Journal of Inorganic Materials ›› 2025, Vol. 40 ›› Issue (1): 97-103.DOI: 10.15541/jim20240214

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Sintering Behaviour and Dielectric Properties of MnCO3-doped MgO-based Ceramics

WANG Zhixiang1,2,3(), CHEN Ying2,3,4(), PANG Qingyang2,3, LI Xin2, WANG Genshui1,2,3,4()   

  1. 1. School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
    2. Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
    3. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
    4. The State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
  • Received:2024-04-25 Revised:2024-05-21 Published:2025-01-20 Online:2024-05-31
  • Contact: WANG Genshui, professor. E-mail: genshuiwang@mail.sic.ac.cn;
    CHEN Ying, associated professor. E-mail: chenying@mail.sic.ac.cn
  • About author:WANG Zhixiang (1999-), male, Master candidate. E-mail: wangzhixiang21@mails.ucas.ac.cn
  • Supported by:
    Student Training Program for Innovation and Entrepreneurship of Hangzhou Institute for Advanced Study, UCAS(CXCY20230305);Chinese Academy of Sciences Key Project(ZDRW-CN-2021-3-1-18)

Abstract:

Ceramic dielectric materials with high dielectric strength and mechanisms of their internal factors affecting dielectric strength are significantly valuable for industrial application, especially for selection of suitable dielectric materials for high-power microwave transmission devices and reliable power transmission. Pure magnesium oxide (MgO), a kind of ceramic dielectric material, possesses great application potential in high-power microwave transmission devices due to its high theoretical dielectric strength, low dielectric constant, and low dielectric loss properties, but its application is limited by high sintering temperature during preparation. This work presented the preparation of a new type of multiphase ceramics based on MgO, which was MgO-1%ZrO2-1%CaCO3-x%MnCO3 (MZCMx, x = 0, 0.25, 0.50, 1.00, 1.50, in molar), and their phase structures, morphological features, and dielectric properties were investigated. It was found that inclusion of ZrO2 and CaCO3 effectively inhibited excessive growth of MgO grains by formation of second phase, while addition of MnCO3 promoted the grain boundary diffusion process during the sintering process and reduced activation energy for the grain growth, resulting in a lower ceramic sintering temperature. Excellent performance, including high dielectric strength (Eb = 92.3 kV/mm) and quality factor (Q × f = 216642 GHz), simultaneously accompanying low dielectric loss (< 0.03%), low temperature coefficient of dielectric constant (20.3×10-6-1, 85 ℃) and resonance frequency (-12.54×10-6-1), was achieved in MZCM1.00 ceramics under a relatively low sintering temperature of 1350 ℃. This work offers an effective solution for selecting dielectric materials for high-power microwave transmission devices.

Key words: MgO ceramic, dielectric strength, sintering temperature, growth activation energy

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