硅酸盐学报2025，Vol.53Issue(3)：647-657,11.DOI:10.14062/j.issn.0454-5648.20240607
尖晶石/岩盐型(Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)CoxOy高熵陶瓷的制备与吸波性能
Preparation and Microwave Absorption Properties of Spinel/Rock Salt(Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)CoxOy High-Entropy Ceramics
摘要
Abstract
Introduction With the rapid development of wireless communication technology,electromagnetic waves are regarded as a main medium for energy and information transmission.Absorbing materials,as a focus of scientific research in recent years,play a key role in effectively reducing electromagnetic radiation pollution in the environment,thereby reducing the negative effect of electromagnetic waves.The design of absorbing materials follows the principles of"thin,light,wide,and strong"to meet practical applications.At present,there are various types of absorbing materials,mainly including magnetic metals,polymer based composite materials,ferrites,and carbon-based materials.However,all the materials have their limitations.For instance,magnetic materials have a superior performance,but they have a poor oxidation resistance,which are prone to eddy current losses,thus affecting the absorption efficiency.The preparation cost of polymer-based composite materials is high,and their application fields are limited.Ferrite materials have an insufficient temperature stability and a high surface density.In addition,carbon-based materials suffer from poor impedance matching and narrow absorption frequency bands.These inherent limitations hinder a widespread applicability of absorbing materials in diverse application scenarios.Therefore,developing novel absorbing materials with superior oxidation resistance and high-temperature stability has an important practical significance. Methods High-entropy multiphase oxide ceramics was prepared by a solid-state reaction method.In the preparation process,FeO,CoO,NiO,CuO,ZnO and Co2O3 as raw materials in a molar ratio of 1:1:1:1:1:5 were ground with anhydrous ethanol in a mill at 200 r/min for 8 h,and then dried at 80℃to obtain a mixed powder.Subsequently,8 g of the mixed powder was pressed into a round billet with a diameter of 30 mm at 10 MPa.The obtained round billet was then heated and reacted in a model BR-12N muffle furnace at different temperatures(i.e.,800,900,1000℃and 1100℃)for 6 h to obtain the samples of(Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)CoxOy high-entropy ceramics(HEO),which were named samples HEO-800,HEO-900,HEO-1000,and HEO-1100,respectively. Results and discussion The results show that the obtained samples HEO-800,HEO-900,HEO-1000,and HEO-1100 all exhibit spinel and rock salt phases,as well as pore structures and irregular blocks.The degree of crystallization gradually increases with increasing temperature,which can be attributed to the accelerated diffusion of atoms at the interface and the gradual increase in grain size due to the presence of oxygen vacancies.The XPS analysis indicates that the high-entropy multiphase oxide ceramics sintered at different temperatures all have oxygen vacancies,and the maximum oxygen vacancies occur at 900℃.The conductivity test shows that the sample HEO-900 has the maximum conductivity.The electromagnetic wave absorption test results reveal that the RLmin values of the samples HEO-800,HEO-900,HEO-1000,and HEO-1100 are-9.85,-36.14,-13.73 dB,and-4.61 dB,respectively.The sample HEO-900 obtained via sintering at 900℃has the optimum absorbing property.Except for the sample HEO-900,the reflection loss of other samples is not high mainly due to the weak dielectric loss caused by low oxygen vacancy,while the magnetic loss is opposite to the dielectric loss.The magnetic loss and dielectric loss synergistically promote the improvement of absorption performance of the material.In addition,the impedance matching area also firstly increases and then decreases as the temperature increases.The impedance area of the sample HEO-900 is relatively large,indicating that there are more electromagnetic waves incident on the interior of the material and the absorption efficiency increases. Conclusions The results indicated that oxygen vacancies were easily generated in(Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)CoxOy high-entropy ceramics due to the multivalent state and multiple transformations of element Co,which was conducive to electron transfer.The presence of multiphase structure and oxygen vacancies increased the dielectric loss of the material and the interface polarization and defect polarization of the system,thus significantly improving the absorption capacity of electromagnetic waves.This study found that the sample HEO-900 sintered at 900℃had the optimum absorption performance(i.e.,the RLmin value of-36.14 dB and an optimal bandwidth of 2.86 GHz at a matching thickness of 3.0 mm and a frequency of 9.37 GHz).关键词
高熵氧化物陶瓷/尖晶石结构/岩盐结构/介电损耗/电磁波吸收性能Key words
high-entropy oxide ceramics/spinel structure/rock salt structure/dielectric loss/electromagnetic wave absorption performance分类
化学化工引用本文复制引用
王中义,任玉美,杨帅,席通,郭晓琴,赵彪,张锐..尖晶石/岩盐型(Fe0.2Co0.2Ni0.2Cu0.2Zn0.2)CoxOy高熵陶瓷的制备与吸波性能[J].硅酸盐学报,2025,53(3):647-657,11.基金项目
国家自然科学基金项目(U21A2064) （U21A2064）
河南省自然科学基金重点项目(242300421188) （242300421188）
河南省航空材料与技术重点实验室开放基金(ZHKF-240104/05) （ZHKF-240104/05）
河南省高等学校重点科研项目(24A150045)资助. （24A150045）
