Wear behaviors of a peak-aged Cu-15Ni-8Sn alloy fabricated by powder metallurgy were investigated.The results indicated that the friction coefficients and the wear rates of Cu-15Ni-8Sn alloy within a normal load range...Wear behaviors of a peak-aged Cu-15Ni-8Sn alloy fabricated by powder metallurgy were investigated.The results indicated that the friction coefficients and the wear rates of Cu-15Ni-8Sn alloy within a normal load range of 50−700 N and a sliding speed range of 0.05−2.58 m/s were less than 0.14 and 2.8×10−6 mm3/mm,respectively.Stribeck-like curve and wear map were developed to describe the oil-lubrication mechanism and wear behavior.The equation of the dividing line between zones of safe and unsafe wear life was determined.Lubricating oil was squeezed into micro-cracks under severe wear conditions.In addition,the lubricating oil reacted with Cu-15Ni-8Sn alloy to generate the corresponding sulfides,which hindered the repair of micro-cracks,promoted cracks growth,and led to delamination.This work has established guidelines for the application of the Cu-15Ni-8Sn alloy under oil-lubricated conditions through developing wear map.展开更多
Tribological behavior of Cu-15Ni-8Sn(mass fraction, %) alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly...Tribological behavior of Cu-15Ni-8Sn(mass fraction, %) alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly from 1.7×10^(-7) to 9.8× 10^(-7) mm^3/mm under the load lower than 300 N, and then increased dramatically to the climax of 216×10^(-7) mm^3/mm under the load over 300 N, which indicated the transition of wear mechanism with the increase of applied load. The wear mechanism mainly was plastic deformation and abrasive wear under the load less than 300 N. As the applied load was more than 300 N, the wear mechanism of Cu-15Ni-8Sn alloy primarily was delamination wear. Besides, the transition can also be confirmed from the different morphologies of worn surface, subsurface and wear debris. It is distinctly indicated that the appearance of flaky debris at the applied load over 300 N may be a critical point for the change of wear mechanism.展开更多
Oleic acid surface-modified Cu nanoparticles with an average size of 20 nm were prepared by liquid phase reducing reaction. The tribological performance and mechanism of nanocopper as additive were studied by means of...Oleic acid surface-modified Cu nanoparticles with an average size of 20 nm were prepared by liquid phase reducing reaction. The tribological performance and mechanism of nanocopper as additive were studied by means of tribotester, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and nanoindentation instrument. The results indicate that the modified nanocopper additive can significantly improve the wear resistance and reduce friction coefficient of base oil. A copper protective film is formed and contributes to the excellent tribological properties of nanocopper additive. On the basis of the film forming mechanism, a new in-situ repair method was designed and used to repair wear-out-failure injection pump plunger and barrel. Furthermore, the current research progress of nanoparticles as green energy-saving lubricating oil additives were presented.展开更多
基金Projects(2017YFB0306105,2018YFE0306100)supported by the National Key Research and Development Program of China
文摘Wear behaviors of a peak-aged Cu-15Ni-8Sn alloy fabricated by powder metallurgy were investigated.The results indicated that the friction coefficients and the wear rates of Cu-15Ni-8Sn alloy within a normal load range of 50−700 N and a sliding speed range of 0.05−2.58 m/s were less than 0.14 and 2.8×10−6 mm3/mm,respectively.Stribeck-like curve and wear map were developed to describe the oil-lubrication mechanism and wear behavior.The equation of the dividing line between zones of safe and unsafe wear life was determined.Lubricating oil was squeezed into micro-cracks under severe wear conditions.In addition,the lubricating oil reacted with Cu-15Ni-8Sn alloy to generate the corresponding sulfides,which hindered the repair of micro-cracks,promoted cracks growth,and led to delamination.This work has established guidelines for the application of the Cu-15Ni-8Sn alloy under oil-lubricated conditions through developing wear map.
基金Project(2016YFB0301402)supported by the National Key Research and Development Program of ChinaProject(CSU20151024)supported by the Innovation-driven Plan in Central South University,China
文摘Tribological behavior of Cu-15Ni-8Sn(mass fraction, %) alloy against GCr15 ring under various loads was investigated on a ring-on-block tester in oil lubrication. The results showed that the wear rate increased slowly from 1.7×10^(-7) to 9.8× 10^(-7) mm^3/mm under the load lower than 300 N, and then increased dramatically to the climax of 216×10^(-7) mm^3/mm under the load over 300 N, which indicated the transition of wear mechanism with the increase of applied load. The wear mechanism mainly was plastic deformation and abrasive wear under the load less than 300 N. As the applied load was more than 300 N, the wear mechanism of Cu-15Ni-8Sn alloy primarily was delamination wear. Besides, the transition can also be confirmed from the different morphologies of worn surface, subsurface and wear debris. It is distinctly indicated that the appearance of flaky debris at the applied load over 300 N may be a critical point for the change of wear mechanism.
文摘Oleic acid surface-modified Cu nanoparticles with an average size of 20 nm were prepared by liquid phase reducing reaction. The tribological performance and mechanism of nanocopper as additive were studied by means of tribotester, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and nanoindentation instrument. The results indicate that the modified nanocopper additive can significantly improve the wear resistance and reduce friction coefficient of base oil. A copper protective film is formed and contributes to the excellent tribological properties of nanocopper additive. On the basis of the film forming mechanism, a new in-situ repair method was designed and used to repair wear-out-failure injection pump plunger and barrel. Furthermore, the current research progress of nanoparticles as green energy-saving lubricating oil additives were presented.
