Polyetheretherketone (PEEK) based composite materials become of great interest to applications as bearing and slider materials due to their excellent tribological performance. In present work, graphite and MoS2 (7%, w...Polyetheretherketone (PEEK) based composite materials become of great interest to applications as bearing and slider materials due to their excellent tribological performance. In present work, graphite and MoS2 (7%, wt) filled PEEK coatings were prepared using serigraph technique. Employing a uniform design experiment, the friction behavior of the composite coatings was systematically investigated under dry sliding conditions on a ball-on-disc arrangement. The evolution mechanism of coating friction coefficient was discussed. Correlation of coatings friction coefficient with sliding velocity and applied load was accomplished using stepwise regression method. The results indicate that friction coefficients of PEEK + MoS2 and PEEK + graphite coating decrease while increasing applied load. Moreover, friction coefficient of PEEK + MoS2 coating increases with increasing sliding velocity.展开更多
High purity Mg was successfully coated on polyetheretherketone(PEEK)by vapor deposition method in order to improve the bioactivity including antibacterial property of PEEK implant.The morphology and elemental composit...High purity Mg was successfully coated on polyetheretherketone(PEEK)by vapor deposition method in order to improve the bioactivity including antibacterial property of PEEK implant.The morphology and elemental composition of the coating were characterized by scanning electron microscopy(SEM)and energy-dispersive spectroscopy(EDS),showing that the coating was mainly composed of Mg at deposition temperature of 175C,185C,200C and 230C.The higher the substrate temperature was,the larger the Mg particle size was.The coating degraded and gradually peeled off from the surface of PEEK after up to 21 days'immersion.It was found that the degradation of Mg coating could strongly kill Staphylococcus aureus with antibacterial rate reaching to 99%.Mg can be expected to be coated on those bio-inert biomaterials to offer specific bioactivities.展开更多
In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which ...In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as well.Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and stops.Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the paper.The tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/Babbitt.The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction regime.Analysis of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific conditions.More specifically,the DLC/steel bearing was demonstrating superior performance,i.e.lower friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.展开更多
文摘Polyetheretherketone (PEEK) based composite materials become of great interest to applications as bearing and slider materials due to their excellent tribological performance. In present work, graphite and MoS2 (7%, wt) filled PEEK coatings were prepared using serigraph technique. Employing a uniform design experiment, the friction behavior of the composite coatings was systematically investigated under dry sliding conditions on a ball-on-disc arrangement. The evolution mechanism of coating friction coefficient was discussed. Correlation of coatings friction coefficient with sliding velocity and applied load was accomplished using stepwise regression method. The results indicate that friction coefficients of PEEK + MoS2 and PEEK + graphite coating decrease while increasing applied load. Moreover, friction coefficient of PEEK + MoS2 coating increases with increasing sliding velocity.
基金The authors gratefully acknowledge the financial support from Key Program of China on Biomedical Materials Research and Tissue and Organ Replacement(2016YFC1101804)National Natural Science Foundation of China(51631009,81500897,81400528)。
文摘High purity Mg was successfully coated on polyetheretherketone(PEEK)by vapor deposition method in order to improve the bioactivity including antibacterial property of PEEK implant.The morphology and elemental composition of the coating were characterized by scanning electron microscopy(SEM)and energy-dispersive spectroscopy(EDS),showing that the coating was mainly composed of Mg at deposition temperature of 175C,185C,200C and 230C.The higher the substrate temperature was,the larger the Mg particle size was.The coating degraded and gradually peeled off from the surface of PEEK after up to 21 days'immersion.It was found that the degradation of Mg coating could strongly kill Staphylococcus aureus with antibacterial rate reaching to 99%.Mg can be expected to be coated on those bio-inert biomaterials to offer specific bioactivities.
文摘In hydrodynamic bearings traditional bearing alloys:Babbitts and bronzes are most frequently utilized.Polymer sliding layers are sometimes applied as a valuable alternative.Hard diamond-like carbon(DLC)coatings,which are also considered for certain applications may show some advantages,as well.Although material selection is of secondary importance in a full film lubrication regime it becomes important in mixed friction conditions,which is crucial for bearings with frequent starts and stops.Experimental research aimed at studying the performance of fluid film bearings in the specific operating regime,including the transition to mixed friction,is described in the paper.The tests were carried out on four tilting pad bearings of different material compositions:Steel/bronze,DLC/steel,steel/polyether ether ketone(PEEK),and steel/Babbitt.The tests comprised stopping under load and reproduction of the Stribeck curve by decreasing rotational speed to very low values,and observing the changes of friction force during the transition to mixed friction regime.Analysis of the transition conditions and other results showed clear differences between the tested bearings,illustrating the feasibility of less popular material compositions for bearings operating in specific conditions.More specifically,the DLC/steel bearing was demonstrating superior performance,i.e.lower friction,transition to mixed friction occurring at higher load,and more stable performance at start-stop regime over the other tested bearings.
