包壳管内壁表面螺旋波等离子体渗氮处理研究  

Study on Helical Wave Plasma Nitriding Treatment on the Surface of the Inner Wall of Cladding Tube

作　　者：刘满星 诸葛兰剑 吴雪梅[1] 金成刚 LIU Man-xing;ZHUGE Lan-jian;WU Xue-mei;JIN Cheng-gang(School of Physical Science and Technology, Soochow University, Suzhou 215006, China;Analysis and Testing Center,Soochow University, Suzhou 215006, China;Laboratory for Space Environment and Physical Sciences, Harbin Institute of Technology, Harbin 150001, China)

机构地区：[1]苏州大学物理科学与技术学院,江苏苏州215006 [2]苏州大学分析测试中心,江苏苏州215006 [3]哈尔滨工业大学空间环境与物质科学研究院,黑龙江哈尔滨150001

出　　处：《节能技术》2022年第2期130-135,共6页Energy Conservation Technology

摘　　要：核反应堆由于其苛刻的工作环境,面临着燃料与包壳管相互作用(包含机械和化学)等严重的材料科学问题。为了减少乃至阻止燃料的作用而又不牺牲包壳管的整体性,最实际的方法是在包壳管内表面涂覆硬度高、燃料扩散系数低的涂层。本文采用小口径(10 mm)、稳态、高通量N_(2)/Ar螺旋波等离子体在450℃下对细长316 L奥氏体不锈钢管的内壁表面进行渗氮处理。采用光学显微镜、扫描电子显微镜、X射线衍射仪、能量色散X射线光谱仪和显微硬度计表征了渗氮层的微观结构、厚度、表面形貌及其表面硬度性质。实验结果表明,渗氮层主要为膨胀奥氏体相γ_(N)相,并没有发现CrN和铁氮化合物的析出。经电感耦合等离子体(ICP)和螺旋波等离子体(HWP)处理后,渗氮层的显微硬度呈上升的趋势,但HWP渗氮(硬度高达1815 HV,厚度为23μm)处理后,不锈钢管内表面硬度是ICP渗氮的1.5倍,这归因于在HWP放电模式下,等离子体具有更高的N^(+)密度。考虑到易于在口径非常小的细长管中控制N_(2)等离子体放电,为实现细长管内壁表面渗氮开辟了一条新的途径。Because of the harsh working environment of nuclear reactors,they face serious material science problems such as the interaction between fuel and cladding tubes.In order to reduce or even prevent the influence of fuel without sacrificing the integrity of the cladding tube,the most practical method is to coat the inner surface of the cladding tube with a coating with high hardness and low fuel diffusion coefficient.A steady-state,high-flux N_(2)/Ar Helicon Wave Plasma(HWP)with very small-diameter(10 mm)was used to nitride the inner surface of the slender Austenitic Stainless Steel(ASS)316L tube at the temperatures of 450℃.The microstructure and thickness of the nitrided layers and morphology of the nitrided surfaces,as well as its surface hardness,were investigated using Optical Microscopy(OM),Scanning Electron Microscopy(SEM),X-ray Diffraction(XRD),and Energy Dispersive X-ray spectroscopy(EDX),and microhardness tester.The results confirmed that nitrided layer was main expanded austenite phaseγ_(N),and neither CrN nor iron nitrides was precipitated.Increasing trend in microhardness is observed in Inductive Coupled Plasma(ICP)and HWP modes,but the increase in HWP nitriding(up to HV 1820 with thickness of 14μm)is about 1.5 times greater than that achieved by ICP plasma nitriding,due to higher N^(+) ion density in HWP mode.Considering the easy control of N_(2) plasma discharge in the slender tube with very small diameter,our work opens up a new avenue for achieving high-yield nitirded layer insider the slender tube.

关 键 词：螺旋波等离子体 细长316L不锈钢管 管内表面渗氮 

分 类 号：TL352.22[核科学技术—核技术及应用]