scholarly journals Porous SiC Ceramic Matrix CompositeReinforced by SiC Nanowires with High Strength and Low Thermal Conductivity

2021 ◽  
pp. 230
Author(s):  
RUAN Jing ◽  
YANG Jinshan ◽  
YAN Jingyi ◽  
YOU Xiao ◽  
WANG Mengmeng ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
High Strength ◽  
Ceramic Matrix ◽  
Low Thermal Conductivity ◽  
Sic Nanowires ◽  
Sic Ceramic ◽  
Porous Sic

scholarly journals Porous Design of SiCNWs/SiC Nanocomposites with High Strength and Low Thermal Conductivity

2021 ◽  
Author(s):  
Jing Ruan ◽  
Jinshan Yang ◽  
Jingyi Yan ◽  
Xiao You ◽  
Mengmeng Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Volume Fraction ◽  
Chemical Deposition ◽  
High Strength ◽  
Chemical Vapor Infiltration ◽  
Spherical Particles ◽  
Uniform Structure ◽  
Low Thermal Conductivity ◽  
Sic Composites ◽  
Porous Sic

Abstract Porous SiC composites with lightweight, high strength and low thermal conductivity design can be obtained by constructing porous silicon carbide nanowires (SiCNWs) network and controlling chemical vapor infiltration (CVI) process. The SiCNWs network with an optimized volume fraction (13.6%) and uniform structure is prepared by mixing SiCNWs and polyvinyl alcohol (PVA) firstly. SiCNWs reinforced porous SiC composite (SiCNWs/SiC) with a small uniform pore can be obtained by controlling the chemical deposition kinetics. The morphology of the grown SiC matrix, from the spherical particles to the hexagonal pyramid particles, can be influenced by the deposition parameters like temperature and reactive gas concentration. The strength of the lightweight SiCNWs/SiC composites reach 47.8 MPa with a porosity of 64% and thermal conductivity of 1.2 W/(m∙K), which shows the toughening effect and insulation design with low thermal conductivity.

scholarly journals Porous Design of SiCNWs/SiC Nanocomposites with High Strength and Low Thermal Conductivity

2021 ◽  
Author(s):  
Jing Ruan ◽  
Jinshan Yang ◽  
Jingyi Yan ◽  
Xiao You ◽  
Mengmeng Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Volume Fraction ◽  
Chemical Deposition ◽  
High Strength ◽  
Chemical Vapor Infiltration ◽  
Spherical Particles ◽  
Uniform Structure ◽  
Low Thermal Conductivity ◽  
Sic Composites ◽  
Porous Sic

Abstract Porous SiC composites with lightweight, high strength and low thermal conductivity design can be obtained by constructing porous silicon carbide nanowires (SiCNWs) network and controlling chemical vapor infiltration (CVI) process. The SiCNWs network with an optimized volume fraction (13.6%) and uniform structure is prepared by mixing SiCNWs and polyvinyl alcohol (PVA) firstly. SiCNWs reinforced porous SiC composite (SiCNWs/SiC) with a small uniform pore can be obtained by controlling the chemical deposition kinetics. The morphology of the grown SiC matrix, from the spherical particles to the hexagonal pyramid particles, can be influenced by the deposition parameters like temperature and reactive gas concentration. The strength of the lightweight SiCNWs/SiC composites reach 47.8 MPa with a porosity of 64% and thermal conductivity of 1.2 W/(m∙K), which shows the toughening effect and insulation design with low thermal conductivity.

scholarly journals Fabrication of Natural Flake Graphite/Ceramic Composite Parts with Low Thermal Conductivity and High Strength by Selective Laser Sintering

2020 ◽  
Vol 10 (4) ◽  
pp. 1314
Author(s):  
Haihua Wu ◽  
Kui Chen ◽  
Yafeng Li ◽  
Chaoqun Ren ◽  
Yu Sun ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Compressive Strength ◽  
Ceramic Composite ◽  
Selective Laser Sintering ◽  
High Strength ◽  
Laser Sintering ◽  
Post Processing ◽  
Composite Part ◽  
Low Thermal Conductivity ◽  
Powder Composition

