated using a carbon dioxide (CO2) laser ignition device. The AP samples shortened the ignition delay time and improved the combustion performance in the fixed-volume combustion and laser ignition tests. Under atmospheric air, taking into account the theoretical calorific value, pressure curve, and combustion performance, the optimal AP content is 10 %. The thermal decomposition process of two samples was further analyzed using the thermogravimetric and differential scanning calorimetry (TG-DSC) method. The decomposition of AP advanced the first oxidation peak of aluminum powder; however, in the second step oxidation peak, the peak temperature of μAl@8 %nAl@10 %AP sample was delayed compared to μAl + 8 %nAl@10 %AP sample. High-voltage electrical explosions and high-energy laser-induced air shock waves were created to simulate the high-temperature environment of the detonation reaction zone, and pictures of the reaction process and pressure change curves of the “sea urchin structure” aluminum powder coated by AP at high temperatures were recorded. The results showed that the “sea urchin structure” aluminum powder coated by AP exhibited better combustion performance, and the reaction degree of the aluminum powder had been deepened.

Cu/Carbon Aerogels Derived from HKUST-1 for the Thermal Decomposition of Ammonium Perchlorate

Cu/Carbon Aerogels Derived from HKUST-1 for the Thermal Decomposition of Ammonium Perchlorate

Preparation of Zn-Co Bimetallic Catalysts and Their Catalytic Properties for Thermal Decomposition of Ammonium Perchlorate.

This research delves into the preparation of heteronuclear bimetallic catalysts and explores their catalytic properties in the thermal decomposition of ammonium perchlorate (AP). The study's central focus is on enhancing the thermal decomposition characteristics of AP and, consequently, the combustion performance of composite solid propellants. The synthesized materials underwent structural characterization by XRD, XPS, SEM, and FTIR. Catalytic properties were examined using DTA tests. Notably, catalysts derived from calcination at 500 °C exhibited heightened catalytic activity. They advanced the pyrolysis temperature by 135.4 °C and reduced the activation energy by 82.38 kJ/mol compared with pure AP. To further elucidate the decomposition mechanism of AP, the investigation also employed a combined approach involving DSC-TG-FTIR-MS analysis.

Energetic transition metal complexes based on 1‐allylimidazole and nitrocyanamide: Syntheses, characterizations and catalytic performances on the thermal decomposition of ammonium perchlorate

AbstractTo explore combustion catalysts for solid propellants, four novel energetic coordination compounds were prepared with the anion of nitrocyanamide (NCA) as the ligand and 1‐allyl‐imidazole (AIM) as the ligand, and transition metals Mn, Co, Ni, and Cu as the central ions. The structures of these compounds were [Mn(AIM)4] (NCA)2 (1), [Co(AIM)4](NCA)2 (2), [Ni(AIM)4](NCA)2 (3), [Cu(AIM)4](NCA)2 (4). The results showed that all of the compounds possessed high energy density, and compound 2 had a mass energy density (Eg) of 17.9 kJ g−1 and a volume energy density (Ev) of 25.59 kJ cm−3. The catalytic effect of these compounds on the thermal decomposition of ammonium perchlorate (AP) was studied using DSC. The addition of 5 % catalyst to AP samples advanced the high‐temperature decomposition temperature and significantly increased the heat release. Compound 4 exhibited the best catalytic performance, with an increased heat release of 1739 J g−1, decomposition temperature advanced by 88.2 °C, and activation energy reduced to 74.74 kJ mol−1. These results demonstrate the potential of these compounds as combustion catalysts for solid propellants.

