Qualification of Magnesium/Teflon/Viton Pyrotechnic Composition Used in Rocket Motors Ignition System

Barros, Luciana de Amorim; Pinheiro, Afonso Paulo Monteiro; Câmara, Josemar da Encarnação; Iha, Koshun

doi:10.5028/jatm.v8i2.596

Cited by 14 publications

(5 citation statements)

References 4 publications

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“…The maximum gas release required by the MIL-STD-1751A standard is 2 mL g À 1 . The gas volume released in this test is a valid measure of the material stability [20].…”

Section: Stability Testmentioning

confidence: 99%

Preparation and Characterization of Pour‐Casting Red Phosphorus Smoke Agents with HTPB as Binder

Yang

Tseng

et al. 2021

Propellants Explo Pyrotec

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The main aim of this study is to develop the vacuum pour‐casting process of the red phosphorus smoke agents. The typical composition of MK 58 marine location marker prepared by tamp‐casting process is red phosphorus (RP)/magnesium (Mg)/manganese dioxide (MnO2)/zinc oxide (ZnO)/epoxy resin (ER), which was selected as the original formula. Epoxy resin (ER) was replaced by hydroxyl terminated polybutadiene (HTPB) as the binder. First of all, simultaneous differential scanning calorimetry‐thermogravimetric analysis (STA DSC‐TGA) and vacuum stability tester (VST) were used to analyze the thermochemical characteristics, stability and chemical compatibility of the formula. Afterwards, Taguchi's experimental design method was used to design nine experimental conditions by way of orthogonal array with four control factors and three levels, and the scaled‐down smoke pellets were prepared using the vacuum pour‐casting method. The combustion phenomenon of these smoke pellets was recorded by the visual‐image capture system, and the flame temperature was measured by the temperature measurement system. The burning rate was chosen as the quality characteristic to analyze the optimal parameter combination of minimum burning rate. In addition, scanning electron microscopy coupled with energy dispersive spectroscopy (SEM‐EDS), tensile testing machine (TTM) and hardness tester (HT) were employed to observe the uniformity of the composition distribution in the pellet and to measure the mechanical strength and hardness of the pellets. Smoke density test chamber (SDTC) was used to measure the specific optical density of smoke generated by RP smoke agent. Finally, the operating conditions of the optimal parameter combination determined by Taguchi method were used to prepare the full‐size smoke candle, and its burning performance was verified and the feasibility of the vacuum pour‐casting technology was evaluated. The experimental results indicated that the optimal combination of parameters was the RP mixture/HTPB mass ratio of 84 : 16, the NCO/OH ratio of IPDI to HTPB (R value) of 1.6, the additional DOA of 4.5 wt % and the curing temperature of 50 °C. The prepared scaled‐down smoke pellets had good stability, chemical compatibility, hardness, mechanical properties and burning smoke density. In addition, the burning time and performance of the full‐size smoke candles prepared by vacuum pour‐casting technology also met the requirements.

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“…The maximum gas release required by the MIL-STD-1751A standard is 2 mL g À 1 . The gas volume released in this test is a valid measure of the material stability [20].…”

Section: Stability Testmentioning

confidence: 99%

Preparation and Characterization of Pour‐Casting Red Phosphorus Smoke Agents with HTPB as Binder

Yang

Tseng

et al. 2021

Propellants Explo Pyrotec

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“…The boron particles start burning when the molten oxide evaporates from their surface [20][21][22]. Recently, fluorinated polymers have significantly improved the combustion efficiency of boron [15,[23][24][25]. The inclusion of fluorine in boron-based solid fuels promotes the gasification process of boron oxide and enhances the removal of the molten oxide layer.…”

Section: Introductionmentioning

confidence: 99%

“…The pure HTPB fuel formulation was prepared using a vacuum casting technique, and performance characteristics were compared with HTPB-PTFE and HTPB-PTFE-B 4 C-based solid fuels. The regression rates of prepared solid fuels were investigated using an opposed flow burner (OFB) setup under gaseous oxygen as an oxidizer [25,[31][32]. A combustion mechanism has been proposed based on OFB experiments in order to provide insight into the various oxidation reactions involved during combustion.…”

