氮气环境下NBG-18核石墨表面类聚合物碳涂层的摩擦学性能研究  

Tribological properties of polymer like carbon coatings on NBG-18 nuclear graphite under nitrogen environment

作　　者：韩海 刘汇川 成金娟 陈新春 刘鹏霄[4] 戚威 汤贤 HAN Hai;LIU Huichuan;CHENG Jinjuan;CHEN Xinchun;LIU Pengxiao;QI Wei;TANG Xian(School of Nuclear Science and Technology,University of South China,Hengyang 421001,China;Jihua Laboratory,Foshan 528200,China;School of Mathematics and Physics,University of South China,Hengyang 421001,China;State Key Laboratory of Tribology in Advanced Equipment,Tsinghua University,Beijing 100084,China;National United Engineering Laboratory for Advanced Bearing Tribology,Henan University of Science and Technology,Luoyang 471023,China)

机构地区：[1]南华大学核科学技术学院,衡阳421001 [2]季华实验室,佛山528200 [3]南华大学数理学院,衡阳421001 [4]清华大学高端装备界面科学与技术全国重点实验室,北京100084 [5]河南科技大学高端轴承摩擦学技术与应用国家地方联合工程实验室,洛阳471023

出　　处：《核技术》2024年第10期135-145,共11页Nuclear Techniques

基　　金：国家自然科学基金(No.52205195);高端装备界面科学与技术全国重点实验室开放基金资助项目(No.SKLTKF22A03);湖南省科技创新计划资助项目(No.2021RC3105);湖南省自然科学基金面上项目(No.2023JJ30512);高端轴承摩擦学技术与应用国家地方联合工程实验室开放基金项目(No.202202)资助。

摘　　要：高温气冷堆中球形燃料元件在往复循环流通过程中存在摩擦磨损问题。采用高能量离子束沉积(Ion Beam Deposition,IBD)镀膜工艺在NBG-18核石墨表面沉积类聚合物碳(Polymer Like Carbon,PLC)涂层,以提升其表面力学与摩擦学性能。镀膜后纳米压痕测试NBG-18核石墨的硬度从0.44 GPa提高到4.16 GPa,提高845%;弹性模量从9.00 GPa提高到27.21 GPa,提高202%;在载荷2 N、滑动频率5 Hz的氮气环境下,TRB~3摩擦磨损试验机测试其摩擦系数(Coefficient of Friction,COF)从0.335 7降至0.006 5,降低98%;三维白光干涉仪表征其磨损率从3.71×10^(-3) mm^(3)·(N·m)^(-1)降至1.81×10^(-6) mm^(3)·(N·m)^(-1),降低3个数量级。摩擦诱导PLC涂层石墨化与惰性环境高含氢表面钝化悬挂碳键是实现核石墨超滑的主要机制,可为核石墨表面改性润滑技术发展提供重要的理论支持。[Background]Nuclear graphite coatings on the surfaces of spherical fuel elements in high-temperature gas-cooled reactors(HTGRs)exhibit a high friction coefficient and low wear resistance.The reciprocating movement of the fuel balls leads to significant friction among the spherical fuel elements and between these elements,the graphite bed,and other components.This friction generates a considerable amount of graphite dust,which poses a risk to the proper functioning of nuclear reactors.[Purpose]This study aims to address the issues of friction and wear experienced by nuclear graphite on the surface of spherical fuel elements in HTGR by utilizing surface modification technology to enhance the mechanical and tribological properties of NBG-18 nuclear graphite.[Methods]Firstly,NBG-18 graphite,sourced from SGL Group-The Carbon Company,Germany,was cut into blocks with dimensions of 20 mm×20 mm×5 mm,and a polymer-like carbon(PLC)coating was applied to NBG-18 nuclear graphite using a high-energy ion beam deposition(IBD)process with preprocessing of cleaning,sample loading,vacuuming,transition layer deposition,functional layer deposition,and sampling,resulting in a total coating thickness of approximately 400 nm.Subsequently,nanoindentation tests were conducted to determine the hardness and elastic modulus of the sample with a maximum load of 5 mN,while a high-load scratch tester was used to assess the film substrate adhesion of the coating.Then,the coefficient of friction(COF)of NBG-18 with the PLC coatings was examined in a nitrogen environment using a TRB3 friction tester at room temperature with specific testing parameters set for normal loads and sliding frequencies to identify the optimal conditions.Various analyses,including ultra-depth field microscopy,white light interferometry,and Raman spectrometry,were employed to study the microstructure,wear rate,and friction interface characteristics of the coated samples.Finally,comparisons were made between the surface morphology,mechanical properties,and tribological pro

关 键 词：核石墨 类聚合物碳涂层 氮气 摩擦学性能 表面力学性能 离子束沉积 

分 类 号：TL35[核科学技术—核技术及应用]