Thermochemical Ablation of Ceramic Heat Shields

Ziering, M.

doi:10.2514/3.49773

Cited by 10 publications

(1 citation statement)

References 4 publications

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“…In the work, the as-received composite is composed of Si 3 N 4 and BN [3] which have not the melting point. For example, Si 3 N 4 decomposes at 1900°C [5], and BN sublimates at 3000°C. Especially for BN, the sublimation heat is 55816kJ/kg [6], which is 4.39 times higher than that of silica [2].…”

Section: Resultsmentioning

confidence: 99%

Ablation Performance and Surface Texture of the Nitride Composites Reinforced by the Braided Silica Fibers

Jiang

Zhang

Cao

et al. 2008

KEM

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Braided silica fibers reinforced nitride composite (SFRN), which was prepared by the polymeric precursor infiltration and pyrolysis (PIP) process with the precursor polyborosilazane (PSBZ), was a new typed microwave transparent material with high mechanical and ablation resistance performance for high-temperature application. The thermal ablation performance of the SFRN was evaluated by the ablation equipment with the kerosene and liquid oxygen as the heating source. The ablation surface texture of the SFRN including macrostructure and roughness were measured by Three-dimensional Macrostructure and Contour Scale System (TMCSS). Results showed that there are no concurrent observation of thermal delaminations or cracks and the specimen remains intact. The SFRN has an excellent thermal shock resistance and good ablation resistance with the linear recession rate of 0.038mm/s. The ablation surface texture of the SFRN can be well illuminated by the TMCSS. And the ablation performance will be improved by enhancing material density and homogeneous intertextures.

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Section: Resultsmentioning

confidence: 99%

Ablation Performance and Surface Texture of the Nitride Composites Reinforced by the Braided Silica Fibers

Jiang

Zhang

Cao

et al. 2008

KEM

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Ablation Property and Mechanism of Nitride‐Based Ceramic Composites Reinforced by Braided Silica Fibers

et al. 2007

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It is well known that vehicles traveling with high speed excite the air to high temperature, then air is ionized and the asreceived plasma gas forms on the boundary layer. The nosetip material will be ablated by the aero-heating air, such as fused, decomposition, sublimation or chemical reactions. [1] Furthermore, the dielectric properties of one material will change with the increasing temperature, which has an effect on the radar-wave transmission characters. [2] So a radar window for a supersonic vehicle should process critical property, such as a high resistance to stress failure induced by large thermal load and a high ablation resistance. In our previous work, [3] the 2.5 dimensional silica fibers reinforced the nitride-based composites (2.5D SiO 2f /Si 3 N 4 -BN) were prepared by preceramic polymer impregnation and pyrolysis (PIP) method through repeated infiltration of hybrid precursor polyborosilazane (PBSZ). Results showed that the composites had an excellent mechanical, dielectric and ablation properties. In this paper, the ablation property and ablation mechanism under an arc-jet stream were investigated. Experimental Procedures Composites PreparationAccording to literature, [3] PBSZ was used to infiltrate 3-dimensional silica fiber fabric (3D SiO 2f ), the 3D-SiO 2f reinforced nitride-based composites (3D-SRNC) were prepared by PIP method. The silica fibers, produced by JingZhou Feilihua Silica Glass Corporation (China), have a diameter of 6 ∼ 8 lm, a density of 2.2 g/cm 3 , a room temperature tensile strength of 1 700 MPa and an elastic modulus of 78 GPa. To form a 3D-braided silica fiber fabric, with the fiber volume fraction 50 %, those fabrics were woven by Beijing Fiberglass Research & Design Institute (China). The infiltration-curepyrolysis cycles were repeated for five times and then the density of the 3D-SRNC reaches 1.71 ∼ 1.74 g/cm 3 . CharacterizationSpecimens with the dimension size 30 × 40 mm were characterized using an arc-jet stream ablation tester. Ablation temperature was above 4500°C and ablation time was 10 s. The average mass loss rate (defined as the weight loss per unit time) and linear ablation rate (defined as the thickness loss per unit time) of the specimens were measured after the ablation test. Scanning electron microscopy (SEM, JSM-5600LV) was used to observe the ablation surfaces morphology. Energy-dispersive X-ray spectroscopy (EDS) was carried

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High-Temperature Environment and Composite Materials

Dimitrienko

2016

Thermomechanics of Composite Structures Under High Temperatures

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Thermochemical Ablation of Ceramic Heat Shields

Cited by 10 publications

References 4 publications

Ablation Performance and Surface Texture of the Nitride Composites Reinforced by the Braided Silica Fibers

Ablation Performance and Surface Texture of the Nitride Composites Reinforced by the Braided Silica Fibers

Ablation Property and Mechanism of Nitride‐Based Ceramic Composites Reinforced by Braided Silica Fibers

High-Temperature Environment and Composite Materials

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