J. Mater. Sci. Technol. ›› 2021, Vol. 77: 58-65.DOI: 10.1016/j.jmst.2020.09.047

• Research Article • Previous Articles     Next Articles

(Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B: A novel high-entropy monoboride with good electromagnetic interference shielding performance in K-band

Haiming Zhanga,b, Biao Zhaoc, Fu-Zhi Daia, Huimin Xianga, Zhili Zhangb,*(), Yanchun Zhoua,*()   

  1. aScience and Technology on Advanced Functional Composite Laboratory, Aerospace Research Institute of Materials & Processing Technology, No. 1 South Dahongmen Road, Beijing, 100076, China
    bSchool of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, 100044, China
    cHenan Key Laboratory of Aeronautical Materials and Application Technology, School of Material Science and Engineering, Zhengzhou University of Aeronautics, Zhengzhou, 450046, China
  • Received:2020-07-18 Revised:2020-09-22 Accepted:2020-09-27 Published:2021-06-30 Online:2020-11-16
  • Contact: Zhili Zhang,Yanchun Zhou
  • About author:yczhou@alum.imr.ac.cn (Y. Zhou).
    * E-mail addresses: zlzhang@bjtu.edu.cn (Z. Zhang),

Abstract:

A novel equimolar high-entropy (HE) transition metal monoboride, (Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B, was designed and prepared in powder and bulk form by high temperature elemental reaction method and spark plasma sintering (SPS) method, respectively. XRD analysis shows that HE (Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B possesses orthorhombic structure with Pnma space group. Through Rietveld refinement, the lattice parameters of HE (Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B are a = 5.6675, b = 2.9714, c = 4.2209 and the theoretical density is 6.95 g/cm3. The Vickers hardness and electrical conductivity of HE (Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B bulk with relative density of 90 % is 12.3 ± 0.5 GPa and 0.49 ± 0.04 × 106 S/m, respectively. Due to high electrical conductivity, HE (Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B bulk with 3.0 mm thickness displays superior EMI shielding performance in 18.0-26.5 GHz (K-band), and the average values of SET, SER, and SEA are 23.3 dB, 13.9 dB, and 9.4 dB, respectively. The EMI shielding mechanism of HE (Cr0.2Mn0.2Fe0.2Co0.2Mo0.2)B mainly results from reflection.

Key words: High-entropy ceramics, Transition metal monoboride, Electromagnetic interference (EMI) shielding, Mechanical properties, Electrical conductive ceramics