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...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.展开更多
基金the financial support from the National Key Research and Development Program of China(2021YFA0715801)the National Natural Science Foundation of China(52122204)。
文摘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.
基金supported by the National Key Research and Development Program of China(2022YFB3708600)the National Natural Science Foundation of China(52122204 and 51972116)Guangzhou Basic and Applied Basic Research Foundation(202201010632).
