scholarly journals Effects of Zirconium Silicide on the Vulcanization, Mechanical and Ablation Resistance Properties of Ceramifiable Silicone Rubber Composites

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 496 ◽  
Author(s):  
Jiuqiang Song ◽  
Zhixiong Huang ◽  
Yan Qin ◽  
Honghua Wang ◽  
Minxian Shi
Keyword(s):  
Thermal Conductivity ◽  
Silicone Rubber ◽  
Thermal Protection ◽  
Permanent Deformation ◽  
Ablation Rate ◽  
Decomposition Temperature ◽  
Rubber Composites ◽  
Initial Decomposition Temperature ◽  
Ablation Resistance ◽  
Zirconium Silicide

Ceramifiable silicone rubber composites play important roles in the field of thermal protection systems (TPS) for rocket motor cases due to their advantages. Ceramifiable silicone rubber composites filled with different contents of ZrSi2 were prepared in this paper. The fffects of ZrSi2 on the vulcanization, mechanical and ablation resistance properties of the composites were also investigated. The results showed that the introduction of ZrSi2 decreased the vulcanization time of silicone rubber. FTIR spectra showed that ZrSi2 did not participate in reactions of the functional groups of silicone rubber. With the increasing content of ZrSi2, the tensile strength increased first and then decreased. The elongation at break decreased and the permanent deformation increased gradually. The thermal conductivity of the composite increased from 0.553 W/(m·K) to 0.694 W/(m·K) as the content of the ZrSi2 increased from 0 to 40 phr. In addition, the thermal conductivity of the composite decreased with the increase of temperature. Moreover, thermal analysis showed that the addition of ZrSi2 increased the initial decomposition temperature of the composite, but had little effect on the peak decomposition temperature in nitrogen. However, the thermal decomposition temperature of the composite in air was lower than that in nitrogen. The addition of ZrSi2 decreased the linear and mass ablation rate, which improved the ablative resistance of the composite. With the ZrSi2 content of 30 phr, the linear and mass ablation rate were 0.041 mm/s and 0.029 g/s, decreasing by 57.5% and 46.3% compared with the composite without ZrSi2, respectively. Consequently, the ceramifiable silicone rubber composite filled with ZrSi2 is very promising for TPS.

scholarly journals Preparation and Properties of C/SiC Composites Reinforced by High Thermal Conductivity Graphite Films

2020 ◽  
Author(s):  
Jiajia Zhao ◽  
Rong Cai ◽  
zhaokun Ma ◽  
Kaixuan Zhang ◽  
Hengliang Liang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Mass Loss Rate ◽  
Ceramic Matrix Composites ◽  
Ablation Rate ◽  
High Thermal Conductivity ◽  
Matrix Composites ◽  
Ablation Resistance ◽  
Linear Ablation ◽  
Graphite Film ◽  
Sic Composites

Abstract Ablation resistance as one important factor affecting the service life of SiC ceramic matrix composites that is highly valued in aerospace science and technology. In this study, high thermal conductivity (HTC) graphite films and carbon fibers reinforced C/SiC composites simultaneously, fabricating by precursor infiltration and pyrolysis (PIP) technology, to improve the ablation resistance of C/SiC composites. Three C/SiC composites were prepared from different quantity ratios of 2D fiber cloth to HTC graphite film with values of 1:0, 1:1, and 1:10. The microstructure, mechanical properties, thermal conductivity and ablation performance of C/SiC composites after plasma ablation test at 1500 °C for 600 s were investigated. The results showed that with the increase of graphite films’ contents, the thermal conductivity of composites was increased from 9.78 W/(m·K) to 333.34 W/(m·K). Additionally, the mass loss rate reduced from 1.18 to 0.74 mg/s and the linear ablation rate reduced from 0.64 to 0.18 mm/s, indicating that the addition of graphite films could effectively improve the ablation resistance of C/SiC composites.

scholarly journals Ablation Behavior of a Carbon Fabric Reinforced Phenolic Composite Modified by Surface-Decorated ZrB2/SiC

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 256 ◽  
Author(s):  
Feng Xu ◽  
Shizhen Zhu ◽  
Jingdan Hu ◽  
Zhuang Ma ◽  
Yanbo Liu
Keyword(s):  
Heat Dissipation ◽  
Mechanical Performance ◽  
Thermal Protection ◽  
Ablation Rate ◽  
Carbon Fabric ◽  
Good Surface ◽  
Sic Particles ◽  
Ablation Resistance ◽  
Service Environments ◽  
Phenolic Composite

