scholarly journals SiC-Coated Carbon Nanotubes with Enhanced Oxidation Resistance and Stable Dielectric Properties

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2770
Author(s):  
Rong Li ◽  
Yuchang Qing ◽  
Juanjuan Zhao ◽  
Shiwen Huang
Keyword(s):  
Carbon Nanotubes ◽  
High Temperature ◽  
Dielectric Properties ◽  
Oxidation Resistance ◽  
Pyrolysis Temperature ◽  
X Band ◽  
Pristine Cnts ◽  
Long Time ◽  
Sic Composites ◽  
Coated Carbon

Carbon nanotubes (CNTs) coated with SiC coating was successfully prepared by pyrolysis of polycarbosilane (PCS) used as a precursor. The function of pyrolysis temperature on the oxidation resistance and the dielectric properties of CNTs/SiC were studied in X-band. The results demonstrate that the obtained dense SiC film can prevent the oxidation of CNTs when the pyrolysis temperature reaches 600 °C. Correspondingly, after heat treatment is at 400 °C for 200 h, the mass loss of P-600 is less than 1.86%, and the real and imaginary parts of the dielectric constant nearly keep constant (ε′ from 14.2 to 14, and ε″ from 5.7 to 5.5). SiC-coated CNTs have a better oxidation resistance than pristine CNTs. Therefore, this work, with a facile preparation process, enhances the oxidation resistance of CNTs at high temperature for a long time and maintains a stable dielectric property, which means CNTs/SiC composites can be good candidates for applications in the field of high-temperature absorbers.

Experimental Analysis and Material Characterization of Ultra High Temperature Composites

2021 ◽  
Author(s):  
Anindya Ghoshal ◽  
Michael J. Walock ◽  
Andy Nieto ◽  
Muthuvel Murugan ◽  
Clara Hofmeister-Mock ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Material Characterization ◽  
High Energy ◽  
Test Material ◽  
Layer System ◽  
Vannevar Bush ◽  
Sic Composites ◽  
Ultra High Temperature

Abstract Ultra high temperature ceramic (UHTC) materials have attracted attention for hypersonic applications. Currently there is significant interest in possible gas turbine engine applications of UHTC composites as well. However, many of these materials, such as hafnium carbide, zirconium carbide, and zirconium diboride, have significant oxidation resistance and toughness limitations. In addition, these materials are very difficult to manufacture because of their high melting points. In many cases, SiC powder is incorporated into UHTCs to aid in processing and to enhance fracture toughness. This can also improve the materials’ oxidation resistance at moderately high temperatures due to a crack-healing borosilicate phase. ZrB2-SiC composites show very good oxidation resistance up to 1700 °C, due to the formation of SiO2 and ZrO2 scales in numerous prior studies. While this may limit its application to hypersonic applications (due to reduced thermal conductivity and oxidation resistance at higher temperatures), these UHTC-SiC composites may find applications in turbomachinery, as either stand-alone parts or as a component in a multi-layer system. The US Army Research Laboratory (ARL), the Naval Postgraduate School (NPS), and the University of California – San Diego (UCSD) are developing tough UHTC composites with high durability and oxidation resistance. For this paper, UHTC-SiC composites and high-entropy fluorite oxides were developed using planetary and high-energy ball milling and consolidated using spark plasma sintering. These materials were evaluated for their oxidation-resistance, ablation-resistance, and thermal cycling behavior under a DoD/OSD-funded Laboratory University Collaborative Initiative (LUCI) Fellowship and DoD Vannevar Bush Fellowship Program. In the present paper experimental results and post-test material characterization of SPS sintered ZrB2, ZrB2+SiC, ZrB2+SiC+HfC, HfC+SiC, and HfC+ZrB2 pellets subjected to ablation test are presented.

