摘要
以聚硅氮烷和四(二甲胺)锆为原料,利用单源先驱体法制备SiZrCN纳米复相陶瓷。研究先驱体的合成路径、聚合物-陶瓷转变过程及陶瓷高温结构演变规律。研究结果表明,通过对先驱体改性可精确调控陶瓷中的Zr含量,并提高陶瓷产率。1 100℃热解后的SiZrCN陶瓷为无定形,当热处理温度≥1 500℃时,形成以Si3N4为主相、纳米ZrCN颗粒和自由碳均匀分布于其中的纳米复相陶瓷。Zr的加入抑制了热处理过程中含氮相的碳热还原反应,显著提高了陶瓷的高温热稳定性,1 600℃热处理的SiZrCN陶瓷的质量损失率仅为SiCN陶瓷的1/3。通过改变Zr含量和微观结构对SiZrCN陶瓷的介电参数进行了调控,并获得了优异的吸波性能。其中,当15SiZrCN-1500陶瓷的厚度为1.8 mm时,最小反射损耗为-61.02 dB,有效吸收带宽可达4.56 GHz。纳米ZrCN和自由碳形成的异质界面极化和缺陷偶极子极化以及所构成的导电网络是SiZrCN陶瓷具有优异吸波性能的主要原因。
SiZrCN nanocomposite ceramics were successfully prepared by using a single-source precursor synthesized from polysilazane and tetrakis(dimethylamido)zirconium.The synthesis route for the precursors,the polymer-ceramic conversion process,and structural evolution in ceramics at high temperatures were studied.The results indicate that modification of precursor can precisely control Zr content in ceramics and improve ceramic yield.After pyrolysis at 1100℃,SiZrCN ceramics are amorphous.When the heat treatment temperature is equal to or higher than 1500℃,SiZrCN ceramics are converted into nanocomposite ceramics that contain Si3N4 as the main phase,and evenly distribute ZrCN nanoparticles and free carbon.The introduction of Zr inhibits the carbothermal reduction of nitrogen-containing phases during the heat treatment,which significantly improves the high temperature stability of the ceramics(the mass loss proportion of SiZrCN ceramic at 1600℃is only 1/3 of that of SiCN ceramic).The dielectric parameters of SiZrCN ceramics are regulated by changing Zr contents and microstructures of the ceramics,leading to excellent electromagnetic wave absorbing performance.Among SiZrCN ceramics,the 15SiZrCN-1500 ceramic has a minimum reflection loss of−61.02 dB and an effective electromagnetic wave absorption band width of 4.56 GHz at a thickness of 1.8 mm.The hetero-interfacial polarization,defect-induced dipole polarization,the conductive network formed by ZrCN nanoparticles and free carbon are the main reasons for the excellent electromagnetic wave absorbing performance of SiZrCN ceramics.
作者
张振宇
杨金灿
卢丽
文统辉
王雅雷
文青波
熊翔
ZHANG Zhenyu;YANG Jincan;LU Li;WEN Tonghui;WANG Yalei;WEN Qingbo;XIONG Xiang(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)
出处
《中南大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2024年第8期2910-2924,共15页
Journal of Central South University:Science and Technology
基金
国家自然科学基金青年科学基金资助项目(52102085)
国家自然科学基金优秀青年科学基金资助项目(2021)
中南大学粉末冶金国家重点实验室自主课题(621022335)。
关键词
先驱体陶瓷
微观结构
介电
电磁吸波
polymer derived ceramics
microstructure
dielectric
electromagnetic wave absorption
作者简介
通信作者:文青波,博士,教授,从事聚合物先驱体陶瓷及其结构与功能应用研究,E-mail:wentsingbo@csu.edu.cn。