Based on the strong oxidant AP adjustment strategy to obtain Al/AP@PVDF composite material with excellent energy release performance

In this paper, ammonium perchlorate (AP) as a strong oxidant has been added into Al/polyvinylidene difluoride (PVDF) nanothermites. Based on homogeneous structure of PVDF, shorter reaction contact between components can be obtained for more outstanding ignition and combustion performance. Water contact angle experiments were conducted to evaluate the hydrophobicity of the composite films, indicating that the suitability of composite material has enhanced under wet environment. According to TG-DSC results, the thermal decomposition of AP can improve the whole heat release process, which theoretically has excellent combustion performance advantages. Constant volume pressure tests were conducted to assess the energy release properties of the films compared with Al@PVDF films. Combustion performance in air was evaluated by employing optical sensors and a high-speed camera to measure factors such as the ignition delay time, light intensity and combustion flame propagation. After adding 15% AP, the maximum pressure of Al/AP@PVDF film is 0.0960 Mpa, and that of Al@PVDF film is 0.0805 Mpa. The maximum pressure of the film is increased by nearly 19.25%. Compared with Al@PVDF film, the ignition delay time of Al/AP@PVDF film is shortened by 45 ms, and the light intensity is increased by nearly 93.39%. However, excessive AP content adversely impacted film formation efficiency, leading to the deterioration of various properties. Therefore, an optimal AP content of approximately 15% in Al/AP@PVDF system was finally identified.

In Situ MOF-74-Pyrolysis-Generated Porous Carbon Supporting Spinel Cu0.15Co2.85O4/C Boosts Ammonium Perchlorate Accelerating Decomposition: Precise Cu Doping Modulating Oxygen Vacancy Concentration.

As one of the main components of solid propellant, ammonium perchlorate (AP) shows slow sluggish decomposition kinetics with unconcentrated heat release. To achieve efficient catalytical decomposition, it is a significant challenge to design reasonable catalyst structure and explore the interaction between catalyst and AP. Herein, a series of porous carbon supported spinel-typed homogeneous heterometallic composites CuxCo3-xO4/C via pyrolysis of MOF-74-Co doped Cu. On basis of precise electronic-structure-tuning through modulating Cu/Co ratio in MOF-74, Cu0.15Co2.85O4/C with 5% Cu-doping featuring oxygen vacancy concentration of 26.25% exhibits the decrease to 261.5°C with heat release up to 1222.1 J g-1 (456.9°C and 669.2 J g-1 for pure AP). The detail process of AP accelerated decomposition is approved by TG-DSC-FTIR-MS technique. Density functional theory calculation revealed that in the Cu0.15Co2.85O4/C, the distinctive ability for NH3 catalyzed oxidation assisted with absorption performance of active porous C boosts accelerating AP decomposition. The findings would provide an insight for perceiving and understanding AP catalytic decomposition.

Synthesis of Cu-MOF-derived complex copper–chromium oxides and their catalytic study on the thermal decomposition of ammonium perchlorate

In this work, a series of complex copper-chromium oxides were prepared by adjusting the molar ratio of Cr3+/Cu2+ using MOF-199 as a template. X-ray diffraction (XRD), scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) were used to characterize the structure, microscopic morphology and valence information of the samples. The specific surface area of the sample was estimated by the Brunauer-Emmett-Teller method (BET), and the pore size parameters of the sample were obtained by using the Barrett-Joyner-Halenda (BJH) model. The effect of the samples on the thermal decomposition process of ammonium perchlorate (AP) was investigated by differential scanning calorimetry-thermogravimetric analysis. The results show that the copper and chromium oxides in the complex exhibit good catalytic effects. Among them, CuCr(0.8) had the best catalytic effect, reducing the peak pyrolysis temperature of AP by 95.7 °C, increasing the heat release by 817 J/g, and reducing the reaction activation energy by 62.4 kJ/mol. Real-time FTIR was used to characterize the gas products during the thermal decomposition of AP, and the gas products of AP with CuCr(0.8) catalyst were different from those of pure AP, which may also be the reason for the increase of AP heat release after adding CuCr(0.8) catalyst.