The 3D graphite/ceramic composite prototyping parts directly prepared by selective laser sintering (SLS) were porous, which led to poor strength and low thermal conductivity. In order to obtain low thermal conductivity and high strength, its thermal conductivity and compressive strength were adjusted by changing the mixture powder composition and adding post-processing. The result showed that the addition of silicon powder in the mixture powder could significantly improve the compressive strength and thermal conductivity. The addition of expanded graphite was beneficial to the formation of the closed pores in the matrix, which slightly reduced the compressive strength but significantly reduced the thermal conductivity. The 3D graphite/ceramic composite part showed an order of magnitude improvement in compressive strength (from 1.25 to 13.87 MPa) but relatively small change in thermal conductivity (from 1.40 to 2.12 W·m−1K−1) and density (from 0.53 to 1.13 g·cm−3) by post-processing. Reasonable mixture powder composition and post-processing were determined and realized the possibility of fabricating a 3D graphite/ceramic composite part with low thermal conductivity but high compressive strength. Furthermore, it could be used for the repeated casting of steel castings, and through the comparative analysis of casting defects, the prepared graphite/ceramic composite part was expected to replace water glass sand mold.

Elephant ivory: A low thermal conductivity, high strength nanocomposite

2006 ◽  
Vol 21 (1) ◽  
pp. 287-292 ◽  
Author(s):  
Michael B. Jakubinek ◽  
Champika J. Samarasekera ◽  
Mary Anne White
Keyword(s):  
Thermal Conductivity ◽  
Room Temperature ◽  
High Strength ◽  
Mean Free Path ◽  
Boundary Scattering ◽  
Low Thermal Conductivity ◽  
Recent Interest ◽  
Elephant Ivory ◽  
Nanocomposite Structures ◽  
Structure Properties

There has been much recent interest in heat transport in nanostructures, and alsoin the structure, properties, and growth of biological materials. Here we present measurements of thermal properties of a nanostructured biomineral, ivory. The room-temperature thermal conductivity of ivory is anomalously low in comparison with its constituent components. Low-temperature (2–300 K) measurements ofthermal conductivity and heat capacity reveal a glass-like temperature dependenceof the thermal conductivity and phonon mean free path, consistent with increased phonon-boundary scattering associated with nanostructure. These results suggest that biomineral-like nanocomposite structures could be useful in the design of novel high-strength materials for low thermal conductivity applications.

Low-Temperature Sintering of Porous Silicon Carbide Ceramics with H3PO4 as an Additive

2018 ◽  
Vol 281 ◽  
pp. 311-315 ◽  
Author(s):  
Tian Gu ◽  
Fei Chen ◽  
Hai Long Yuan ◽  
Qiang Shen ◽  
Lian Meng Zhang
Keyword(s):  
Phosphoric Acid ◽  
Bending Strength ◽  
Sintering Temperature ◽  
High Strength ◽  
High Porosity ◽  
Low Temperature Sintering ◽  
Sic Ceramic ◽  
Carbide Ceramics ◽  
Porous Sic ◽  
Silicon Carbide Ceramics

In this paper, the raw SiC powder is oxidized at high temperature (1000 °C for 4h), and a layer of SiO2oxide film is formed on the surface of SiC particles. By adding phosphoric acid, phosphoric acid reacts with SiO2at lower temperatures to form phosphate. Phosphate decomposition produces gas to create pores. At 1200 °C, the phosphate is completely decomposed into SiO2, and a large amount of gas is produced to prepare porous SiC ceramic with high porosity and high strength. The effects of H3PO4content on the phase composition, microstructure, porosity and mechanical properties of the prepared porous SiC ceramic were investigated. With the increase of H3PO4content, the porosity increased and the bending strength decreased. The results suggest that at the sintering temperature of 1200 °C, the porosity of the samples can reach 58.3%~71.2%, while the bending strength of them can reach 8.72~31.09 MPa.

Ultra-low thermal conductivity and high strength of aerogels/fibrous ceramic composites

2016 ◽  
Vol 36 (6) ◽  
pp. 1487-1493 ◽  
Author(s):  
Jian He ◽  
Xiaolei Li ◽  
Dong Su ◽  
Huiming Ji ◽  
XiaoJing Wang
Keyword(s):  
Thermal Conductivity ◽  
High Strength ◽  
Ceramic Composites ◽  
Low Thermal Conductivity
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