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聚合物转化SiHfCN陶瓷的制备及其吸波性能OA北大核心CSTPCD

Preparation and Wave-absorbing Properties of Polymer-derived SiHfCN Ceramics

中文摘要英文摘要

聚合物转化SiCN陶瓷得益于质量轻和热膨胀系数低等优势,在电磁波吸收领域受到广泛关注.由于电磁损耗机制单一及耐温性不足,SiCN陶瓷的吸波性能有待进一步提高,借助多组元协同作用增强吸波性能是可行的途径之一.本工作对聚氮硅烷结合不同化合物进行单源化改性得到SiHfCN、SiHfCN-C、SiHfCN-B和SiHfCN-N等四种纳米陶瓷.结果表明:SiHfCN中由于Hf源的含氧量高达13.5%(质量分数),生成HfO2和SiO2,使其最低反射损耗(Reflection loss,RLmin)仅为-13.8 dB,有效吸收带宽(Effective absorption bandwidth,EAB)仅为 0.42 GHz.相比于SiHfCN,含Hf聚合物分别与C源、B源和N源共改性增加了聚合物转化陶瓷的界面和导电相,SiHfCN-C、SiHfCN-B和SiHfCN-N的介电常数实部和虚部分别提高了 1.4~1.8和2.7~3.9倍,RLmin分别为-50.6、57.3和-63.5 dB,EAB分别为3.53、3.99和4.01 GHz,吸波性能得到了显著改善.SiHfCN-C中大量的自由碳抑制了 HfO2的生成,增强了电导损耗.SiHfCN-B中生成了 B-N和B-C键,且析出的纳米棒状HfSiO4提供了更多的异质界面,增强了极化损耗.SiHfCN-N中因引入大量N使N-C键数量增加,强化了偶极子极化损耗,同时生成纳米碳片,不仅可以增强电导损耗,而且提供大量界面,改善了阻抗匹配并增强了界面极化,因而SiHfCN-N具有最佳的吸波性能.

Polymer-derived SiCN ceramics benefiting from advantages of light mass and low coefficient of thermal expansion,have received wide attention in electromagnetic wave absorption field.However,the wave absorptive performance of SiCN ceramics needs to be further improved due to its monomer loss mechanism and insufficient temperature resistance.Enhancing their wave absorptive performance with the aid of multicomponent synergy is a feasible way,but still facing some challenges in preparation and wave absorption.In this work,four types of nanoceramics,SiHfCN,SiHfCN-C,SiHfCN-B,and SiHfCN-N were obtained by single-source modification of polysilazane combining different compounds.The results showed that SiHfCN generated HfO2 and SiO2 for up to 13.5%(in mass)oxygen content in the Hf source,resulting in the minimum reflection loss(RLmin)of only-13.8 dB and the effective absorption bandwidth(EAB)of only 0.42 GHz.Compared to SiHfCN,the co-modification of the Hf-containing polymer with C,B and N sources increased the interface and conductive phases of polymer-derived ceramics,real and imaginary parts of SiHfCN-C,SiHfCN-B,and SiHfCN-N gave rise to 1.4-1.8 and 2.7-3.9 times higher,respectively,with RLmin of-50.6,-57.3 and-63.5 dB,and EAB of 3.53,3.99 and 4.01 GHz,showing a significant improvement in their wave absorptive properties.The SiHfCN-C inhibited the generation of HfO2 for massive free carbon,which could enhance the conductivity loss.The SiHfCN-B generated B-N and B-C bonds,and precipitated nanorods of HfSiO4 to provide more heterogeneous interfaces,increasing the polarization loss.The SiHfCN-N increased the content of N-C bond due to the introduction of abundant N,enhancing the dipole polarization loss,while the generated carbon nanosheets not only enhanced the conductivity loss but also provided rich interfaces,which improved the impedance matching and amplified the polarization loss,thus exhibiting excellent wave absorptive performance.

张育育;吴轶城;孙佳;付前刚

西北工业大学超高温结构复合材料重点实验室,陕西省纤维增强轻质复合材料重点实验室,西安 710072

聚合物转化陶瓷聚氮硅烷超高温陶瓷吸波性能

polymer-derived ceramicpolysilazaneultra-high temperature ceramicwave-absorbing property

《无机材料学报》 2024 (006)

681-690 / 10

国家重点研发计划(2022YFB3708600,2021YFA0715802);国家自然科学基金(52101098);航空科学基金(2022Z055053004)National Key R&D Program of China(2022YFB3708600,2021YFA0715802);National Natural Science Foundation of China(52101098);Aeronautical Science Foundation of China(2022Z055053004)

10.15541/jim20230546

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