Cr coatings,as protective coatings of Zr-alloy fuel claddings,inevitably suffer from irradiation damage before they would possibly run into the accident condition.This study evaluates the radiation and oxidation toler...Cr coatings,as protective coatings of Zr-alloy fuel claddings,inevitably suffer from irradiation damage before they would possibly run into the accident condition.This study evaluates the radiation and oxidation tolerance of three Cr-based coatings with different microstructures(Cr,CrAlSi,and CrAlSiN)through He2+ion irradiation and 1200℃ steam oxidation.The Cr and CrAlSi coatings experienced significant structural degradation,characterized by He bubble aggregation and amplified Kirkendall effects at elevated temperatures.In contrast,the irradiated CrAlSiN coating maintained structural integrity without measurable irradiation hardening.Following annealing at 800℃ for 30 min,approximately 40%of injected He atoms were released,indicating a“self-healing”mechanism.The mechanism is attributed to uniformly distributed,low-density channels that act as sinks and release paths for irradiation-induced defects.Density functional theory simulations suggest that N atoms promote significant rearrangement of ions surrounding the free volume,inhibiting the formation of sites capable of trapping He atoms.Moreover,the CrAlSiN coating exhibited superior oxidation resistance compared to the Cr and CrAlSi coatings,even under high-temperature steam conditions.Notably,the irradiated CrAlSiN sample displayed a significantly thinner oxide scale compared to the pristine one(almost half),owing to a more protective oxide scale and rapid outward diffusion of Cr,Al,and Si through nanochannel veins.These findings illuminate the effects of structure and composition on irradiation and oxidation behavior in Cr-based coatings,offering insights for developing new-generation accident-tolerance fuel coatings for Zr-alloy claddings.展开更多
Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M...Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.展开更多
MXenes,a class of 2-dimensional transition metal carbides and nitrides,have garnered important attention due to their remarkable electrical and thermal conductivity,high photothermal conversion efficiency,and multifun...MXenes,a class of 2-dimensional transition metal carbides and nitrides,have garnered important attention due to their remarkable electrical and thermal conductivity,high photothermal conversion efficiency,and multifunctionality.This review explores the potential of MXene materials in various thermal applications,including thermal energy storage,heat dissipation in electronic devices,and the mitigation of electromagnetic interference in wearable technologies.Recent advancements in MXene composites,such as MXene/bacterial cellulose aerogel films and MXene/polymer composites,have demonstrated enhanced performance in phase change thermal storage and electromagnetic interference shielding,underscoring their versatility and effectiveness.Although notable progress has been made,challenges remain,including the need for a deeper understanding of photothermal conversion mechanisms,improvements in mechanical properties,exploration of diverse MXene types,and the development of sustainable synthesis methods.This paper discusses these aspects and outlines future research directions,emphasizing the growing importance of MXenes in addressing energy efficiency,health,and safety concerns in modern applications.展开更多
基金supported by the National Natu-ral Science Foundation of China(No.U2230126)the Natural Science Foundation of Zhejiang Province(No.LZ23E010001)+1 种基金This work was co-funded by the European Union under the Project Robotics and Advanced Industrial Production(Reg.No.CZ.02.01.01/00/22_008/0004590)supported by the Ministry of Education,Youth and Sports of the Czech Repub-lic through the e-INFRA CZ grant number ID:90140.Access to the computational infrastructure of the OP VVV funded Project No.CZ.02.1.01/0.0/0.0/16_019/0000765“Research Center for Informat-ics”and the use of the VESTA software[https://doi.org/10.1107/S0021889808012016]are also acknowledged.The authors thank the staffof HIRFL for the help with the irradiation experiment and the support of the Sharing Service Platform of CAS Large Re-search Infrastructures(2022-HIRFL-ZD-002017)。
