Aging of Pyrotechnik Compositions. The investigation of chemical changes by IR spectroscopy and x‐ray diffraction

The physical and chemical characteristics of green signal pyrotechnic mix, before and after destabilization caused by the action of increased humidity at different temperatures, were determined. Data obtained by the means of X‐ray diffraction. IR spectroscopy and adiabatic calorimetry were compared with the results acquired by measuring functional characteristics (the dominant wavelength and the colour hue of the emitted light, the intensity of the emission and the rate of burning). Comparision of all of these results points out to the very close relationship between the X‐ray diffraction data and the function of the signal mix. Chemical changes, leading to the disuse of the examinated mix, were recognized as Mg(OH)2, BaCO3 and Ba(NO2)2 formation with concomittant decrease in Mg and Ba(NO3)2 content. Since no changes were observed in separately aged components, the interaction among components proved to be of essential importance.

Section: Methodssupporting

confidence: 73%

Aging of Pyrotechnic Composition. The reliability of x‐ray diffraction data for estimation of the quality of signal mix

Barišin¹,

Batinić‐Haberle²,

Jovaniáć

1989

“…Ap yrotechnicm ixture is usually composed of one or more oxidizers with one or more reductants (fuels) [1].T he solidstate redox reactionsa ssociated with pyrotechnics mixtures are accompanied with generation of heat, light, or color, which can be applied in emergency signalling, fireworks, gas generator, and special effects devices for the entertainment industry [2][3][4].F or such ac hemical system the ignition temperature is defined as onsett emperature for ar apid, self-propagating reaction between oxidizer and fuel [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Thermoanalytical Investigation of Some Binary Pyrotechnic Mixtures of Ammonium Azide as Chemical Gas Generating Systems

Hosseini

Eslami

2016

The conventional NaN3/oxidants gas generator pyrotechnic mixtures suffer from leaving undesirable solid residues. The presented investigation aimed to overcome this problem through mixing of NH4N3 particles with some metallic components, and to introduce some new gas generator pyrotechnic mixtures. In this work, volatile ammonium azide particles were initially stabilized via microencapsulation technique, and blended with Zr, Ti, ZrH2, and TiH2 powders to produce different gas generation mixtures. Thermal properties and kinetic parameters of these pyrotechnic mixtures were investigated by using thermal analysis (TG/DTA and DSC) techniques. The apparent activation energy (E), ΔG#, ΔH#, ΔS#, and critical ignition temperature (Tb) of the ignition processes of the mixtures were obtained from the DSC experiments. Among the investigated mixtures, NH4N3/ZrH2 composition was found to show desirable efficiency, and also it can be considered as a safe pyrotechnic composition for gas generation property, due to its moderate ignition temperature.

“…Thus, the use of simple, nondestructive, and effective methodologies based on spectroscopic tools such as FTIR and XRD could be interesting. The Batinić‐Haberle research group studied the aging processes of Mg‐PCs using IR and XRD to follow the eventual chemical changes that can occur [17, 18]. The authors proved that artificial aging at higher temperatures and humidity reduces the stability of the pyrotechnic compositions.…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Thermal Aging Behavior of Pyrotechnic Tracer Composition by Spectroscopic Techniques Coupled with Principal Component Analysis

Bekhouche

Chelouche

Abdelaziz

et al. 2021

This work aims to investigate the aging behavior related to heat of a pyrotechnic tracer composition (PTC) sample composed of strontium nitrate as an oxidizer and dual‐fuel of Mg and Mg−Al alloy. Fresh and thermally aged samples were examined using nondestructive spectroscopic techniques, namely Raman spectroscopy, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X‐ray diffraction (XRD). The obtained results showed that aging for 20, 40, and 60 days at 65 °C does not provoke noticeable chemical or structural changes, whereas, after 60 days, the changes are visible, and become more obvious after aging for 120 days. These changes are caused by the partial decomposition of strontium nitrate and the oxidation of magnesium, which are followed by the generation of degradation products such as Sr(NO2)2, MgO, and Mg(OH)2. On the other hand, the applicability of FTIR and XRD associated with a chemometric tool, the principal component analysis, as a simple and useful technique has been also assessed to discriminate the spectra of the aged samples. It has been revealed that these combined approaches can be effectively used to recognize the main compositional and structural changes within the pyrotechnic tracer composition affected by the thermal degradation process.