High-thermally conductive AlN-based microwave attenuating composite ceramics with spherical graphite as attenuating agent
| Autor: | Tai Qiu, Xia Fang, Lei Jiang, Limei Pan, Jian Yang, Shuang Yin |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Materials science
microwave absorption Reflection loss Composite number Sintering Dielectric Electronic Optical and Magnetic Materials lcsh:TP785-869 Thermal conductivity lcsh:Clay industries. Ceramics. Glass visual_art Ceramics and Composites visual_art.visual_art_medium dielectric property thermal conductivity Graphite Ceramic aluminum nitride Composite material spherical graphite (SG) Microwave |
| Zdroj: | Journal of Advanced Ceramics, Vol 10, Iss 2, Pp 301-319 (2021) |
| ISSN: | 2227-8508 2226-4108 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full text from SpringerLink