摘要
在大力发展航空业的新形势下,航空发动机紧固件的咬死失效问题逐渐成为航空领域的关注焦点。但是由于航空紧固件面临应力、高温、微动等苛刻工况,在工作过程中,表面银润滑涂层会出现形变、剥落等失效形式,这是提高航空发动机发展水平必须要解决的难题。系统阐述苛刻工况下航空发动机紧固件中存在的微动磨损、磨粒磨损、氧化磨损、粘着磨损4种主要磨损失效形式,对未涂覆保护涂层的螺栓表面以及对涂覆银润滑涂层的涂层表面产生的影响,对比电镀工艺和磁控溅射工艺制备的高温环境用银涂层在硬度、结合力等方面的不同,简述几种可以提高银涂层润滑能力的复合增强涂层制备技术,综述用于高温环境中紧固件保护的高硬度特性和高温特种氧化替代涂层。总结现用航空发动机失效紧固件上银涂层失效分析和现有研究结论,得出实际使用过程中银涂层软化和银的高扩散率是导致涂层失效的主要原因,对涂层保护技术在航空发动机紧固件中的应用提出建议与展望。主要提出了高温下银涂层失效问题的可能解决方法。
With the rapid development of the aerospace industry,the failure of aero-engine fasteners has increasingly become focal point in this field.Frequent fastener failures significantly hinder the progress of aero-engine development.Electroplated silver coatings are typically employed to satisfy the high demands for specificity and reliability in aero-engine fasteners.However,due to harsh operating conditions,such as high stress,high temperature,and micromotion,the silver coating on the surface of aero-engine fasteners can fail in the form of deformation and peeling during relative motion with structural materials or after high temperatures.Addressing this issue is crucial for improving the development level of aero-engines.In this study,the current state of silver coating applications is introduced,problems in silver coating application are summarized,and potential solutions are proposed from the perspective of preparation processes and coating materials.First,the development status of aero-engine fasteners are presented domestically and internationally.Silver coating is the most common protective coating for aero-engine fasteners,providing a certain level of lubrication.However,as technology advances and fastener working environments worsen,silver coating failures have become more frequent and demand urgent attention.Next,the specific effects of the four main wear failure modes(fretting wear,abrasive wear,oxidative wear,and adhesive wear)are systematically described on the uncoated bolt surface and surface coated with a silver lubrication coating under high temperatures and other harsh conditions.These wear modes occur because the coating's lubrication performance requires further improvement when the engine operates under adverse conditions such as high stress,high temperature,and slight motion.The hardness and binding strength of silver coatings prepared via electroplating and magnetron sputtering are compared in high-temperature environments.Currently,electroplating is the most common method for preparing single silver coatings,while magnetron sputtering,a widely used coating preparation process,can also be employed to produce silver coatings.The comparison reveals that the magnetron sputtering process results in silver coatings with higher hardness and stronger binding at high temperatures.Furthermore,several preparation technologies are briefly discussed for composite-enhanced coatings that can improve the lubrication ability of silver coatings,including the addition of reinforcement materials,lubricants,and lubricating material blending.The addition of reinforcement materials can enhance the coating's basic performance,while incorporating lubricating grease can improve the coating's working environment,and blending lubricating materials can extend the coating's working temperature range.The hardness properties of fastener protection in high-temperature environments and special oxidation substitute coatings at high temperatures are reviewed.High hardness aids the coating in resisting excessive deformation after softening at high temperatures.High-temperature special oxidation coatings effectively utilize the characteristics of the oxide film formed on the material surface at high temperatures,protecting the substrate with a lubricating or high-hardness oxide film.Additionally,by analyzing the failure of silver coatings on existing aero-engine fasteners and reviewing the research conclusions of domestic and international scholars,we determine that the softening of the silver coating and high diffusivity of silver are the main reasons for coating failure during actual applications.Additionally,suggestions are provided for the application of coating protection technology in aero-engine fasteners,including failure analysis methods,preparation technology,and material selection.
作者
刘燕
李国政
贾丹
詹胜鹏
李文轩
段海涛
LIU Yan;LI Guozheng;JIA Dan;ZHAN Shengpeng;LI Wenxuan;DUAN Haitao(Tianjin Key Laboratory of Fastening Technology,Tianjin 300300,China;State Key Laboratory of Special Surface Protection Materials and Application Technology,Wuhan Institute of Materials Protection,Wuhan 430030,China;Hubei Longzhong Laboratory,Xiangyang 441000,China)
出处
《中国表面工程》
EI
CAS
CSCD
北大核心
2023年第4期21-35,共15页
China Surface Engineering
基金
国家重点研发计划(2021YFF0601702)
国家自然科学基金(51975421)
天津市紧固连接技术企业重点实验室开放基金(TKLF2022-02-A-03)资助项目。
关键词
银涂层技术
紧固件
高温
磨损失效
silver coating technology
fasteners
high temperature
wear loss efficiency
