Xu Weimin, Li Shibo, Zhang Weiwei, Ouyang Bo, Yu Wenbo, Zhou Yang
Center of Materials Science and Engineering, School of Mechanical and Electronic Control Engineering, Beijing Jiaotong University, Beijing 100044, China.
Research Center of Rail Vehicles Safety Monitoring and Health Management, Beijing Jiaotong University, Beijing 100044, China.
ACS Appl Mater Interfaces. 2021 Oct 20;13(41):49242-49253. doi: 10.1021/acsami.1c17015. Epub 2021 Oct 8.
TiCT has microwave absorption (MA) properties due to its dielectric loss, but the absence of magnetic loss capability of pure TiCT causes unmatched impedance and unsatisfied MA performance. Modification of TiCT with magnetic particles is an effective way to introduce the magnetic loss mechanism. However, these modified TiCT particles have higher density and require complicated fabrication processes, restricting the industrial production and functional applications. Here, a low-temperature and simple method of radio-frequency N plasma treatment was adopted to modify TiCT with N. More interestingly, the N-doped TiCT flakes demonstrated magnetic properties and thus exhibited drastically enhanced MA properties. The minimum reflection loss (RL) of -59.20 dB at 10.56 GHz was achieved in N-doped TiCT products after only 3 min of plasma treatment, remarkably higher than RL of -11.07 dB at 7.92 GHz for the pristine TiCT. The main mechanism is due to the combination of dielectric loss, magnetic loss, and the good impedance matching in the N-doped TiCT. Further prolonging the nitriding time induces much desorption of -F and the formation of TiO, thus deteriorating the impedance matching and the MA properties.
TiCT因其介电损耗而具有微波吸收（MA）特性，但纯TiCT缺乏磁损耗能力，导致阻抗不匹配且MA性能不理想。用磁性颗粒对TiCT进行改性是引入磁损耗机制的有效方法。然而，这些改性TiCT颗粒密度较高，且制备工艺复杂，限制了其工业化生产和功能应用。在此，采用低温且简单的射频N等离子体处理方法对TiCT进行N改性。更有趣的是，N掺杂的TiCT薄片表现出磁性，因此MA性能大幅增强。仅经过3分钟的等离子体处理，N掺杂TiCT产品在10.56 GHz处实现了-59.20 dB的最小反射损耗（RL），显著高于原始TiCT在7.92 GHz处-11.07 dB的RL。主要机制是由于N掺杂TiCT中的介电损耗、磁损耗以及良好的阻抗匹配。进一步延长氮化时间会导致大量-F脱附并形成TiO，从而使阻抗匹配和MA性能恶化。