High-temperature oxidation resistance of Si-coated C/SiC composites

Rare Metals ◽  
2019 ◽  
Author(s):  
Jie Xiao ◽  
Hua-Yue Zhang ◽  
Sheng-Kai Gong ◽  
Hui-Bin Xu ◽  
Hong-Bo Guo
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Sic Composites

Pyramid Shaped Pyrolysis Flame Catalyst Synthesis of Carbon Nanotubes

2010 ◽  
Vol 177 ◽  
pp. 421-426 ◽  
Author(s):  
Zhao Yong Ding ◽  
Bao Min Sun ◽  
Yuan Chao Liu ◽  
Bing Hao Xu ◽  
Yong Hong Guo
Keyword(s):  
Carbon Nanotubes ◽  
High Temperature ◽  
Pyrolysis Temperature ◽  
Synthesis Temperature ◽  
Iron Pentacarbonyl ◽  
Sampling Time ◽  
Thermal Dissipation ◽  
Synthesis Process ◽  
Initial Reaction ◽  
Catalyst Precursor

Pyramid sharped pyrolysis flame is a new method for carbon nanotubes synthesis. Oxy-acetylene flame outside the frustum of pyramid sharped reactor provides the necessary high temperature environment, while CO is used as the source of carbon, iron pentacarbonyl (Fe(CO)5) as the source of catalyst precursor in reactor. Inside, the mixture of CO, H2, and Fe(CO)5 will burn incompletely after initial reaction under high temperature. Immerging a sampling substrate into the incomplete burning flame can gain carbon nanotubes. Field emission scanning electron microscope and High resolution transmission electron microscopy were used to illustrate the results of experimental. By adjusting the distance between the oxy-acetylene flame jet and the synthesis zone, the purpose that only changing one factor of synthesis or pyrolysis temperature while the other one constant was achieved, then respectively studied the effects of them on experimental. The best synthesis temperature in experimental is about 590°C and pyrolysis temperature is about 1000°C. Effects of sampling time were also studied. 300s is economic for carbon nanotubes synthesis. Synthesis process of carbon nanotubes was discussed starting from the sampling time. The first 60s is the time for the temperature rise of sampling substrate. After the decalescence and thermal dissipation of substrate is balance, the temperature of substrate is fixed, and the main synthesis phase of carbon nanotubes begin.

Effect of residual silicon on the oxidation resistance of bilayer Yb2Si2O7/SiC coated C/SiC composites at high temperature

2020 ◽  
Vol 170 ◽  
pp. 108676
Author(s):  
Pengju Chen ◽  
Peng Xiao ◽  
Zhuan Li ◽  
Jinwei Li ◽  
Dongmei Pu ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Sic Composites

Conversion of Nickel Coated Carbon Nanotubes to Diamond under High Pressure and High Temperature

1998 ◽  
Vol 37 (Part 2, No. 9A/B) ◽  
pp. L1085-L1086 ◽  
Author(s):  
Weiqiang Han ◽  
Shoushan Fan ◽  
Qunqing Li ◽  
Chuan Lin Zhang
Keyword(s):  
Carbon Nanotubes ◽  
High Pressure ◽  
High Temperature ◽  
Coated Carbon

Fluoro-polymer-coated carbon nanotubes for improved interfacial interactions and dielectric properties in MWCNTs/PVDF composites

2019 ◽  
Vol 55 (8) ◽  
pp. 3212-3227 ◽  
Author(s):  
Shixin Song ◽  
Shan Xia ◽  
Yingcong Wei ◽  
Xue Lv ◽  
Shulin Sun ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Dielectric Properties ◽  
Interfacial Interactions ◽  
Coated Carbon

Electrically Conductive Oxidation-Resistant Boron-Coated Carbon Nanotubes Derived from Atmospheric CO2 for Use at High Temperature

2020 ◽  
Vol 3 (9) ◽  
pp. 8592-8597
Author(s):  
Gi Mihn Kim ◽  
Won Yeong Choi ◽  
Jae Hyun Park ◽  
Seung Jin Jeong ◽  
Jong-Eun Hong ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
High Temperature ◽  
Atmospheric Co2 ◽  
Electrically Conductive ◽  
Oxidation Resistant ◽  
Coated Carbon
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