Enhanced oxidation resistance of high-entropy diborides by multicomponent synergistic effects  

多组元协同效应提升高熵二硼化物抗氧化性能

作　　者：Zhongyu Tang Zihao Wen Lei Zhuang Hulei Yu Yanhui Chu 唐忠宇;文子豪;庄磊;俞呼雷;褚衍辉(School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]School of Materials Science and Engineering,South China University of Technology,Guangzhou 510641,China

出　　处：《Science China Materials》2024年第10期3392-3400,共9页中国科学（材料科学）（英文版）

基　　金：the financial support from the National Key Research and Development Program of China(2021YFA0715801);the National Natural Science Foundation of China(52122204)。

摘　　要：Oxidation resistance is critical for high-entropy diborides(HEBs)to be used as thermal structural components under oxygen-containing high-temperature environments.Here,we successfully realize the exploitation of(Zr,Ta,Cr,W)B2 HEBs with superior oxidation resistance by comprehensively screening their compositions.To be specific,21 kinds of HEB-xTM(x=0–25 mol%,TM=Zr,Ta,Cr,and W)samples are fabricated via an ultrafast high-temperature sintering technique.The as-fabricated HEB-5Cr samples show the best oxidation resistance at 1673 K among all the samples.Subsquent oxidation investigations further confirm the as-fabricated HEB-5Cr samples possess superior oxidation resistance with the parabolic oxidation behavior across 1473–1773 K.Such superior oxidation resistance is believed to result from the multi-component synergistic effects.Particularly,the Ta^(5+)and W^(4+)cations with high ionic field strengths can promote the formation of 4B–O–4B linkages between[BO4]tetrahedrons by charge balance,which can stabilize the threedimensional skeletal structure of B_(2)O_(3)glass and consequently result in an improved viscosity of the B_(2)O_(3)glassy layer.In addition,the ZrO_(2)and Cr_(2)O_(3)with high melting points can dissolve into the B_(2)O_(3)glass to increase its glass transition temperature,leading to an enhanced viscosity of the B_(2)O_(3)glassy layer.优异的高温抗氧化性能是高熵二硼化物(HEBs)作为热结构材料使用的重要前提.本文通过对(Zr,Ta,Cr,W)B2体系进行组分筛选,成功开发了具有优异抗氧化性能的HEBs材料.具体地,我们首先通过超快超高温烧结技术制备了21种HEBs-xTM(x=0–25 mol%,TM=Zr,Ta,Cr,和W)试样,随后对所制备HEBs试样的抗氧化性能进行了测试表征.研究发现,相比于其他试样,HEB-5Cr样品在1673 K温度下表现出最佳的抗氧化性能;在随后的1473–1773 K等温氧化过程中,其氧化行为被证实遵循抛物线规律,说明其具有优异的抗氧化性能.这主要归因于多组元协同效应,即高离子场强的Ta^(5+)和W^(4+)可以通过平衡电荷促进[BO4]四面体之间4B–O–4B键的形成,稳定B_(2)O_(3)玻璃的三维骨架结构,提高B_(2)O_(3)玻璃层的粘度;而高熔点的ZrO_(2)和Cr_(2)O_(3)复杂氧化物则可以溶解到B_(2)O_(3)玻璃中,增加其玻璃态转变温度,也可以提高B_(2)O_(3)玻璃层的粘度.

关 键 词：high-entropy diborides composition screening oxidation resistance synergistic effects 

分 类 号：TQ174.1[化学工程—陶瓷工业]