文摘Cr coatings,as protective coatings of Zr-alloy fuel claddings,inevitably suffer from irradiation damage before they would possibly run into the accident condition.This study evaluates the radiation and oxidation tolerance of three Cr-based coatings with different microstructures(Cr,CrAlSi,and CrAlSiN)through He2+ion irradiation and 1200℃ steam oxidation.The Cr and CrAlSi coatings experienced significant structural degradation,characterized by He bubble aggregation and amplified Kirkendall effects at elevated temperatures.In contrast,the irradiated CrAlSiN coating maintained structural integrity without measurable irradiation hardening.Following annealing at 800℃ for 30 min,approximately 40%of injected He atoms were released,indicating a“self-healing”mechanism.The mechanism is attributed to uniformly distributed,low-density channels that act as sinks and release paths for irradiation-induced defects.Density functional theory simulations suggest that N atoms promote significant rearrangement of ions surrounding the free volume,inhibiting the formation of sites capable of trapping He atoms.Moreover,the CrAlSiN coating exhibited superior oxidation resistance compared to the Cr and CrAlSi coatings,even under high-temperature steam conditions.Notably,the irradiated CrAlSiN sample displayed a significantly thinner oxide scale compared to the pristine one(almost half),owing to a more protective oxide scale and rapid outward diffusion of Cr,Al,and Si through nanochannel veins.These findings illuminate the effects of structure and composition on irradiation and oxidation behavior in Cr-based coatings,offering insights for developing new-generation accident-tolerance fuel coatings for Zr-alloy claddings.
基金Project supported by the Doctoral Research Fund of Southwest University of Science and Technology(Grant No.20zx7104)the Sichuan Science and Technology Program(Grant No.2020ZYD055)the National Natural Science Foundation of China(Grant Nos.11905206 and 12075194)。
文摘Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C-M_(t)C composite ceramic was prepared by hot press sintering,with the Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2)C high-entropy carbide as the main phase.Secondary phase M_(x)C(M=Ti,Zr,Hf,Nb,Ta) was found to be distributed relatively uniform in the composite ceramic.The oxidation behavior of the ceramic was examined after exposure to 923 K and 1173 K.Morphology of the surface and cross sections of all oxidation samples were observed.The characteristics of the oxidation behavior of the high-entropy carbide and the secondary phase M_(x)C were compared and analyzed.The secondary phases(such as Ti-rich carbide or Hf-rich carbide) in the material were seriously oxidized at 923 K and 1173 K,which reflects the superior oxidation performance of the high-entropy carbide.The nano high-entropy oxides with Ti,Zr,Hf,Nb,Ta,and O elements were discovered by oxidation of the composite ceramic.This research will help deepen the understanding of the oxidation mechanism of high-entropy carbide and composite ceramic.
基金supported by the National Natural Science Foundation of China(Grant Nos.U23A2093 and 12375279)the High-Level Talents Special Support Program of Zhejiang Province(2022R51007)+1 种基金the Ningbo Top-talent Team Program,and the Youth Science and Technology Innovation Leading Talent Project of NingboK.L.gratefully acknowledges financial support from Anglo American Resources Trading(China)Co.,Ltd.
文摘MXenes,a class of 2-dimensional transition metal carbides and nitrides,have garnered important attention due to their remarkable electrical and thermal conductivity,high photothermal conversion efficiency,and multifunctionality.This review explores the potential of MXene materials in various thermal applications,including thermal energy storage,heat dissipation in electronic devices,and the mitigation of electromagnetic interference in wearable technologies.Recent advancements in MXene composites,such as MXene/bacterial cellulose aerogel films and MXene/polymer composites,have demonstrated enhanced performance in phase change thermal storage and electromagnetic interference shielding,underscoring their versatility and effectiveness.Although notable progress has been made,challenges remain,including the need for a deeper understanding of photothermal conversion mechanisms,improvements in mechanical properties,exploration of diverse MXene types,and the development of sustainable synthesis methods.This paper discusses these aspects and outlines future research directions,emphasizing the growing importance of MXenes in addressing energy efficiency,health,and safety concerns in modern applications.
