“…For the DSC results, the heat of reaction is calculated by constructing a tangential-sigmoidal baseline for the exothermic peak in the reaction temperature range for each sample. Dynamic calculations for combustion of the pyrotechnic delay were performed using AKTS-thermokinetics software 10 .Figure 6DSC curves for a pyrotechnic delay according to moisture-induced ageing. An exothermic peak due to the reaction between fuel and oxidant is observed at 325–550 °C.…”
Section: Resultsmentioning
confidence: 99%
“…A variety of ageing studies have recently been conducted on metal fuel/oxidant pyrotechnic materials 10–18 . Here, moisture is a factor that can cause ageing of pyrotechnic materials.…”
The degradation of thermal properties due to ageing such as burning rate and exothermic heat release are unsolved issues faced during a long-term storage of the pyrotechnic substances. Accordingly, we employed various non-calorimetric methods to investigate the thermal performance of pyrotechnic delay, which is exposed to various moisture-rich conditions at extended durations. The chemical and physical changes in the compositions of a pyrotechnic delay comprised of metal fuel (Zr-Ni alloy) and oxidants (KClO4, BaCrO4) are analysed for four different relative humidity levels using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope and laser-induced breakdown spectroscopy. The calculations using the NASA Chemical Equilibrium with Applications (CEA) software indicated that the heat of reaction for the components stored under the moisture-rich conditions is reduced by more than 50%. Unlike the conventional calorimetric analysis, the present non-calorimetric approach provided the compositional changes as well as the cause and effect of the relevant ageing process of pyrotechnic delay.
“…For the DSC results, the heat of reaction is calculated by constructing a tangential-sigmoidal baseline for the exothermic peak in the reaction temperature range for each sample. Dynamic calculations for combustion of the pyrotechnic delay were performed using AKTS-thermokinetics software 10 .Figure 6DSC curves for a pyrotechnic delay according to moisture-induced ageing. An exothermic peak due to the reaction between fuel and oxidant is observed at 325–550 °C.…”
Section: Resultsmentioning
confidence: 99%
“…A variety of ageing studies have recently been conducted on metal fuel/oxidant pyrotechnic materials 10–18 . Here, moisture is a factor that can cause ageing of pyrotechnic materials.…”
The degradation of thermal properties due to ageing such as burning rate and exothermic heat release are unsolved issues faced during a long-term storage of the pyrotechnic substances. Accordingly, we employed various non-calorimetric methods to investigate the thermal performance of pyrotechnic delay, which is exposed to various moisture-rich conditions at extended durations. The chemical and physical changes in the compositions of a pyrotechnic delay comprised of metal fuel (Zr-Ni alloy) and oxidants (KClO4, BaCrO4) are analysed for four different relative humidity levels using X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope and laser-induced breakdown spectroscopy. The calculations using the NASA Chemical Equilibrium with Applications (CEA) software indicated that the heat of reaction for the components stored under the moisture-rich conditions is reduced by more than 50%. Unlike the conventional calorimetric analysis, the present non-calorimetric approach provided the compositional changes as well as the cause and effect of the relevant ageing process of pyrotechnic delay.
“…The DSC thermograms were also used to calculate the heat of reaction ∆H using Advanced Kinetics and Technology Solutions (AKTS) software 5 , utilising a sigmoidal tangential baseline to identify the initial and final heat flow changes. Table S1 and Fig.…”
Section: Resultsmentioning
confidence: 99%
“…The activation energy, E α values were calculated using AKTS 5 based on two different isoconversional methods (the Friedman 33 and Ozawa 34 methods), which adhere to the isoconversional principle 33–35 . The intrinsic error stemmed from high sensitivity to noise of Friedman method may give rise to a large deviation in the kinetic parameters.…”
Ageing of pyrotechnic substance, primarily fuel oxidisation, can cause changes in composition that degrade their performance. This study investigates the effect of ageing on zirconium potassium perchlorate (ZPP), a widely used NASA Standard Initiator. Although prior studies have investigated the effects of accelerated ageing on ZPP, this is the first to conduct kinetic analyses at different relative humidity (RH) levels. Here, both thermal and kinetic analyses are conducted for a variety of hygrothermal ageing cases in order to replicate the natural ageing process. X-ray photoelectron spectroscopy (XPS) results reveal that oxidant levels drop and zirconium dioxide levels rise as ZPP ages. Lower heats of reaction and increases in activation energy were also observed under the RH conditions. Calculations using van’t Hoff equation indicate that moisture shortened the lifespan of the unaged ZPP up to about 85% under extreme RH conditions, while significantly deteriorating the heat of reaction, sensitivity, and thus increased the risk of a misfire.
“…Each of these experimental techniques has its different characteristics and requires a small amount of sample for reliable data acquisition which serves the safety of operation. These techniques have also been proven to be good tools for monitoring the ageing process of energetic compounds [21] and their formulations, including Composition B. In the present work, we propose to investigate the effect of the natural ageing process on the thermal properties of Composition B, which has been stored in the casing for 20 and 32 y under natural environmental conditions.…”
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