钴酸镍/亲水碳布微波吸收复合材料及其热裂解特性研究

Research on Nickel Cobalt Oxide / Hydrophilic Carbon Cloth Microwave Absorption Composites and Their Thermal Cracking Characteristics

摘要:

随着智能电子设备的普及，电磁辐射污染问题愈发严峻，开发新型高性能微波吸收材料已成为当下新材料领域的一大研究热点。由于微波吸收材料的吸波性能在高温条件下会出现不同程度的衰减，因此，针对高温环境下微波吸收材料的吸波性能变化及热裂解特性展开研究。采用简易水热法与高温煅烧相结合的工艺，将钴酸镍（Nickel cobalt oxide，NiCo₂O₄）成功负载于亲水碳布（Hydrophilic carbon cloth，HCC），获得具有优异热稳定性和微波吸收性能的NiCo₂O₄/HCC复合材料。通过SEM、XRD和XPS对NiCo₂O₄/HCC复合材料进行了微观结构与材料成分分析，通过VNA和TGA-IR对NiCo₂O₄/HCC复合材料进行了吸波性能和热裂解特性测试。结果表明，针状NiCo₂O₄均匀地负载于HCC表面，这为NiCo₂O₄/HCC复合材料引入了磁损耗。与纯HCC基体相比，针状NiCo₂O₄与HCC形成的异质界面结构使NiCo₂O₄/HCC复合材料的微波吸收能力得到显著提升。XRD和XPS分析结果表明，NiCo₂O₄/HCC复合材料中的NiCo₂O₄为尖晶石结构。当填充的NiCo₂O₄质量分数为25%及厚度为4.98 mm时，NiCo₂O₄/HCC复合材料的反射损耗（RL）高达-50.00 dB。TGA-IR分析结果表明，NiCo₂O₄/HCC复合材料在25—800 ℃范围的质量损失率主要源于HCC上功能基团和NiCo₂O₄的分解。经25—800 ℃的高温热裂解后，NiCo₂O₄/HCC复合材料的RL为-48.67 dB，较热裂解前的RL强度损失率小于5%，表明该复合材料在高温环境下依然保持着良好的微波吸收性能。制备的NiCo₂O₄/HCC复合材料有望成为高温微波吸收材料的潜在选择之一，为指导该材料在高温场景中的实际应用提供一定的理论支撑。（专精特新·电磁波吸收与屏蔽用新型材料的研究进展专辑十二之八）

Abstract:

With the increasing popularity of smart electronic devices， the problem of electromagnetic radiation pollution caused by them is becoming increasingly severe. Developing new high-performance microwave absorbing materials has become one of the research hotspots in the field of new materials. One of the critical issues in the application of microwave absorbing materials is that their absorption performance often decreases to varying degrees at high-temperature. Therefore， research on the changes in microwave absorbing performance and thermal cracking characteristics of microwave absorbing materials under high-temperature environment can provide a theoretical basis for guiding their practical applications in high-temperature environment. In this paper， nickel cobalt oxide （NiCo₂O₄） was successfully loaded onto hydrophilic carbon cloth （HCC） by combining a facile hydrothermal method with high-temperature calcination， which fully utilizing the advantages of both components to obtain NiCo₂O₄/HCC composites with excellent thermal stability and microwave absorption properties. The SEM， XRD， and XPS were used to analyze the microstructure and material composition of NiCo₂O₄/HCC composites. The VNA and TGA-IR were used to test the microwave absorbing performance and thermal cracking characteristics of NiCo₂O₄/HCC composites. The results indicate that needle-shaped NiCo₂O₄ is uniformly loaded onto HCC， which can introduce magnetic losses into NiCo₂O₄/HCC composites； Compared with single HCC material， needle-shaped NiCo₂O₄ and its heterogeneous interface structure significantly enhance the microwave absorbing performance of NiCo₂O₄/HCC composites. The XRD and XPS analysis results indicate that NiCo₂O₄ in the NiCo₂O₄/HCC composites has a spinel structure. When the filling ratio is 25 wt% and the thickness is 4.98 mm， the reflection loss （RL） of NiCo₂O₄/HCC composites is as high as -50.00 dB. The TGA-IR analysis results of NiCo₂O₄/HCC composites in the range of 25—800 ℃ indicate that the mass loss rate may be mainly attributed to the decomposition of functional groups on HCC and NiCo₂O₄. After high-temperature thermal cracking at 25—800 ℃， the RL of NiCo₂O₄/HCC composites is -48.67 dB， with a strength loss rate of less than 5% compared to before high-temperature thermal cracking， indicating that the composites still maintain good microwave absorbing performance in high-temperature environment. Therefore， the prepared NiCo₂O₄/HCC composites is expected to become one of the potential choices for high-temperature microwave absorbing materials.