斜撑式超越离合器用Cr_7C_3涂层和GCr15基体的磨损行为研究  

Wear Behavior of Cr_7C_3 Coating and GCr15 Substrate for Sprag Overrunning Clutch

作　　者：雷美娟 田凌[1,2] 石金大 刘钡钡 LEI Mei-juan;TIAN Ling;SHI Jin-da;LIU Bei-bei(Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China;Beijing Key Lab of Precision/Ultra-precision Manufacturing Equipment and Control,Tsinghua University,Beijing 100084,China;Institute of Army Aviation,Beijing 101121,China)

机构地区：[1]清华大学机械工程系,北京100084 [2]精密超精密制造装备及控制北京市重点实验室,北京100084 [3]陆军航空兵研究所,北京101121

出　　处：《表面技术》2018年第8期90-97,共8页Surface Technology

基　　金：国家自然科学基金(51175287)~~

摘　　要：目的研究斜撑式超越离合器用Cr_7C_3涂层和GCr15基体与合金钢9310对磨时的摩擦性能和磨损机理。方法在GCr15基体上利用化学气相沉积技术制备Cr_7C_3涂层样件。利用带有能谱分析仪的扫描电镜、X射线衍射仪和纳米压痕仪分析测量涂层的厚度和物相组成以及有无Cr_7C_3涂层时样件的显微硬度。利用球-盘接触式SRV-4高温摩擦磨损试验机考察Cr_7C_3涂层和GCr15基体的摩擦磨损性能。采用三维白光干涉形貌仪和扫描电镜系统地分析材料的磨痕情况。结果 Cr_7C_3涂层厚度约为4~6μm,主要包含Cr_7C_3和(Cr,Fe)7C3两种相。涂层的平均显微硬度为22.709 GPa,约为GCr15基体(11.198 GPa)的2倍。在试验参数下,Cr_7C_3涂层的摩擦系数为0.18~0.24,GCr15基体的摩擦系数为0.15~0.20。当滑动速度为60 mm/s,法向载荷为20 N^60 N时,GCr15的磨损率约是Cr_7C_3涂层的4~6倍;当滑动速度为100 mm/s时,GCr15基体的磨损率约是Cr_7C_3涂层的7~11倍。当滑动速度为100 mm/s,法向载荷为60 N时,GCr15基体的磨损机理为典型的犁沟磨损。Cr_7C_3涂层主要为犁沟磨损和一定的疲劳磨损。结论 Cr_7C_3涂层具有较高的硬度和良好的耐磨性,有助于改善基体的耐磨性能和斜撑式超越离合器的使用性能。The work aims to study frication property and wear mechanism of Cr7C3 coating or GCr15 substrate being rubbed with 9310 alloy steel for sprag overrunning clutch.Cr7C3 coating sample was prepared on GCr15 substrate by adopting chemical vapor deposition technology.The thickness and phase composition of Cr7C3 coating and microhardness of both samples(with and without Cr7C3 coating)were analyzed by scanning electron microscope(SEM)(with EDS analysis),X-ray diffractometer(XRD)and nano-indenter.Friction and wear properties of Cr7C3 coating and GCr15 substrate were investigated with ball-on-disk SRV-4 high temperature tribotester.Wear scar conditions of the materials were characterized systematically with 3D white light interferometer surface profiler and SEM.It was calculated that the thickness of Cr7C3 coating was about 4~6μm.And it was mainly composed of phase Cr7C3 and phase(Cr,Fe)7C3.Average surface microhardness of the Cr7C3 coating was 22.709 GPa,nearly twice that of GCr15 substrate(11.198 GPa).Under experimental parameters,frication coefficient of the Cr7C3 coating ranged between 0.18~0.24 while that of GCr15 substrate ranged between 0.15~0.20.Wear rate of GCr15 was about 4~6 times that of Cr7C3 coating at the sliding speed of 60 mm/s and normal load of 20~60 N,but 7~11 times that of Cr7C3 coating at the sliding speed of 100 mm/s.The wear mechanism of GCr15 substrate was typical furrow wear,and that of Cr7C3 coating was mainly furrow wear and fatigue wear at the sliding speed of 100 mm/s and normal load of 60 N.Cr7C3 coating has high microhardness and excellent wear resistance,which can contribute to better wear resistance of the substrate and higher usability of sprag overrunning clutch.

关 键 词：Cr7C3涂层 GCr15基体 磨损机理 耐磨性 显微硬度 斜撑式超越离合器 

分 类 号：TG174.444[金属学及工艺—金属表面处理]