Evaluation of the Combustion Properties and Catalytic Activity of MgAlB Energetic Ternary Particles

ABSTRACT Boron powder possesses significant potential for use as a combustible agent in energetic materials, owing to its superior combustion thermodynamic properties. However, the powder’s tendency to form an oxide layer on its surface results in delayed ignition, reduced combustion efficiency, and compromised energy advantage. To enhance the ignition and combustion properties of boron powder, we prepared boron-based energetic composites containing flammable metals (MgxAl1-xB2) through high-temperature sintering. These were then characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS). The combustion heat of these alloy powders were measured using an oxygen bomb calorimeter, while their catalytic performance on the thermal decomposition of ammonium perchlorate (AP) was analyzed using differential scanning calorimetry (DSC) and differential thermal analysis (DTA). The results indicate that compared with boron, the MgxAl1-xB2 powders are more flammable, require less oxygen, exhibit a higher combustion efficiency and exothermic advantage. Especially, the Mg0.9Al0.1B2 and MgB2 alloy exhibit optimal combustion heat values of 39,094.92 and 37,693.90 J·g−1, respectively. They significantly enhance the thermal decomposition of AP and reduce the activation energy by over 20%.

MOF-74 derivatives spinel CuCo2O4/C with d-band center modulation for accelerating ammonium perchlorate thermolysis

As one of main components of solid propellant, ammonium perchlorate (AP) shows slow sluggish decomposition kinetics with unconcentrated heat release. In the past, researchers have done a lot of work using spinel oxides as combustion modifiers to improve the combustion performance of AP. However, AP decomposition process is very complicated, and the relationship between intrinsic activity of cobalt-based spinel catalysts and AP combustion process is still unclear. In this paper, a series of cobalt-based spinel structure catalysts, MCo2O4/C, were prepared by pyrolysis of cobalt-containing bimetal MOF-74 and used as AP combustion catalysts. All of them showed excellent catalytic performance, among which CuCo2O4/C had the best catalytic activity. It effectively reduces the activation energy of the reaction, speeds up the reaction rate, and reduces the peak temperature of the AP decomposition reaction by 161.2 ℃, and the reaction rate k is 10.28 times of Co3O4/C. XPS and NH3-TPD tests indicate that substitution CoTd2+ with Cu2+ increases the ratio of Co3+/Co2+ and enhance interaction between NH3 and catalyst. The essential reason is that Cu–O-Co corner sharing effect changes electron distribution and enhances CoOh3+ Lewis acidity accompanied with the proximity of d-band center to EF by density functional theory calculations.

Bioinspired Fabrication of an Insensitive Ammonium Perchlorate Core-Shell Composite with Polydopamine Coating.

In this research, an ammonium perchlorate/polydopamine (AP/PDA) core-shell composite was prepared in a non-aqueous solution to reduce the mechanical sensitivity of ammonium perchlorate (AP). The result showed that the AP/PDA core-shell composite could be successfully constructed in ethyl acetate solution with an AP recovery rate that reached 86%. The mechanical sensitivity of the obtained AP/PDA core-shell composite was significantly reduced with a PDA content of only 0.76%. The DSC and TG also indicated that the coating of PDA showed catalytic activity in the thermal decomposition of AP with a lower decomposition temperature and a decreased Ea value of AP. Thus, this study proposed a simple strategy for achieving a good balanced between harnessing the energy and ensuring the safety of ammonium perchlorate by significantly reducing its mechanical sensitivity by using a very low polydopamine coating layer content, and this shows great potential for the design and fabrication of insensitive energetic composites for use in propellants.

