Science and Technology on Thermostructural Composite Materials Laboratory , Northwestern Polytechnical University , 710072 Xi'an , China.
Temasek Laboratories , National University of Singapore , 5A Engineering Drive 1 , 117411 , Singapore.
ACS Appl Mater Interfaces. 2018 Sep 5;10(35):29876-29883. doi: 10.1021/acsami.8b07980. Epub 2018 Aug 7.
Hafnium carbide (HfC) phase, with a high melting point, excellent strength, and high electrical conductivity, could be a suitable addition to enhance the microwave absorption properties of one-dimensional silicon carbide (SiC) nanomaterials without sacrificing its high-temperature thermal stability. In the present work, HfC/SiC hybrid nanofiber mats with different HfC loading contents are fabricated by electrospinning and high-temperature pyrolysis. HfC hybrids with sizes of 5-10 nm are embedded in the SiC nanofibers. As the HfC content increases from 0 to 6.3 wt %, the average diameter of the fibers drops from 2.62 μm to 260 nm. Meanwhile, the electrical conductivity rises from 7.9 × 10 to 4.2 × 10 S/cm. Moreover, the flexibility of the nanofiber mats is also greatly improved, according to a 200-times 180° bending test. Furthermore, compared with pure SiC fiber mats, the HfC/SiC nanofiber mats possess much larger dielectric loss because of higher electrical conductivity. At the optimal HfC content of 2.5 wt %, the HfC/SiC nanofibers/silicon resin composite (10 wt %) exhibits a minimal reflection loss (RL) of -33.9 dB at 12.8 GHz and a 3 mm thickness with a broad effective absorption bandwidth (RL < -10 dB) of 7.4 GHz. The above results prove that introducing HfC into SiC nanofiber mats is an effective way to enhance their flexibility, dielectric properties, and microwave absorption performance.
碳化铪（HfC）相具有高熔点、优异的强度和高导电性，可作为一种合适的添加剂，在不牺牲其高温热稳定性的情况下，增强一维碳化硅（SiC）纳米材料的微波吸收性能。在本工作中，通过静电纺丝和高温热解制备了不同 HfC 负载量的 HfC/SiC 杂化纳米纤维毡。尺寸为 5-10nm 的 HfC 杂化物嵌入 SiC 纳米纤维中。随着 HfC 含量从 0 增加到 6.3wt%，纤维的平均直径从 2.62μm 降至 260nm。同时，电导率从 7.9×10-4S/cm 上升到 4.2×10-4S/cm。此外，根据 200 次 180°弯曲测试，纳米纤维毡的柔韧性也得到了极大的提高。此外，与纯 SiC 纤维毡相比，由于较高的电导率，HfC/SiC 纳米纤维毡具有更大的介电损耗。在最佳的 HfC 含量为 2.5wt%时，HfC/SiC 纳米纤维/硅树脂复合材料（10wt%）在 12.8GHz 下表现出最小反射损耗（RL）为-33.9dB，厚度为 3mm 时有效吸收带宽（RL<-10dB）为 7.4GHz。上述结果证明，将 HfC 引入 SiC 纳米纤维毡是增强其柔韧性、介电性能和微波吸收性能的有效方法。