Section: Introductionmentioning

confidence: 99%

Exploring the potential of boron carbide in enhancing energy output of solid fuels for SFRJ and hybrid rocket propulsion systems

Nithya Mahottamananda,

Pal,

Alay Hashim

et al. 2023

Propellants Explo Pyrotec

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Boron carbide (B4C) is known for its exceptional hardness and high energy release during combustion, despite its ignition processes presents considerable challenges. This study focuses on exploring the potential of B4C as an enhancer for the energy output of solid fuels designed for hybrid rocket engines (HRE) or solid fuel ramjets (SFRJ). This study presents the successful incorporation of B4C and fluorinated PTFE (polytetrafluoroethylene) polymer into the HTPB (hydroxyl‐terminated polybutadiene) fuel matrix, aiming to enhance the ignition, combustion, and regression rate performance of solid fuel. Five different fuel compositions were formulated with varying mass ratios of B4C, and their post‐combustion products were characterized using XRD (X‐ray diffraction), HRSEM (high‐resolution scanning electron microscopy), and EDS (energy‐dispersive X‐ray spectroscopy) techniques. The HRSEM‐EDS analysis confirmed a uniform dispersion of B4C/PTFE additives throughout the HTPB matrix. To evaluate the combustion behavior of the B4C/PTFE additives, an opposite flow burner was employed with a gaseous oxygen oxidizer. The F4 fuel sample, loaded with B4C/PTFE (10/20), exhibited an average regression rate increase ranging from 0.61 to 1.15 mm/s when evaluated within the oxidizer flux range of 36–77 kg/m2s, in comparison to that of pure HTPB (0.4 mm/s to 0.76 mm/s). The ignition delay time was investigated as a key parameter affected by the B4C concentration in the solid fuel formulations. Furthermore, a comprehensive combustion mechanism is proposed and discussed for B4C/PTFE loaded in the HTPB matrix under an oxygen environment.

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“…Fluoroelastomers such as Viton are used in synchrony with release agents and fusing oils [ 14 , 15 , 16 ]. Viton (dipolymers of hexafluoropropylene and vinylidene fluoride) is a fluorine-rich polymer with low melting point and plasticity, which imparts the mechanical and electrical integrity of the composites [ 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

Volume Resistivity of Viton Polymer under Thermal Aging

2021

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This study examines the influence of various electrical parameters on the volume resistivity of the Viton fluoroelastomer. The transient current, the temperature dependence of volume resistivity, the voltage dependence of resistivity, and the surface morphology of Viton insulators are investigated for new and aged specimens. An accelerated aging process has been employed in order to simulate the natural aging of insulators in service. A detailed comparison between the new and aged samples is presented. The transient effect, which is a challenge to the resistivity measurement of insulators, has been investigated. The first 60 s of the resistivity measurement test showed a significant influence from the transient effect and should be excluded from the data. The volume resistivity of both new and aged samples decreased when the temperature increased. However, the resistivity of the aged sample was lower than the new one at all tested temperatures. When the temperature increased from 35 to 190 °C, resistivity decreased from 4.77 × 1010 to 6.99 × 108 Ω-cm for the new sample and from 2.6 × 1010 to 6.68 × 108 Ω-cm for the aged sample under 500 V. Additionally, the results from this study showed that the volume resistivity is inversely proportional to the applied voltage. Finally, scanning electron microscope (SEM) micrographs/images allowed us to closely examine the surface morphology of new and aged Viton samples. The surface of aged samples has been recognized with higher surface roughness and more significant surface cracks leading to poor performance under high voltage applications.

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Qualification of Magnesium/Teflon/Viton Pyrotechnic Composition Used in Rocket Motors Ignition System

Cited by 14 publications

References 4 publications

Preparation and Characterization of Pour‐Casting Red Phosphorus Smoke Agents with HTPB as Binder

Preparation and Characterization of Pour‐Casting Red Phosphorus Smoke Agents with HTPB as Binder

Exploring the potential of boron carbide in enhancing energy output of solid fuels for SFRJ and hybrid rocket propulsion systems

Volume Resistivity of Viton Polymer under Thermal Aging

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