Highly efficient thermal decomposition of AP through intimately encapsulating in 3DOM CoFe2O4 spinel

Designing highly active catalysts and constructing the interface between ammonium perchlorate (AP) and catalysts are effective strategies for achieving efficient thermal decomposition of AP, which is an urgent need for developing AP based composite solid propellants. Herein, we report an impregnation vacuum freeze-drying strategy to encapsulate AP in an independent three-dimensionally ordered macroporous (3DOM) CoFe2O4 (3D CFO) spinel, resulting in a novel 3D CFO encapsulated AP nanocomposite materials (AP-3DCNCs). The connected pores of 3D CFO provide a model structure for the growth of AP nanocrystals, while the impregnation vacuum freeze-drying strategy ensures the uniform distribution of AP crystals in pores, effectively achieving the size effect of AP nanocrystals (39.88 ∼ 55.50 nm). By adjusting the loading capacity of the AP, the AP-3DCNCs configuration was effectively controlled. The thermal decomposition of AP-3DCNCs is greatly enhanced due to their unique configuration. The high-temperature decomposition temperature is significantly reduced by 180.06–141.78 °C, and the maximum equivalent heat release increased by 2.03 times. It can be foreseen AP-3DCNCs are attractive nanocomposites for the thermal decomposition of AP, and these results provide a convenient strategy for the preparation of transition metal-based composite catalysts with promising applications in the field of solid propellants.

Impacts of metal oxide crystalline structure on the decomposition of solid propellants under combustion heating rates

Ammonium perchlorate (AP) has been the oxidizer of choice for composite solid propellants for decades and has been the object of decomposition studies for safety monitoring. Typically, studies perform differential scanning calorimetry (DSC) or thermogravimetric analysis (TGA) to show how metal oxides (MO) commonly incorporated into propellants alter AP decomposition rates and completeness of reaction. Most past decomposition work studies temperatures below the crystal phase transition (240°C) from orthorhombic phase to cubic, which impose internal stresses within the lattice of AP particles. Phase change induces a partial decomposition, which does not follow a shrinking core behavior; instead, it develops a network of pores up to a few microns in size throughout. During low-temperature decomposition, particles lose approximately 30-40 % of their mass. Simultaneous DSC/TGA (STA) use low heating rates for combustion environments but offer information on MO's catalytic and electron transport modifications. This work demonstrates how the crystalline morphology MO additives mechanistically alter the combustion properties of composite propellants by identifying modes for promoting decomposition in AP and HTPB. MO morphology determines the electron structure of the molecule, which sets the band gap properties of the particles. This study evaluated different morphologies and a range of MOs to identify the most active MO for decomposing A.P. Kissinger analysis was applied using STA data at heating rates of 10-, 20-, and 30-°C/min revealing significant shift in the high-temperature decomposition with a range of metal oxides. Higher heating rates were evaluated using CO2 laser ignition to identify the time to first gas using the MO that offers the best heat absorption, such as the aluminum oxides. This higher heating rate was found do more accurately represent the changes in the combustion rates in the final propellant mixture. Additionally, it was shown that electron transport additives like CuO show the most significant impact on combustion, and thermal absorbers offer the lowest impact on AP/HTPB combustion. This understanding offers a new approach to propellant design not previously presented and suggests future testing for tailoring the use of metal oxides in propellants.

Titanium a novel catalyst and high energy dense material: an opportunity for composite propellants with enhanced performance

ABSTRACT Whereas aluminum with combustion enthalpy of 32 KJ/g is the universal reactive metal particles, its passive protective oxide layer could encounter its efficient combustion. While titanium can offer low combustion enthalpy (20 KJ/g), it does not expose passive oxide layer. The impact of both reactive particles on ammonium perchlorate (AP) decomposition enthalpy was investigated via DSC. Aluminum and titanium particles secured an increase in AP decomposition enthalpy by 46.9%, and 80.7% respectively. This significant impact of titanium particles was ascribed to full exploitation of metal energy content. The impact of titanium particles on AP decomposition kinetics was assessed via Kissinger, KAS, and FWO models using TGA. Whereas virgin AP demonstrated average apparent activation energy of 155 KJ/mol, Ti/AP demonstrated average apparent activation energy of 141.2 KJ/mol. Solid rocket propellant formulations based on 17 wt % metal (Al or Ti) were developed via mixing and vacuum casting. Ballistic performance was investigated using small-scale ballistic evaluation rocket motor. Ti-based formulation offered an increase in propellant burning rate, average operating pressure, average thrust by 18.2%, 26.5%, and 19.7% respectively. It was concluded that titanium particles have a dual effect as efficient high energy dense material and as a catalyst.

