摘要
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%ZrO_(2)-1%CaCO_(3-x)%MnCO_(3)(MZCM_(x),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 ZrO_(2) and CaCO_(3) effectively inhibited excessive growth of MgO grains by formation of second phase,while addition of MnCO_(3) 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.
追求具有高介电强度的陶瓷介质材料,探究影响介电强度的内在因素,对选择合适的高功率微波传输器件介质窗材料、保证功率传输的可靠性具有重大的科学研究和工程应用价值。氧化镁(MgO)陶瓷具有高理论介电强度和低介电损耗的介电性能,在高功率微波传输器件应用方面潜力巨大,但其烧结温度过高,阻碍了设计与应用。本工作通过传统固相反应法制备了MgO-1%Zr O_(2)-1%CaCO_(3-x)%Mn CO_(3)(MZCM_(x),x=0、0.25、0.50、1.00、1.50,摩尔比)系列陶瓷,并对其相结构、形貌特征和介电性能等进行表征分析。研究发现:引入ZrO2和CaCO3形成了第二相,显著抑制了MgO晶粒的过分长大;添加Mn CO3促进了陶瓷烧结初期的晶界扩散过程,降低了陶瓷的晶粒生长激活能,从而有效降低了陶瓷烧结温度。最终在1350℃下烧结制备的MZCM1.00陶瓷获得了高介电强度和品质因数(Eb=92.3 k V/mm,Q×f=216642 GHz),同时具有低介电损耗(<0.03%)、低电容温度系数(20.3×10^(–6)℃^(–1),85℃)和相对接近于零的谐振频率温度系数(–12.54×10^(–6)℃^(–1))。本研究为高功率微波传输器件选择介质窗材料以及提升综合性能提供了一种简单有效且可满足实际生产应用的解决方案。
出处
《无机材料学报》
北大核心
2025年第1期97-103,共7页
Journal of Inorganic Materials
基金
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)。
