活塞环表面Cr／CrN纳米多层膜的微观结构与摩擦学性能

Microstructure and tribological property of Cr/CrN nano-multilayer film deposited on piston ring

为改善发动机活塞环的摩擦学性能,提高其使用寿命,采用多弧离子镀技术在活塞环表面制备了Cr/CrN纳米多层膜.采用x-射线衍射(XRD)、透射电子显微镜(TEM)、俄歇能谱仪(AES)、纳米硬度仪和CETR摩擦磨损试验机,系统分析了不同调制周期Cr/CrN纳米多层膜的微观结构、成分分布、纳米硬度和抗滑动磨损性能.结果表明:Cr/CrN多层膜由CrN、Cr2N和Cr相组成,在CrN(200)方向上出现择优取向.随调制周期的减小,多层膜的硬度和残余应力增大,当调制周期为80 nm时,多层膜的硬度值最高达到21.5 GPa;当调制周期为120 nm时,H3/E2值达到最高,此时划痕临界载荷值最高.根据摩擦磨损试验结果可知,与电镀Cr和CrN涂层相比,Cr/CrN多层膜具有相对较好的抗滑动磨损性能,其磨损机制主要以磨粒磨损为主,有可能替代原活塞环Cr电镀层.

In order to improve the tribological property of an engine piston ring and increase its service life,a Cr/CrN nano-multilayer film was prepared on the surface of the piston ring with multi-arc ion plating technology.The microstructure,element distribution,nanohardness and slide wear resistance of the Cr/CrN nano-multilayer film with different modulation periods were systematically analyzed with X-ray diffractometer（XRD）,transmission electron microscope（TEM）,auger energy spectrometer（AES）,nanohardness tester as well as CETR friction and wear tester,respectively.The results show that the Cr/CrN multilayer film is composed of CrN,Cr2N and Cr phases,and the preferential orientation of the film appears in CrN（200） direction.With reducing the modulation period,the hardness and residual stress of the film increase.When the modulation period is 80 nm,the hardness of the film reaches the maximum value of 21.5 GPa.When the modulation period is 120 nm,the H3/E2 value attains the maximum level and the scratch critical load value is highest as well.The results of friction and wear experiment show that compared with the electroplated Cr and CrN layers,the Cr/CrN multilayer film has relatively better slide wear resistance,and the corresponding wear mechanism is mainly abrasive wear.The Cr/CrN multilayer film is possibly replace the electroplated Cr layer deposited on the piston ring.