The significant role of passive oxide layer on reactive metal combustion: insights into composite solid propellant with superior performance

ABSTRACT Passive oxide layer could expose a significant impact on reactive metal combustion. Boron and aluminum experience combustion enthalpy of 59.3 and 31.1 KJ/g and passive oxide layer of 200 and 7 nm, respectively. In this study, surface oxygen of born and aluminum particles (10 µm) was quantified via EDAX analysis. Boron and aluminum demonstrated surface oxygen content of 14.6 and 7.2 wt %, respectively. Reactive particles were integrated into ammonium perchlorate (AP) oxidizer. While boron demonstrated decrease in AP decomposition enthalpy by −14.8%; aluminum offered an increase in AP decomposition enthalpy by 60.8% using DSC. Whereas, aluminum oxide layer could be pealed out more effectively; boron passive oxide layer could melt with the evolution of an insulating barrier. Aluminum particles offered decrease in AP apparent activation energy by 68%, 105%, and 76% using Kissinger, Kissinger-Akahira-Sunose (KAS), and Flyn and Wall (FWO) models, respectively. Solid propellant formulations were developed; ballistic performance was assessed using small-scale rocket motor. Aluminum particles demonstrated stable combustion process with enhanced specific impulse and total pressure impulse compared with boron. Additionally, aluminum particles demonstrated stable burning with pressure exponent of 0.19 compared with 0.4 for boron particles.

Unravelling the reaction mechanism for the AP decomposition over MgO: A density functional theory study and microkinetic simulation

The detailed reaction mechanisms for the decomposition of ammonium perchlorate (AP), an essential component of solid composite propellants, are poorly understood due to the ultrafast and complex reactions. Density functional theory and kinetic simulation are utilized to calculate the decomposition reaction of AP on the surface of magnesium oxide and present a detailed decomposition network. Using a proton transfer mechanism, NH3 and HClO4 are the major production at low-temperature decomposition of AP, involving two elementary steps. AP is completely decomposed in the high-temperature reaction stage. In this work, it is found that the decomposition of NH3 is mainly in the form of oxidative dehydrogenation, while HClO4 proceeds along the pathway HClO4→ClO3→ClO2→ClO→Cl, and the final nitrogen oxides, chlorine oxides are formed. These simulations provide offer atomic-level understanding of the complex reaction kinetics of AP, which can be applied to explore the reaction mechanisms of other metal oxides.

Microflower-like Fe-Co-MOF with enhanced catalytic performance for decomposition of ammonium perchlorate and combustion of ammonium perchlorate-based composite propellants

Ammonium perchlorate (AP) serves as a crucial component in solid propellants. Enhancing its thermal decomposition with catalysts improves the combustion performance of solid propellants significantly. To enhance the catalytic performance of metal-organic frameworks (MOFs) on AP, this study controlled the morphology of MOFs by adding metal atoms, resulting in a Fe-Co-MOF catalyst with higher specific surface area and dual-metal synergistic effect. The catalytic effect of the catalyst on AP was investigated using DSC and TG-IR, followed by studying its influence on the combustion performance of AP-based composite propellants. The results show that the introduction of 5% Fe-Co-MOF reduced the decomposition temperature of AP to 298.6 °C, decreased the activation energy to 151.6 kJ mol-1, and increased the heat release by 110.6%. Additionally, the ignition delay of the propellant decreased by 71 ms, and the combustion rate increased by 43.8%. Mechanistic studies demonstrate that the abundant catalytic sites and oxygen vacancies of Fe-Co-MOF facilitate the charge transfer rate during the AP thermal decomposition process and promote the increase in AP heat release by suppressing the high-temperature conversion of N2O. This research paves the way for enhancing the application of MOF materials in AP-based solid propellants.

