摘要
闪烧技术是一种温度场与电场耦合的烧结技术,具有低温快速传质的特性,在高熵陶瓷的合成上具有显著的优势。本研究通过闪烧法合成了相对致密的高熵氧化物陶瓷(MgCoNiCuZn)O,并与传统烧结试样的性能进行了对比。在室温,电场强度为50 V/cm,电流密度为300 mA/mm^(2)条件下闪烧,物相转变的时间仅为10 s。闪烧试样最高相对密度为94%,比传统烧结试样最高密度提高了22.8%。闪烧试样的最高硬度5.05GPa,比传统烧结试样高3.95 GPa。当频率<2Hz时,闪烧试样的介电常数比传统烧结试样高一个数量级。闪烧试样性能的提高,一方面与临界电场加速传质,提高材料致密度有关;另一方面与临界电场引入额外的缺陷有关。
Flash sintering is a sintering technology coupled with temperature field and electric field, with characteristics of rapid mass transfer at low temperature, showing significant advantages in the synthesis of high entropy ceramics. In this study, relatively dense high entropy oxide ceramic(MgCoNiCuZn)O was synthesized by flash sintering, which properties were compared with those of conventional sintered samples. Under flash sintering condition of room temperature, the electric field intensity of 50 V/cm and the current density of 300 mA/mm^(2), the time of phase transformation is only 10 s. The maximum relative density of flash sintered sample is 94%, which is 22.8%higher than that of conventional sintered sample. The maximum hardness of flash sintered sample is 5.05 GPa, which is 3.95 GPa higher than that of conventional sintered sample. When the frequency is lower than 2 Hz, the dielectric constant of flash sintering sample is one order of magnitude higher than that of conventional sintered sample. The property improvement of flash sintered samples is attributed to the acceleration of mass transfer by the critical electric field to increase the material density, and the extra defects introduced by the critical electric field.
作者
李汪国
刘佃光
王珂玮
马百胜
刘金铃
LI Wangguo;LIU Dianguang;WANG Kewei;MA Baisheng;LIU Jinling(School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China;School of MechanicalEngineering,Dongguan University of Technology,Dongguan 523808,China;School of Mechanics and Aerospace Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《无机材料学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第12期1289-1294,共6页
Journal of Inorganic Materials
基金
国家自然科学基金重点项目(51732009)
中央高校基本科研业务费专项资金(2682022ZTPY076)。
关键词
高熵氧化物
闪烧
相变
介电常数
high entropy oxide ceramics
flash sintering
phase transformation
dielectric constant
