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硅酸盐通报 ›› 2022, Vol. 41 ›› Issue (12): 4432-4443.

所属专题: 陶瓷

• 陶瓷 • 上一篇    下一篇

高熵(Zr,Hf,Nb,Ta)C微米长方体的制备、吸波性能和抗氧化性研究

李俐1,2, 于宏林3, 徐文喆2, 耿欣2   

  1. 1.山东硅纳新材料科技有限公司,淄博 255400;
    2.山东理工大学工程陶瓷研究院,淄博 255030;
    3.山东工业陶瓷研究设计院有限公司,淄博 255035
  • 收稿日期:2022-07-26 修订日期:2022-09-05 出版日期:2022-12-15 发布日期:2023-01-11
  • 通信作者: 于宏林,高级工程师。E-mail:88790264@qq.com
  • 作者简介:李 俐(1983—),女,高级工程师。主要从事无机功能材料和特种陶瓷材料的研究。E-mail:dazlious@163.com

Preparation, Microwave Absorption Properties and Oxidation Resistance of High-Entropy (Zr,Hf,Nb,Ta)C Microcuboids

LI Li1,2, YU Honglin3, XU Wenzhe2, GENG Xin2   

  1. 1. Shandong Si-Nano Materials Technology Co., Ltd., Zibo 255400, China;
    2. Institute of Engineering Ceramics, Shandong University of Technology, Zibo 255030, China;
    3. Shandong Industrial Ceramics Research & Design Institute Co., Ltd., Zibo 255035, China
  • Received:2022-07-26 Revised:2022-09-05 Online:2022-12-15 Published:2023-01-11

摘要: 针对高熵碳化物制备困难,本文采用ZrC、HfC、NbC和TaC粉为原料,Ni粉为熔剂,通过低温无压烧结工艺成功制备出三种不同成分的高熵(Zr,Hf,Nb,Ta)C粉体。结果表明,三种粉体均为微米长方体,且暴露(100)晶面。(Zr1/4Hf1/4Nb1/4Ta1/4)C微米长方体因具有高介电常数而展现出优异的吸波性能,在厚度为3.5 mm、频率为6.16 GHz时,最低反射损耗值可达-48.86 dB。高熵(Zr,Hf,Nb,Ta)C微米长方体在800~1 200 ℃下展示出优异的抗氧化性,且氧化产物均由正交相(NbxTa1-x)2O5固溶体、单斜相(ZrxHf1-x)O2固溶体和正交相HfO2所组成,与氧化温度和过渡金属的物质的量比无关。Zr、Hf、Nb和Ta的协同作用导致其氧化机制与单组元碳化物截然不同,Hf的存在抑制Nb2O5由正交晶系向单斜晶系转变,还会促使ZrO2在800 ℃时由四方晶系转变为单斜晶系。此外,Nb和Ta的存在促使HfO2在常压下由单斜晶系转变为四方晶系。

关键词: 高熵碳化物陶瓷, (Zr,Hf,Nb,Ta)C, 微米长方体, 吸波性能, 抗氧化性

Abstract: In response to the difficulty of the synthesis of high-entropy carbides (HECs), a pressureless low-temperature sintering strategy was utilized to prepare (Zr,Hf,Nb,Ta)C powders with three different transition metal proportion, which powder mixtures of ZrC, HfC, NbC, TaC and Ni were initially annealed at 1 500 ℃ under a flowing Ar atmosphere, and then etched by the nitric acid solution in order to dissolve the metal matrix. The results show that all samples exhibit cuboid morphology with an average size of 2 μm and the exposure of (100) face. Due to high dielectric constant, (Zr1/4Hf1/4Nb1/4Ta1/4)C microcuboids show good microwave absorption performance, and its minimum value of reflection loss attains -48.86 dB at a thickness of 3.5 mm and a frequency of 6.16 GHz. As-fabricated HECs samples also possess good oxidation resistance at 800~1 200 ℃. Moreover, oxidation products are irrelevant to the transition metal proportion and oxidation temperature, which are composed of orthorhombic Nb2O5-Ta2O5 solid solution (o-(NbxTa1-x)2O5), monoclinic ZrO2-HfO2 solid solution (m-(ZrxHf1-x)O2) and orthorhombic HfO2(o-HfO2). Notably, the synergy effect caused by transition metal elements significantly influences the phase transition process of oxides in comparison with monocarbide. In specific, the existence of Hf inhibits the transition of Nb2O5 from orthorhombic to monoclinic, in the meantime, assists the transition of ZrO2 from tetragonal to monoclinic even at 800 ℃. Moreover, the addition of Nb and Ta accelerates the phase transition of HfO2 from monoclinic to orthorhombic under atmospheric pressure.

Key words: high-entropy carbides ceramics, (Zr,Hf,Nb,Ta)C, microcuboid, microwave absorption property, oxidation resistance

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