Carbon fabric reinforced phenolic composites were widely used as TPSs (thermal protection system) material in the aerospace industry. However, their limited oxidative ablation resistance restricted their further utility in more serious service conditions. In this study, the surface-decorated ZrB2/SiC and its modified carbon fabric reinforced phenolic composites have been successfully prepared. The self-modification mechanism of the surface-decorated ZrB2/SiC particles were characterized. The mechanical performance and ablation behavior of the composites were investigated. Results showed that the ZrB2/SiC particles possessed a good surface-decorated effect, which achieved good compatibility with the phenolic resin. The mechanical performance of the modified phenolic composite was effectively improved. The anti-oxidative ablation performance of the composite was improved. The mass ablation rate of the surface-decorated ZrB2–SiC-modified carbon fabric reinforced phenolic composites was 25% lower than that of the unmodified composites. The formed ZrO2 ceramic layer attached to the surface of the residual chars prevented the heat energy and oxygen from the inner material. Meanwhile, the volatilization of SiO2 and B2O3 effectively increased the heat dissipation. All these results confirmed that the ZrB2–SiC particles can effectively improve the ablation resistance of the composite, which provided a basis for the application of the composites to more serious service environments.

scholarly journals Ablation Behavior of the SiC-Coated Three-Dimensional Highly Thermal Conductive Mesophase-Pitch-Based Carbon-Fiber-Reinforced Carbon Matrix Composite under Plasma Flame

Materials ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 2723
Author(s):  
Chong Ye ◽  
Dong Huang ◽  
Baoliu Li ◽  
Pingjun Yang ◽  
Jinshui Liu ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Thermal Protection ◽  
Three Dimensional ◽  
Chemical Vapor ◽  
Carbon Matrix ◽  
Ablation Rate ◽  
Chemical Vapor Infiltration ◽  
Mesophase Pitch ◽  
Plasma Flame ◽  
Ablation Resistance

This study is focused on a novel high-thermal-conductive C/C composite used in heat-redistribution thermal protection systems. The 3D mesophase pitch-based carbon fiber (CFMP) preform was prepared using CFMP in the X (Y) direction and polyacrylonitrile carbon fiber (CFPAN) in the Z direction. After the preform was densified by chemical vapor infiltration (CVI) and polymer infiltration and pyrolysis (PIP), the 3D high-thermal-conductive C/C (CMP/C) composite was obtained. The prepared CMP/C composite has higher thermal conduction in the X and Y directions. After an ablation test, the CFPAN becomes needle-shaped, while the CFMP shows a wedge shape. The fiber/matrix and matrix/matrix interfaces are preferentially oxidized and damaged during ablation. After being coated by SiC coating, the thermal conductivity plays a significant role in decreasing the hot-side temperature and protecting the SiC coating from erosion by flame. The SiC-coated CMP/C composite has better ablation resistance than the SiC-coated CPAN/C composite. The mass ablation rate of the sample is 0.19 mg·(cm−2·s−1), and the linear ablation rate is 0.52 μm·s−1.

scholarly journals Synergistic Effects of Functional CNTs and h-BN on Enhanced Thermal Conductivity of Epoxy/Cyanate Matrix Composites

Nanomaterials ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 997 ◽  
Author(s):  
Mingzhen Xu ◽  
Yangxue Lei ◽  
Dengxun Ren ◽  
Sijing Chen ◽  
Lin Chen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermal Conductivity Coefficient ◽  
Hexagonal Boron Nitride ◽  
Synergistic Effects ◽  
Decomposition Temperature ◽  
Resin Matrix ◽  
Matrix Composites ◽  
Initial Decomposition Temperature ◽  
Microelectronic Devices ◽  
Enhanced Thermal Conductivity

Epoxy/cyanate resin matrix composites (AG80/CE) with improved thermal conductivity and mechanical properties were obtained with synergetic enhancement with functional carbon nanotubes (f-CNTs) and hexagonal boron nitride (h-BN). AG80/CE performed as polymeric matrix and h-BN as conductivity filler which formed the main thermal conductivity channels. Small amounts of f-CNTs were introduced to repair defects in conductivity channels and networks. To confirm the synergetic enhancements, the thermal conductivity was investigated and analyzed with Agari’s model. Results indicated that with introduction of 0.5 wt% f-CNTs, the thermal conductivity coefficient (ƛ) increased to 0.745 W/mk, which is 1.38 times that of composites with just h-BN. Furthermore, the flexural strength and modulus of composites with 0.5 wt% f-CNTs were 85 MPa and 3.5 GPa. The glass transition temperature (Tg) of composites with 0.4 wt% was 285 °C and the initial decomposition temperature (T5%) was 385 °C, indicating outstanding thermal stability. The obtained h-BN/f-CNTs reinforced AG80/CE composites present great potential for packaging continuous integration and miniaturization of microelectronic devices.

