摘要
针对铅冷快堆环境下铅铋共晶腐蚀碳化硅(SiC)问题,采用第一性原理计算方法,研究了氧(O)、铅(Pb)、铋(Bi)原子在SiC表面的吸附和腐蚀行为,以及O原子对Pb、Bi原子吸附和腐蚀的影响。通过表面能考察了几种典型低指数晶面的稳定性。结果显示,晶面的稳定性排序为(100)^(Si)<(100)^(C)<(111)^(Si)<(111)^(C)<(110)。基于最稳定SiC(110)表面,考察了O、Pb、Bi原子的吸附行为。结果表明,SiC(110)表面上Pb和Bi原子最稳定的吸附位点是C原子中空位(H_(C)),O原子最稳定的吸附位点是Si-C桥位(B_(SiC)),且O比Pb和Bi更易吸附。O原子吸附在SiC表面后,能够促进近邻Pb、Bi原子的吸附。同时,O、Pb、Bi都能促进表面C和Si原子溶解,其中表面C更易溶解,且O吸附会促进Pb、Bi对SiC表面的溶解腐蚀。
Lead-cooled fast reactor(LFR)is one of the most promising fourth-generation nuclear reactors.However,when the liquid metal coolant,lead-bismuth eutectic(LBE)is in contact with the structural materials in the reactor core,liquid metal atoms and oxygen atoms can cause oxidative corrosion and dissolution of the structural materials.The corrosion process is closely related to the composition,microstructure and operational environment of the materials.Therefore,compatibility between LBE and structural materials is critical for the safe operation of lead-cooled fast reactors.Cubic silicon carbide(3C-SiC)exhibits excellent properties such as low neutron activation,resistance to hightemperature creep,high-temperature oxidation,and high thermal conductivity,therefore was taken as a promising candidate material for key structural components in next-generation advanced nuclear energy systems.As in contact with LBE,SiC generally demonstrates better corrosion resistance than steel under certain experimental conditions,such as in oxygen controlled LBE or low temperature.However,SiC still exhibits different corrosion behaviors under saturated oxygen and irradiation.The adsorption and corrosion behaviors of oxygen(O),lead(Pb),and bismuth(Bi)atoms on the surface of SiC in a lead-cooled fast reactor environment using first-principles calculations were investigated in this study,and the effects of oxygen on the adsorption of Pb and Bi as well as the corrosion of SiC surface were also examined.The stability of several typical low-index crystal surfaces was firstly evaluated based on their surface energy,revealing that the order of crystal surface stability is as follows:(100)^(Si)<(100)^(C)<(111)^(Si)<(111)^(C)<(110).The most stable SiC surface for further analysis was determined to be the(110)surface.Adsorption behaviors of O,Pb,and Bi atoms on this surface were then investigated.Results indicate that Pb and Bi atoms preferentially adsorb at carbon hollow sites(H_(C)),while O atoms favor adsorption at silicon-carbon bridge sites(B_(SiC)).Furthermore,O atoms exhibit stronger adsorption tendencies compared to Pb and Bi.The oxygen adsorbed on the SiC surface was found to enhance the adsorption of nearby Pb and Bi atoms.Additionally,all three elements,O,Pb and Bi promote the dissolution of carbon and silicon atoms at the surface.Importantly,C atoms are more prone to dissolution than silicon atoms,and the presence of oxygen significantly enhances the dissolution corrosion caused by Pb and Bi on the SiC surface.These findings provide fundamental insights into the mechanisms underlying the interaction between LBE and SiC,offering valuable guidance for the development of advanced nuclear energy systems with enhanced safety and reliability.
作者
李琦琦
张艳革
李祥艳
许依春
吴学邦
刘长松
LI Qiqi;ZHANG Yange;LI Xiangyan;XU Yichun;WU Xuebang;LIU Changsong(University of Science and Technology of China,Hefei 230026,China;Hefei Institutes of Physical Science,Chinese Academy of Sciences,Hefei 230031,China)
出处
《原子能科学技术》
北大核心
2025年第12期2688-2696,共9页
Atomic Energy Science and Technology
基金
国家重点研发计划(2023YFA1609000)
国家自然科学基金(52071314,12275319,12475272)。
关键词
碳化硅
表面能
吸附能
空位形成能
第一性原理
silicon carbide
surface energy
adsorption energy
vacancy formation energy
first-principle
