Enhanced high-temperature dielectric properties and microwave absorption of SiC nanofibers modified Si3N4 ceramics within the gigahertz range

Zhou, Wei; Yin, Rui; Long, Lan; Luo, Hang; Hu, Weida; Ding, Yanhong; Yang, Li

doi:10.1016/j.ceramint.2018.04.017

“…Consequently, high‐performance EM wave absorbing materials which have drawn increasing attention are now regarded as an effective strategy to eliminate the EM pollution. Carbon‐based composites, 5‐9 metal‐based composites, 10‐14 polymer‐based composites, 15‐19 and ceramic‐based composites, 20‐24 have been extensively studied for EM wave absorption application. However, applications of carbon, metal, and polymer‐based composites are limited at elevated temperatures due to their degraded strength and EM wave absorption under oxidizing and/or corrosive atmosphere 25 .…”

Section: Introductionmentioning

confidence: 99%

Dielectric response and electromagnetic wave absorption of novel macroporous short carbon fibers/mullite composites

Long

¹

,

Xu

²

,

Luo

³

et al. 2020

Self Cite

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Nowadays, electromagnetic (EM) interference and radiation pollution generated from widespread application of electronic devices, could damage the normal function of electronic equipment as well as humanity. 1-4 Consequently, high-performance EM wave absorbing materials which have drawn increasing attention are now regarded as an effective strategy to eliminate the EM pollution. Carbon-based composites, 5-9 metal-based composites, 10-14 polymer-based composites, 15-19 and ceramic-based composites, 20-24 have been extensively studied for EM wave absorption application. However, applications of carbon, metal, and polymer-based composites are limited at elevated temperatures due to their degraded strength and EM wave absorption under oxidizing and/or corrosive atmosphere. 25 Therefore, ceramic-based composites with lightweight, excellent high-temperature strength, and outstanding thermal-chemical stability, are regarded as the most promising candidates of EM wave absorbing materials for high-temperature applications.

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“…Excellent absorption materials should have, apart from a great loss ability for electromagnetic waves, a good impedance matching characteristic to reduce the reflection of electromagnetic waves on the surface of the material [65]. The ability of reflecting electromagnetic waves and the impedance matching characteristic of a material can be expressed by reflection coefficient Γ [71]:…”

Section: Microwave Absorption Propertiesmentioning

confidence: 99%

High-thermally conductive AlN-based microwave attenuating composite ceramics with spherical graphite as attenuating agent

Xia

¹

,

Jiang

²

,

Pan

³

et al. 2020

Preprint

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High-thermally conductive AlN-based microwave attenuating composite ceramics with spherical graphite (SG) as the attenuating agent were fabricated through hot-pressing sintering. The SG maintains its three-dimensional morphology within the sintered bodies, which considerably impedes the sintering of the composites to some extent but slightly influences on the growth of AlN grains. The addition of SG reduces the strength of the composites, but provides a moderate toughening effect at the optimal addition amount (3.8 MPa·m1/2 at 4 wt% SG). Benefiting from the low anisotropy, high thermal conductivity, and the three-dimensional morphology of SG, the composites exhibit a relatively higher thermal conductivity (76.82 W·m-1·k-1 at 10 wt% SG) compared with composites added with non-spherical attenuating agent. The dielectric constant and loss (8.2–12.4 GHz) increase remarkably as the amount of SG added increases up to 8 wt%, revealing that the incorporation of SG improves the dielectric property of the composite. The composite with 7 wt% SG exhibits the best absorption performance with a minimum reflection loss of -14 dB at 12.4 GHz and an effective absorbing bandwidth of 0.87 GHz. The excellent overall properties of the SG/AlN microwave attenuating composites render them as a promising material for various applications. Moreover, SG has a great potential as an attenuating agent for microwave attenuating composites due to its strong attenuation upon integration, high thermal conductivity, and low anisotropy.

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“…Excellent absorption materials should have, apart from a great loss ability for electromagnetic waves, a good impedance matching characteristic to reduce the reflection of electromagnetic waves on the surface of the material [62]. The ability of a material to reflect electromagnetic waves and the impedance matching characteristic of a material can be expressed by reflection coefficient Γ [65]:…”

Section: Microwave Absorption Propertiesmentioning

confidence: 99%

High-thermally Conductive AlN-based Microwave Attenuating Composite Ceramics with Spherical Graphite as Attenuating Agent

Xia

¹

,

Jiang

²

,

Pan

³

et al. 2020

Preprint

0

View full text Add to dashboard Cite

High-thermally conductive AlN-based microwave attenuating composite ceramics with spherical graphite (SG) as the attenuating agent were fabricated through hot-pressing sintering. The SG maintains its three-dimensional morphology within the sintered bodies, which considerably impedes the sintering of the composites to some extent but slightly influences on the growth of AlN grains. The addition of SG reduces the strength of the composites, but provides a moderate toughening effect at the optimal addition amount (3.8 MPa·m1/2 at 4 wt% SG). Benefiting from the low anisotropy, high thermal conductivity, and the three-dimensional morphology of SG, the composites exhibit a relatively higher thermal conductivity (76.82 W·m-1·k-1 at 10 wt% SG) compared with composites added with non-spherical attenuating agent. The dielectric constant and loss (8.2–12.4 GHz) increase remarkably as the amount of SG added increases up to 8 wt%, revealing that the incorporation of SG improves the dielectric property of the composite. The composite with 7 wt% SG exhibits the best absorption performance with a minimum reflection loss of -14 dB at 12.4 GHz and an effective absorbing bandwidth of 0.87 GHz. The excellent overall properties of the SG/AlN microwave attenuating composites render them as a promising material for various applications. Moreover, SG has a great potential as an attenuating agent for microwave attenuating composites due to its strong attenuation upon integration, high thermal conductivity, and low anisotropy.

show abstract

Enhanced high-temperature dielectric properties and microwave absorption of SiC nanofibers modified Si3N4 ceramics within the gigahertz range

Cited by 98 publications

References 52 publications

Dielectric response and electromagnetic wave absorption of novel macroporous short carbon fibers/mullite composites

Dielectric response and electromagnetic wave absorption of novel macroporous short carbon fibers/mullite composites

High-thermally conductive AlN-based microwave attenuating composite ceramics with spherical graphite as attenuating agent

High-thermally Conductive AlN-based Microwave Attenuating Composite Ceramics with Spherical Graphite as Attenuating Agent

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