scholarly journals Improved Ablation Resistance of Silicone Rubber Composites by Introducing Montmorillonite and Silicon Carbide Whisker

Materials ◽  
2016 ◽  
Vol 9 (9) ◽  
pp. 723 ◽  
Author(s):  
Guangwu Zhang ◽  
Fuzhong Wang ◽  
Zhixiong Huang ◽  
Jing Dai ◽  
Minxian Shi
Keyword(s):  
Silicon Carbide ◽  
Silicone Rubber ◽  
Rubber Composites ◽  
Silicon Carbide Whisker ◽  
Ablation Resistance

Research on Thermal Aging Characteristics and Mechanism of the Silicon Rubber Insulation Layer of Cable Joints

2019 ◽  
Vol 960 ◽  
pp. 161-166 ◽  
Author(s):  
Yong Lan Li ◽  
Man Shi Qiu ◽  
Jia Wei Ma ◽  
Guo Wen Kuang ◽  
Nai Kui Gao ◽  
...  
Keyword(s):  
Mass Loss ◽  
Silicone Rubber ◽  
Thermal Aging ◽  
Mass Loss Rate ◽  
Chain Structure ◽  
Decomposition Temperature ◽  
Insulation Layer ◽  
Initial Decomposition Temperature ◽  
Theoretical Support ◽  
Degradation Reaction

In order to solve the thermal aging problem of silicone rubber insulation layer of 220 kV integral prefabricated cable joints, the mass loss and thermal gravimetric (TG) were tested. The thermal aging mechanism of thermal degradation reaction of silicone rubber molecular chains was analyzed by gel content test and infrared spectrum test (IR). The results showed that the cross-linked network of the molecular chain structure gradually deteriorates, resulting in the increase of mass loss rate and the decrease of thermal stability. The results also showed that the increase of dual peak of differential thermal weight (DTG), the decrease of initial decomposition temperature and the remaining mass. With increasing aging temperature and aging time, the aging would be accelerated. These properties could reflect the degree of thermal aging of silicone rubber insulation layer. The results could also provide theoretical support for the preparation, operation and maintenance for silicone rubber cable joints.

Study on the thermal stability and ablation properties of metallic oxide-filled silicone rubber composites using uniform design method

2016 ◽  
Vol 36 (8) ◽  
pp. 805-811 ◽  
Author(s):  
Rui Li ◽  
Cheng Zhou ◽  
Lin Yu ◽  
Yang Chen ◽  
Huawei Zou ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Silicone Rubber ◽  
Design Method ◽  
Uniform Design ◽  
Ablation Process ◽  
Rubber Composites ◽  
Metallic Oxide ◽  
Ablation Resistance ◽  
Uniform Design Method ◽  
Thermal Stability Property

Abstract The thermal stability and ablation properties of silicone rubber composites filled with Fe2O3, SnO2, CuO, MgO, and Al2O3 were researched using thermogravimetric analysis (TGA) and the oxyacetylene torch test. The effecting laws of metallic oxide on the thermal stability and ablation properties of silicone rubber composites were analyzed by uniform design method. TGA indicated that the thermal degradation process of silicone rubber composites took a two mass loss steps. The effecting order of metallic oxide on enhancing thermal stability property of silicone rubber composites in step 1 was MgO>SnO2> Fe2O3>Al2O3>CuO, whereas the order in step 2 was CuO> SnO2>MgO>Fe2O3>Al2O3. Furthermore, Fe2O3 and SnO2 had an evident synergistic effect on enhancing the thermal stability property and residual carbon of silicone rubber composites. The oxyacetylene torch test showed that the effecting order of metallic oxide on increasing ablation resistance property of silicone rubber composites in ablation process was CuO>MgO>Fe2O3>SnO2>Al2O3. Moreover, the line ablation rate of specimen 2 was 0.0499, which indicated that it had the best ablation resistance among all uniform samples. Furthermore, scanning electron microscopy also showed that the porous ceramic layer became much denser after the ablation process, and this will significantly improve the ablation resistance property.

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