The Role of MoO3 and Fe2O3 in the Thermal Decomposition of Ammonium Perchlorate

1994 ◽  
Vol 59 (10) ◽  
pp. 2253-2261 ◽  
Author(s):  
Samih A. Halawy ◽  
Mohamed A. Mohamed
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
High Temperature ◽  
Thermogravimetric Analysis ◽  
Surface Area ◽  
Ammonium Perchlorate ◽  
Bet Method ◽  
Xrd Techniques

The effect of addition of MoO3 and Fe2O3 as well as mixtures of the two oxides (calcined in air at 500 °C) on the thermal decomposition of ammonium perchlorate (AP) was studied using thermogravimetry (TGA) and derivative thermogravimetric analysis (DTG). The catalysts calcined at 500 °C were characterized using TPR, XPS and XRD techniques. The surface area of the catalysts was determined by means of the conventional BET method. The results are discussed in terms of the recently published mechanism in which nitryl perchlorate is supposed as an intermediate in the thermal decomposition of pure AP. The correlation between the surface area and activity of the catalysts in the thermal decomposition of AP has been done. The activation energy (∆E) for non-catalyzed and catalyzed high-temperature thermal decomposition of AP were calculated from the TGA results using the Coats-Redfern equation.

Role of silver compounds in promoting the thermal decomposition of ammonium perchlorate

1986 ◽  
Vol 1 (3) ◽  
pp. 235-251 ◽  
Author(s):  
Andrew K. Galwey ◽  
Mohamed A. Mohamed ◽  
David S. Cromie
Keyword(s):  
Thermal Decomposition ◽  
Ammonium Perchlorate ◽  
Silver Compounds

scholarly journals High Temperature Degradation Mechanism of Concrete with Plastering Layer

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 398
Author(s):  
Chihao Liu ◽  
Jiajian Chen
Keyword(s):  
Mechanical Properties ◽  
Mechanical Property ◽  
Thermal Decomposition ◽  
Electron Microscope ◽  
High Temperature ◽  
Thermogravimetric Analysis ◽  
Degradation Mechanism ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Scanning Electron

At present, the research on the high temperature degradation of concrete usually focuses on only the degradation of concrete itself without considering the effect of the plastering layer. It is necessary to take into account the influence of the plastering layer on the high temperature degradation of concrete. With an increase in the water/cement ratio, the explosion of concrete disappeared. Although increasing the water/cement ratio can alleviate the cracking of concrete due to lower pressure, it leads to a decrease in the mechanical properties of concrete after heating. It is proved that besides the water/cement ratio, the apparent phenomena and mechanical properties of concrete at high temperature can be affected by the plastering layer. The plastering layer can relieve the high temperature cracking of concrete, and even inhibit the high temperature explosion of concrete with 0.30 water/cement ratio. By means of an XRD test, scanning electron microscope test and thermogravimetric analysis, it is found that the plastering layer can promote the rehydration of unhydrated cement particles of 0.30 water/cement ratio concrete at high temperature and then promote the mechanical properties of concrete at 400 °C. However, the plastering layer accelerated the thermal decomposition of C-S-H gel of concrete with a water/cement ratio of 0.40 at high temperature, and finally accelerate the decline of mechanical property of concrete. To conclude, the low water/cement ratio and plastering layer can delay the deterioration of concrete at high temperature.

The low temperature thermal decomposition of ammonium perchlorate: nitryl perchlorate as the reaction intermediate

1984 ◽  
Vol 396 (1811) ◽  
pp. 425-440 ◽  
Keyword(s):  
Thermal Decomposition ◽  
Low Temperature ◽  
Ammonium Perchlorate ◽  
Bond Formation ◽  
Covalent Bond ◽  
Subsequent Reaction ◽  
Temperature Decomposition ◽  
Covalent Bond Formation ◽  
Localized Reaction

We identify nitryl perchlorate as the essential intermediate in the low temperature thermal decomposition of ammonium perchlorate AP. Evidence supporting this identification includes the analytical detection of an oxidized nitrogenous species in partly reacted AP and the ability of ammonium nitrate and several other nitrates to markedly reduce the induction period to decomposition of AP and to accelerate the subsequent reaction. It is also shown that the measured rate of the reaction of pure AP is in very satisfactory agreement with that estimated to result from this amount of NO 2 ClO 4 present. This mechanism differs from those currently accepted, in which the controlling process is believed to involve the transfer of either a proton or an electron. Our proposal is based on the known instability of NO 2 ClO 4 at reaction temperature ( ca . 500 K), the enhanced reactivity compared to the ionic alkali perchlorates being ascribed to covalent bond formation O 2 NO─ClO 3 . Subsequent reactions of the products of breakdown of this species, NO + , ClO 3 - and 2O or O 2 , are regarded as capable of oxidizing reactant NH 4 + (→NO 2 + ), thus regenerating the intermediate. Localized reaction in migrating ‘particles’ of fluid NO 2 ClO 4 , advancing through the reactant and leaving a residue of porous NH 4 ClO 4 , explains the unusual, incomplete low temperature decomposition that is characteristic of AP. The article reports comparative kinetic data for the decomposition of pure AP and the reaction initiated by various added nitrates. Rate studies are complemented by scanning electron microscope examinations of the geometry of interface development and the structure of the decomposed salt. From these and analytical results the role of nitryl perchlorate in AP decomposition is discussed.

