首页|Thermodynamics aided design of hBN-capsulated diboride powders from novel nitrate precursors for high entropy ceramics

Thermodynamics aided design of hBN-capsulated diboride powders from novel nitrate precursors for high entropy ceramics

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Hexagonal BN-coated powders have been widely used in various engineering sectors,however,their pro-ductions are restricted by the complexity of gas-solid reactions.In this study,guided by thermodynamics,a novel approach to synthesize Layer-structured hexagonal BN(hBN)-coated high entropy diboride pow-ders in vacuum was developed,using metal salt Zr(NO3)4·5H2O,HfCl4,NbCl5,TaCl5,C16H36O4Ti,boric acid,and sucrose as raw materials.By adjusting the ratio of carbon to metal source(C/M),powders only consisting of two boride solid solutions and hBN were finally obtained,under an optimal process-ing condition of C/M=5.5 and synthesis temperature of 1400 ℃.Parts of hBN were found to coat on high-entropy metal diborides ceramic(HEB)particles,corresponding formation mechanism for core-shell structured powders was investigated,together with the liquid precursor assisted boro/carbothermal re-duction process.Starting from as-synthesized core-shell powders,(Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)B2-11 vol％hBN ceramics were densified at 1900 ℃ under 50 MPa without holding,with a high relative density of 97.3％.

High entropy borideBoro/carbothermal reductionSol-gelCore-shell powdersDensification

Hailing Yang、Ji Zou、Zhimin Xiong、Jingjing Liu、Weimin Wang、Zhengyi Fu

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State Key Laboratory of Advanced Technology for Materials Synthesis and Processing,Wuhan University of Technology,Wuhan 430070,China

Hubei Longzhong Laboratory,Xiangyang 441000,China

School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China

National Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Natural Science Foundation of ChinaNational Key R&D ProgrammerHubei Provincial Natural Science Foundation of ChinaIndependent Innovation Projects of the Hubei Longzhong Laboratory

52022072523320035197224352293373920602022021YFB3701400Distinguished Young Scholars 2022CFA0422022ZZ-10

2024

10.1016/j.jmst.2023.08.034

材料科学技术(英文版)
中国金属学会 中国材料研究学会 中国科学院金属研究所

材料科学技术(英文版)

CSTPCD
影响因子：0.657
ISSN：1005-0302
年,卷(期)：2024.178(11)
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