The proliferation of high-power,highly informationized,and highly integrated electronic devices and weapons equipment has given rise to increasingly conspicuous issues about electromagnetic(EM)pollution and thermal ac...The proliferation of high-power,highly informationized,and highly integrated electronic devices and weapons equipment has given rise to increasingly conspicuous issues about electromagnetic(EM)pollution and thermal accumulation.These issues,in turn,impose constraints on the performance of such equipment and jeopardize personnel safety.Carbon materials,owing to their diverse and modifiable structures,offer adjustable thermal and electric conductivity,rendering them highly promising for applications in fields such as thermal management and EM protection which have garnered extensive research and review.The pursuit of integrated device and equipment development has elevated the demand for multifunctional materials,prompting significant research into carbon-based composite materials that include both thermal management and EM protection functionalities.Notably,there are no relevant reviews on this topic at present.Consequently,this work consolidates research findings from recent years on carbon matrix composites exhibiting dual attributes of thermal management and EM protection.These attributes include thermally conductive electromagnetic interference(EMI)shielding materials,thermally insulating EMI shielding materials,thermally conductive EM wave(EMW)absorbing materials,and thermally insulating EMW absorbing materials.The paper elucidates the fundamental principles underpinning thermal conduction,thermal insulation,EMW absorbing,and EMI shielding.Additionally,it engages in discussions surrounding areas of contention,design strategies,and the functional properties of various material designs.Ultimately,the paper concludes by presenting the challenges encountered and potential research strategies about composites endowed with both thermal management and EM protection functionalities,while also envisaging the development of novel multifunctional EM protection materials.展开更多
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(...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(3D) 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·m^(1/2) at 4 wt% SG). Benefiting from the low anisotropy, high thermal conductivity, and the 3D 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 –13.9 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.展开更多
基金supported by the National Key R&D Program of China(No.2022YFB3805702)the National Natural Science Foundation of China(Nos.52173078,52130303,51973158,51803151,and 51973152)the Science Foundation for Distinguished Young Scholars in Tianjin(No.19JCJQJC61700).
文摘The proliferation of high-power,highly informationized,and highly integrated electronic devices and weapons equipment has given rise to increasingly conspicuous issues about electromagnetic(EM)pollution and thermal accumulation.These issues,in turn,impose constraints on the performance of such equipment and jeopardize personnel safety.Carbon materials,owing to their diverse and modifiable structures,offer adjustable thermal and electric conductivity,rendering them highly promising for applications in fields such as thermal management and EM protection which have garnered extensive research and review.The pursuit of integrated device and equipment development has elevated the demand for multifunctional materials,prompting significant research into carbon-based composite materials that include both thermal management and EM protection functionalities.Notably,there are no relevant reviews on this topic at present.Consequently,this work consolidates research findings from recent years on carbon matrix composites exhibiting dual attributes of thermal management and EM protection.These attributes include thermally conductive electromagnetic interference(EMI)shielding materials,thermally insulating EMI shielding materials,thermally conductive EM wave(EMW)absorbing materials,and thermally insulating EMW absorbing materials.The paper elucidates the fundamental principles underpinning thermal conduction,thermal insulation,EMW absorbing,and EMI shielding.Additionally,it engages in discussions surrounding areas of contention,design strategies,and the functional properties of various material designs.Ultimately,the paper concludes by presenting the challenges encountered and potential research strategies about composites endowed with both thermal management and EM protection functionalities,while also envisaging the development of novel multifunctional EM protection materials.
基金financially supported by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Postgraduate Research & Practice Innovation Program of Jiangsu Province (KYCX200990)+2 种基金Qing Lan Projectthe Program for Changjiang Scholars, Innovative Research Team in University (IRT1146 and IRT15R35)the Top-notch Academic Programs Project of Jiangsu Higher Education Institutions (TAPP, PPZY2015B128)。
文摘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(3D) 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·m^(1/2) at 4 wt% SG). Benefiting from the low anisotropy, high thermal conductivity, and the 3D 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 –13.9 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.
