VAlN coating is of particular interest for dry cutting applications owing to its low-friction and excellent abrasiveness.Nano-multilayer structure is designed to tailor the properties of VAlN coating.In this work,a se...VAlN coating is of particular interest for dry cutting applications owing to its low-friction and excellent abrasiveness.Nano-multilayer structure is designed to tailor the properties of VAlN coating.In this work,a series of VAlN/Si_(3)N_(4) nano-multilayer coatings with varied Si_(3)N_(4) layer thicknesses were prepared by reactive sputtering method.The microstructure and mechanical properties of the coatings were both investigated.It is revealed that Si_(3)N_(4) with a shallow thickness(~0.4 nm)was crystallized and grown coherently with VAlN,showing a remarkable increase in hardness compared to VAlN monolayer coating.The hardness of coherently VAlN/Si_(3)N_(4) nano-multilayer coatings reached to 48.7 GPa.With further increase of Si_(3)N_(4) layer thickness,the coherent growth of nano-multilayers was terminated,showing amorphous structure formed in nano-multilayers and the hardness was declined.On the other hand,when Si_(3)N_(4) layer thickness was 0.4 nm,the friction coefficient of VAlN/Si_(3)N_(4) nano-multilayer coating was almost equal to that of VAlN monolayer coating,which was attributed to the crystallization of Si_(3)N_(4) and the produced coherent interfaces between VAlN and Si_(3)N_(4) for the hardening effect of nano-multilayer coatings.Upon further increase of Si_(3)N_(4) layer thickness,pronounced improvement of friction coefficient in VAlN/Si_(3)N_(4) nano-multilayer coating was observed.展开更多
A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphol...A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution.展开更多
基金Project(51201187)supported by the National Natural Science Foundation of China。
文摘VAlN coating is of particular interest for dry cutting applications owing to its low-friction and excellent abrasiveness.Nano-multilayer structure is designed to tailor the properties of VAlN coating.In this work,a series of VAlN/Si_(3)N_(4) nano-multilayer coatings with varied Si_(3)N_(4) layer thicknesses were prepared by reactive sputtering method.The microstructure and mechanical properties of the coatings were both investigated.It is revealed that Si_(3)N_(4) with a shallow thickness(~0.4 nm)was crystallized and grown coherently with VAlN,showing a remarkable increase in hardness compared to VAlN monolayer coating.The hardness of coherently VAlN/Si_(3)N_(4) nano-multilayer coatings reached to 48.7 GPa.With further increase of Si_(3)N_(4) layer thickness,the coherent growth of nano-multilayers was terminated,showing amorphous structure formed in nano-multilayers and the hardness was declined.On the other hand,when Si_(3)N_(4) layer thickness was 0.4 nm,the friction coefficient of VAlN/Si_(3)N_(4) nano-multilayer coating was almost equal to that of VAlN monolayer coating,which was attributed to the crystallization of Si_(3)N_(4) and the produced coherent interfaces between VAlN and Si_(3)N_(4) for the hardening effect of nano-multilayer coatings.Upon further increase of Si_(3)N_(4) layer thickness,pronounced improvement of friction coefficient in VAlN/Si_(3)N_(4) nano-multilayer coating was observed.
基金Project(51001007) supported by the National Natural Science Foundation of ChinaProject(2011ZE51057) supported by the Aero Science Foundation of China
文摘A novel kind of waterborne epoxy coating pigmented by nano-sized aluminium powders on high strength steel was formulated. Several coatings with different pigment volume content (PVC) were prepared. The coating morphology was observed using scanning electron microscopy (SEM), and the electrochemical properties were investigated by electrochemical impedance spectroscopy (EIS). Immersion test and neutral salt spray test were also conducted to investigate the corrosion resistance of the coating. It is demonstrated that the critical pigment volume content (CPVC) value is between 30% and 40%. The coating with PVC of 30% exhibits good corrosion resistance in 3.5% (mass fraction) NaCl solution.