scholarly journals Nonisothermal Thermogravimetric Analysis of Thai Lignite with High CaO Content

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Pakamon Pintana ◽  
Nakorn Tippayawong
Keyword(s):  
Activation Energy ◽  
Thermal Decomposition ◽  
Thermogravimetric Analysis ◽  
Combustion Kinetics ◽  
Heating Rates ◽  
Thermogravimetric Method ◽  
Degradation Behaviors ◽  
Fwo Method ◽  
Free Cao ◽  
Kinetics Of

Thermal behaviors and combustion kinetics of Thai lignite with different SO3-free CaO contents were investigated. Nonisothermal thermogravimetric method was carried out under oxygen environment at heating rates of 10, 30, and 50°C min−1from ambient up to 1300°C. Flynn-Wall-Ozawa (FWO) and Kissinger-Akahira-Sunose (KAS) methods were adopted to estimate the apparent activation energy (E) for the thermal decomposition of these coals. Different thermal degradation behaviors were observed in lignites with low (14%) and high (42%) CaO content. Activation energy of the lignite combustion was found to vary with the conversion fraction. In comparison with the KAS method, higherEvalues were obtained by the FWO method for all conversions considered. High CaO lignite was observed to have higher activation energy than the low CaO coal.

Preparation of Carbon-Coated Nano-Fe, Co Particles and their Effects on the Thermal Decomposition of Ammonium Perchlorate

2010 ◽  
Vol 152-153 ◽  
pp. 309-314 ◽  
Author(s):  
Jun Zhao ◽  
Wei Liang Zhou ◽  
Fu Ming Xu
Keyword(s):  
Thermal Decomposition ◽  
Particle Size ◽  
High Temperature ◽  
Ammonium Perchlorate ◽  
Cation Exchange Resin ◽  
Carbon Matrix ◽  
Decomposition Temperature ◽  
Temperature Decomposition ◽  
Carbon Coated ◽  
Size And Morphology

Nano Metal/C (Metal=Fe, Co) composite materials, in which nano iron and cobalt particles were uniformly distributed in carbon matrix, was prepared by pyrolysis of M-exchanged cation exchange resin(M-PAA). X-ray diffraction (XRD), Transmission Electron Microscope (TEM) results showed the particle size and morphology of nano iron and cobalt in M/C could be controlled by pyrolytic temperature. The particle size of Co and Fe in M/C obtained at 500 was respectively 15-40 nm and 10-35 nm. DTA was employed to test the thermal decomposition of ammonium perchlorate (AP) in the M/C and AP mixture. Results indicated the decomposition temperature at high-temperature decomposition of AP was lowered with the addition of amount of M/C-500, and the high temperature decomposition peaks of AP respectively lowered as much as 145.2°Cand 68.3°C with adding amount of 5% of Co/C and Fe/C obtained at 500 . The high and low temperature decomposition peaks of AP overlapped with addition of Co/C.

Long-Range Diffusion of Hydrogen in Solid-Solution PdCe Alloys as Deduced from Absorption Experiments

2008 ◽  
Vol 273-276 ◽  
pp. 381-387 ◽  
Author(s):  
Giovanni Mazzolai
Keyword(s):  
Activation Energy ◽  
Solid Solution ◽  
Thermal Decomposition ◽  
Diffusion Coefficient ◽  
High Temperature ◽  
Diffusion Constant ◽  
Absorption Data ◽  
Friction Measurements ◽  
And Diffusion ◽  
Diffusion Of Hydrogen

The diffusion of H and the thermal decomposition of hydrides have been investigated at high temperatures in two PdCe alloys of composition 5% and 9% Ce. It has been found that the H diffusion coefficient obeys an Arrhenius-type of law with the following values of the activation energy W and diffusion constant D0, ( )     = ± × = ± − s m D W eV 2 7 0 2 2 10 0.20 0.02 (Pd95Ce5 alloy) ( )     = ± × = ± − s m D W eV 2 7 0 2 1 10 0.24 0.01 (Pd91Ce9 alloy) The high-temperature absorption data match the low-temperature ones deduced from internal friction measurements, indicating that Ce atoms do not act as strong trapping centres for H. Thermal decomposition of hydrides in the Pd95Ce5H0.008 alloy occurs in a single stage showing a homogeneous solid solution state of the H-Me system.

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