UN_(x)与O_(2)、H_(2)O、H_(2)的相容性  

Compatibility of UN_(x)With O_(2),H_(2)O and H_(2)

作　　者：陈守闯 钟火平 胡殷[2] 罗丽珠[2] 龙重[1] 苏斌[1] 白彬[1] 刘柯钊[1] CHEN Shou-chuang;ZHONG Huo-ping;HU Yin;LUO Li-zhu;LONG Zhong;SU Bin;BAI Bin;LIU Ke-zhao(Institute of Materials,China Academy of Engineering Physics,Mianyang 621907,China;Science and Technology on Surface Physics and Chemistry Laboratory,Mianyang 621907,China)

机构地区：[1]中国工程物理研究院材料研究所,四川绵阳621907 [2]表面物理与化学重点实验室,四川绵阳621907

出　　处：《核化学与放射化学》2024年第3期185-192,I0001,共9页Journal of Nuclear and Radiochemistry

摘　　要：U金属化学性质活泼,在环境中容易发生氧化、水解、氢蚀等反应,严重影响其物理化学性能。有很多方法被用于U表面的防腐蚀研究,其中最常用的方法之一是在表面形成一层能够有效隔断金属表面与外部气氛关联的UN_(x)(U_(2)N_(3+x)或UN)表面改性层。该表面层与外部环境直接接触,其与环境气氛,特别是气氛中的O2、H_(2)O、H_(2)等分子的相容性是决定改性层是否能够长期稳定存在并保持良好防腐蚀特性的关键因素。本文综述了UNx与O2、H_(2)O、H_(2)等的相容性,认为改性层的均匀性与完整性是长期防腐蚀的关键要素,氧化及水解过程中的N富集是一个值得关注的问题,水解过程中气相成分变化显著,需要深入研究。Uranium metal and alloys can be easily oxidized by the O-containing species such as O_(2)and H_(2)O,etc.in atmosphere.Furthermore,the existence of H_(2)may also accelerates the oxidation of uranium metal.To prevent the corrosion of these materials,many techniques,such as alloying,coating,surface recrystallization,surface modification,etc.were developed to prevent this material from oxidation.In the surface modification processes,such as ion implantation,plasma nitriding and pulsed laser nitriding,UNx(U2N3+x or UN)layers are always formed on the metal surfaces to prevent the contact of the metal surfaces with the surrounding atmospheres.Thus the compatibilities of the as-prepared UNx layers with the surrounding atmospheres,especially O_(2),H_(2)O and H_(2)molecules there,can play important role on the corrosion resistance of the modified layers,and thus are important topics in the nuclear industry.Here the compatibilities of UNx with O_(2),H_(2)O and H_(2)molecules are reviewed,respectively.From the previous results,it seems that the as-prepared UNx,neither U2N3+x nor UN layers can directly prevent the diffusion of O_(2)into the solid phase.Instead,the surface of the modified layers can be easily oxidized to form UO_(2)or UO_(2)Nx layers.For a UNx layer in which x is smaller than 1,it can be oxidized to a final product of UO_(2).However,under environmental temperature,for a layer in which x is no less than 1,only a thin layer(about several tens of nm)of UO_(2)can be formed on the layer surface.Moreover,a gradient layer in which the O content gradually decreases while the N content gradually increases from the surface to the deeper layer may effectively prevent the continuous diffusion of O into the substrate,and thus the modified layer presents excellent anticorrosion property against O_(2).However,the modified layers can not effectively prevent the diffusion of O_(2)under high temperature.For the hydrolysis process,the surface UO_(2)layers may restrain the hydrolysis of UNx under environmental temperature.However

关 键 词：UN UN_(x)改性层 氧化 水解 氢蚀 

分 类 号：TL211.3[核科学技术—核燃料循环与材料] TL178