High-Temperature Oxidation-Resistant ZrN0.4B0.6/SiC Nanohybrid for Enhanced Microwave Absorption
High-Temperature Oxidation-Resistant ZrN0.4B0.6/SiC Nanohybrid for Enhanced Microwave Absorption
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DOI：
10.1021/acsami.8b22448
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发表时间：
2019-05-01
影响因子：
9.5
通讯作者：
Mahmood, Nasir
中科院分区：
文献类型：
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作者：
Jian, Xian;Tian, Wei;Mahmood, Nasir
大多数微波吸收剂在苛刻的工作条件下失去功能，例如高温和氧化环境。在这里，我们开发了一个异质ZrN0.4B0.6/SiC纳米杂化材料，通过结合催化化学气相沉积（CCVD）和化学气相渗透（CVI）工艺使用ZrB 2作为起始材料。通过调整CCVD和CVI工艺参数，如反应温度、反应时间和反应物浓度来控制ZrN0.4B0.6/SiC纳米杂化材料的组成和结构。最佳的非均相ZrN0.4B0.6/SiC纳米杂化材料最初通过在650 ℃下通过CCVD工艺制备ZrB2@C 30 min，随后在1500 ℃下通过CVI制备，其中ZrB2@C在N2下与Si反应。ZrN0.4B0.6/SiC纳米杂化材料表现出增强的微波吸收能力，在7.7 GHz下的最小反射损耗值约为-50.8 dB，厚度约为3.05 mm，并且在600 ℃的高温下具有抗氧化特性。异质ZrN0.4B0.6/SiC纳米杂化材料具有合理的导电性，导致介电损耗，而SiC纳米纤维形成了一个三维网络，带来了更高的偶极矩，而一小部分的ZrN0.4B0.6/SiC纳米杂化结构产生了一个有效的界面，更高的微波衰减。因此，这些材料特征协同地导致了良好定义的德拜弛豫、麦克斯韦-瓦格纳弛豫、偶极极化和四分之一波长抵消，这解释了增强的微波吸收。
Most microwave absorbers lose their function under harsh working conditions, such as a high temperature and an oxidative environment. Here, we developed a heterogeneous ZrN0.4B0.6/SiC nanohybrid via combined catalytic chemical vapor deposition (CCVD) and chemical vapor infiltration (CVI) processes using ZrB2 as the starting material. The composition and structure of the ZrN0.4B0.6/SiC nanohybrid were controlled by tuning the CCVD and CVI parameters, such as reaction temperature, time, and reactant concentration. The optimal heterogeneous ZrN0.4B0.6/SiC nanohybrids were obtained initially by preparing ZrB2@C via the CCVD process at 650 degrees C for 30 min and the subsequent CVI at 1500 degrees C, where the ZrB2@C reacted with Si under N-2. The ZrN0.4B0.6/SiC nanohybrid exhibited enhanced microwave absorption ability with a minimum reflection loss value of approximately -50.8 dB at 7.7 GHz, a thickness of similar to 3.05 mm, and antioxidation features at a high temperature of 600 degrees C. The heterogeneous ZrN0.4B0.6/SiC nanohybrid possessed reasonable conductivity, leading to dielectric loss, whereas SiC nanofibers formed a three-dimensional network that brought higher dipole moments, whereas a small part of the ZrN0.4B0.6/SiC nanohybrid structure generated an effective interface for higher attenuation of microwaves. Therefore, these material features synergistically resulted in a well-defined Debye relaxation, Maxwell-Wagner relaxation, dipole polarization, and the quarter-wavelength cancellation, which accounted for the enhanced microwave absorption.