Isotropic hexagonal boron nitride ceramics with high thermal conductivity and strengthOA
The conventional fabrication of bulk van der Waals materials,such as hexagonal boron nitride(hBN),faces significant challenges in sintering powder into structurally isotropic bulk forms.hBN has attracted considerable attention for applications under extreme conditions because of its excellent thermal stability,oxidation resistance,and electrical insulation.However,its strongly anisotropic layered structure typically results in poor mechanical performance and limited isotropy in bulk forms.In this study,we report the fabrication of isotropic hBN ceramics through the controlled transformation of cubic BN(cBN)powders under spark plasma sintering conditions.The coexistence of randomly oriented hBN sheets and residual turbostratic BN(tBN)phases produces an isotropic microstructure that yields balanced mechanical and thermal properties.The ceramics exhibit a compressive strength of~130 MPa and a thermal conductivity of~77 W·m^(-1)·K^(-1),nearly independent of the measurement direction.This thermally driven cBN→hBN transformation provides a new strategy for tailoring the microstructure and overcoming the intrinsic anisotropy of layered ceramics,paving the way for advanced insulating components in harsh environments.
Meng Hu;Wenyuan Zhang;Jixiang Zhang;Mengdong Ma;Penghui Li;Shuai Chen;Yingju Wu;Yan Zhong;Julong He;Ralf Riedel;Jianning Ding
School of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,ChinaSchool of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,ChinaSchool of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,ChinaCenter for High Pressure Science,State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,ChinaCenter for High Pressure Science,State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,ChinaCenter for High Pressure Science,State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,ChinaMechano-X Institute,Applied Mechanics Laboratory,Department of Engineering Mechanics,Tsinghua University,Beijing 100084,ChinaSchool of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,ChinaCenter for High Pressure Science,State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao 066004,ChinaInstitute of Materials Science,Technical University of Darmstadt,Darmstadt 64287,GermanySchool of Mechanical Engineering,Jiangsu University,Zhenjiang 212013,China
化学化工
hexagonal boron nitride(hBN)ceramicsstructurally isotropicphase transformationthermal conductivitymechanical properties
《Journal of Advanced Ceramics》 2026 (4)
P.251-261,11
supported by the National Natural Science Foundation of China(Nos.52302063,92463305,52302048,52202071,and 52572075)the China Postdoctoral Science Foundation(No.2023M741879)the Beijing Natural Science Foundation(No.JR25004)the National Postdoctoral Program for Innovative Talents(No.BX20240307)the Fundamental and Interdisciplinary Disciplines Breakthrough Plan of the Ministry of Education of China(No.JYB2025XDXM403)the S&T Program of Hebei(Nos.24461901D and 25361501D)the General programs of China Postdoctoral fund(No.2024M762819)the Postdoctoral Fellowship Program of China Postdoctoral Science Foundation(No.GZB20240633)the Natural Science Foundation of Hebei(No.E2025203213)the Hebei Province high-level talent funding(No.HY2025050006).
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