scholarly journals Fuel Ratio and Additives Influence on the Combustion Parameters of Novel Polyurethane-based Flares

2021 ◽  
Vol 57 (4) ◽  
pp. 109-124
Author(s):  
Cristiana Epure ◽  
Tudor-Viorel Tiganescu ◽  
Ovidiu Iorga ◽  
Alexandru Marin ◽  
Mihail Munteanu ◽  
...  
Keyword(s):  
Specific Volume ◽  
Adiabatic Calorimeter ◽  
Al Alloy ◽  
Potassium Perchlorate ◽  
Gaseous Products ◽  
Fuel Ratio ◽  
Pyrotechnic Compositions ◽  
Burn Rate ◽  
Input Ratio ◽  
Optimum Input

Pyrotechnic compositions using polyurethane as binder were designed to maximize the temperature of combustion and the burn rate. The flares consisted in mixtures of potassium perchlorate/Mg-Al alloy/polyurethane/additives. In order to determine the optimum input ratio that conducts to the most appropriate solution in terms of theoretical amount of heat released, specific volume of gaseous products and chemical composition, Explo5� thermochemical software runs were executed. Further, the temperature of combustion and the burn rate were determined by infrared thermography, while the heat of combustion and the specific volume of gases were obtained using an adiabatic calorimeter coupled with a Julius-Peters volumeter. The fuel ratio was varied in the compositions in order to optimize the combustion, and the addition of chlorinated rubber confirmed a significant enhancement in both parameters.

Thermal and Impact Sensitivity of Pyrotechnic Compositions Containing the Potassium Perchlorate, Aluminium and Graphite

2019 ◽  
Vol 969 ◽  
pp. 146-151
Author(s):  
K. Harisivasri Phanindra ◽  
S.P. Sivapirakasham ◽  
K.R. Balasubramanian ◽  
Mahadevan Surianarayanan
Keyword(s):  
Thermal Sensitivity ◽  
Exothermic Reaction ◽  
Impact Sensitivity ◽  
Onset Temperature ◽  
Potassium Perchlorate ◽  
Scanning Calorimetry ◽  
Research Article ◽  
Pyrotechnic Compositions ◽  
Pyrotechnic Composition ◽  
The Impact

The research article aims to study the impact and thermal sensitivity of pyrotechnic compositions which contain potassium perchlorate (KClO4), aluminium (Al) and graphite (C). Simultaneous DSC-TGA (Differential Scanning Calorimetry and Thermogravimetric Analysis) were used for studying the thermal sensitivity, and BAM fall hammer was used for studying the impact sensitivity. The onset temperature of the exothermic reaction is between 521°C to 528°C for all the studied compositions. The lowest onset temperature of 521°C and limiting impact energy of 16.67 J were found for the composition containing 64% of potassium perchlorate (KClO4), 33% aluminium (Al) and 3% graphite (C). The highest exothermic energy of 936 J/g was released for pyrotechnic composition consisting of 72% potassium perchlorate (KClO4), 25% aluminium (Al) and 3% graphite (C), which is close to the exothermic energy release of 910 J/g for pyrotechnic composition consisting 64% potassium perchlorate (KClO4), 33% aluminium (Al) and 3% graphite (C). Potassium chloride (KCl) was generated after the exothermic reaction, which was confirmed from the endothermic peak at around 773°C.

Effets of surfaces on precipitate morphology in irradiated thin foils

1978 ◽  
Vol 36 (1) ◽  
pp. 654-655
Author(s):  
D.I. Potter ◽  
A. Taylor
Keyword(s):  
Ion Irradiation ◽  
Dark Field Image ◽  
Thin Foil ◽  
Dark Field ◽  
Al Alloy ◽  
Bright Field Image ◽  
Dislocation Loops ◽  
Precipitate Morphology ◽  
Thin Foils

Thermal aging of Ni-12.8 at. % A1 and Ni-12.7 at. % Si produces spatially homogeneous dispersions of cuboidal γ'-Ni3Al or Ni3Si precipitate particles arrayed in the Ni solid solution. We have used 3.5-MeV 58Ni+ ion irradiation to examine the effect of irradiation during precipitation on precipitate morphology and distribution. The nearness of free surfaces produced unusual morphologies in foils thinned prior to irradiation. These thin-foil effects will be important during in-situ investigations of precipitation in the HVEM. The thin foil results can be interpreted in terms of observations from bulk irradiations which are described first.Figure 1a is a dark field image of the γ' precipitate 5000 Å beneath the surface(∿1200 Å short of peak damage) of the Ni-Al alloy irradiated in bulk form. The inhomogeneous spatial distribution of γ' results from the presence of voids and dislocation loops which can be seen in the bright field image of the same area, Fig. 1b.

A microscopic marker experiment study on high temperature oxidation of Ni-Al alloy

1986 ◽  
Vol 44 ◽  
pp. 514-515
Author(s):  
Shou-kong Fan
Keyword(s):  
Transport Mechanism ◽  
High Temperature Oxidation ◽  
Transverse Section ◽  
Al Alloy ◽  
Metal Interface ◽  
Electron Microscopic ◽  
Temperature Oxidation ◽  
Analytical Electron ◽  
Microscopic Studies ◽  
First Time

Transmission and analytical electron microscopic studies of scale microstructures and microscopic marker experiments have been carried out in order to determine the transport mechanism in the oxidation of Ni-Al alloy. According to the classical theory, the oxidation of nickel takes place by transport of Ni cations across the scale forming new oxide at the scale/gas interface. Any markers deposited on the Ni surface are expected to remain at the scale/metal interface after oxidation. This investigation using TEM transverse section techniques and deposited microscopic markers shows a different result,which indicates that a considerable amount of oxygen was transported inward. This is the first time that such fine-scale markers have been coupled with high resolution characterization instruments such as TEM/STEM to provide detailed information about evolution of oxide scale microstructure.

Diffraction study on bainite of Cu-Al alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 1006-1007
Author(s):  
Delu Liu ◽  
T. Ko
Keyword(s):  
Diffraction Study ◽  
Parent Phase ◽  
Al Alloy ◽  
Alloy Sample ◽  
Bright Field Image ◽  
Hexagonal System ◽  
Iced Brine ◽  
Diffraction Patterns ◽  
Zone Pattern ◽  
Stacking Structure

Structure of bainite in Cu-Al and Cu-Zn-Al alloys has been reported as 3R, 9R or 18R long period stacking structure (LPS) by X-ray and electron diffraction studies. In the present work, a Cu-25.5 (at)% Al alloy sample was heated at 900°C for 2 h then isothermally held at 450°C for 60 s before quenching into iced brine. FIG.1 shows a TEM bright field image of bainite plates (marked B) grown from grain boundary. The parent phase ( with DO3 structure ) has transformed to martensite (marked M ) during cooling from 450° C to 0°C. Both bainite and martensite plates have dense striations inside.Careful diffraction study on a JEOL 2000FX TEM with accelerating voltage 200 KV revealed (FIG.2) that the diffraction patterns contai_ning the same zone axis [001] ( hexagonal index ) or [111]c ( cubic index ) are from a bainite plate with obtuse V-shape. They are indexed as [010], [140], [130], [120], [230], [340] and [110] zone pattern for hexagonal system respectively.

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