Catalytic properties of 3D flower-likeMgCo2O4/MXene composites for the thermal decomposition of ammonium perchlorate by one-pot synthesis

The catalytic active sites of the materials have a major role in the catalytic activity of nanocatalytic materials for the heat thermal decomposition of ammonium perchlorate. By adopting one-pot strategy to load MgCo2O4 onto MXene nanosheets, we were able to create highly dispersed MgCo2O4/MXene composites that improved the dispersion of the nanoparticles and increased the catalytic active sites. The MgCo2O4/MXene catalytic active sites were clearly optimized (Specific surface area increased from 115.4 of MgCo2O4 to 168.8 m2·g−1), according to the BET results. The performance tests demonstrated that the MgCo2O4/MXene composite effectively decreased the thermal decomposition temperature of AP, and the MgCo2O4/MXene composite significantly reduced the peak decomposition temperature of AP by 208.3 °C (from 471.2 °C of pure AP to 262.9 °C). The decomposition heat of AP increased from 782 J·g−1 of pure AP to 1453 J·g−1. In addition, the apparent activation energy of AP dropped from 296.19 kJ·mol−1 to 119.48 kJ·mol−1. Application of MgCo2O4/MXene composite to AP/HTPB-based composite solid propellants (CSPs) for combustion experiments resulted in an appreciable reduction in ignition delay time of ∼ 45 ms (from ∼ 51 ms to ∼ 6 ms). The highly dispersed MgCo2O4/MXene composite was a positive catalyst for AP-based composite solid propellant.

Encapsulation of ferrocenes in microporous ZIF-67 channels for boosting their anti-migration tendency and catalytic activity in ammonium perchlorate thermal decomposition

The enhancement of the anti-migration performance of ferrocene-based burning rate catalysts (BRCs) and their catalytic influence on ammonium perchlorate (AP) combustion in composite solid propellants through the confinement effect is acknowledged as an effective strategy. In this investigation, FcR@ZIF-67 nanocomposites were fabricated by introducing commercial ferrocenes (FcR = Cat, NBF, TBF, and NOF) into microporous ZIF-67 nanochannels. In the catalysis performance evaluations, the Cat@ZIF-67 exhibited prominent combustion catalytic efficiency on AP thermal decomposition by advancing the AP pyrolysis temperature peak by 111.4 °C and increasing its release heat by 2.3 times. Moreover, the anti-migration tests demonstrated that FcR@ZIF-67 composites remain predominantly immobile during prolonged storage at 50° C. The investigation results of in-situ solid FTIR, TG-FTIR-MS, and theoretical calculations for the AP thermal degeneration with Cat@ZIF-67 as a promoter, indicated that, in the oxygen-rich environment of AP, the thermal disintegration of Cat@ZIF-67 creates a Fe2O3-Co3O4 heterostructure that facilitated the generation of reactive oxygen species. This, in turn, accelerated the pyrolysis of AP and formed more thermodynamically stable gaseous products, advancing its exothermic degradation temperature and increasing its release heat. Based on these discoveries, a hypothetical catalytic mechanism for the thermal decomposition of AP is proposed.

A functionalised interface for controllable decomposition of ammonium perchlorate by a self-assembly method

A functionalised interface construction strategy was developed by coating an ammonium perchlorate (AP) surface with quaternary ammonium cation surfactants using a self-assembly method. The functionalised interface transforms AP decomposition from high temperature decomposition into low temperature decomposition, and provides pressure-sensitive control over the mass ratio of AP decomposition in the two stages. Further study using molecular dynamics simulations and density functional theory reveal that the functionalised interface hinders the adsorption of NH3 molecules and promote the adsorption and decomposition of ClO4 on the AP surface, all of which could contribute to controlling AP decomposition.