Hard coatings have been widely applied to enhance tribological performance of mechanical components.However,it was predicted that thin hard coatings may have a weakening effect which could reduce the coating/substrate...Hard coatings have been widely applied to enhance tribological performance of mechanical components.However,it was predicted that thin hard coatings may have a weakening effect which could reduce the coating/substrate system’s resistance to plastic yielding compared with the uncoated substrate material.In this paper,analytical simulation is utilized to investigate the origin of weakening effect.The functions of material mechanical properties and coating thickness on the weakening effect are theoretically investigated.Partial-unloading spherical nanoindentation tests are performed on tungsten coated single crystalline silicon and copper to acquire the stress-strain curves and compared with the uncoated cases.The experimental results are in consistence with the analytical solutions,demonstrating the presence of weakening effect.展开更多
Triboelectrification between a liquid and a solid is a common phenomenon in our daily life and industry.Triboelectric charges generated at liquid/solid interfaces have effects on energy harvesting,triboelectrification...Triboelectrification between a liquid and a solid is a common phenomenon in our daily life and industry.Triboelectric charges generated at liquid/solid interfaces have effects on energy harvesting,triboelectrification-based sensing,interfacial corrosion,wear,lubrication,etc.Knowing the amount of triboelectric charge transfer is very useful for studying the mechanism and controlling these phenomena,in which an accurate method is absolutely necessary to measure the triboelectric charge generated at the solid–liquid interface.Herein,we established a method for measuring the charge transfer between different solids and liquids.An equipment based on the Faraday cup measurement was developed,and the leakage ratio(r_(l))was quantified through simulation based on an electrostatic field model.Typical experiments were conducted to validate the reliability of the method.This work provides an effective method for charge measurement in triboelectrification research.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.51705533)the National Science and Technology Major Project of China(Grant No.2017-VII-0013-0110)+1 种基金the Fundamental Research Funds for the Central Universities,China(Grant No.2020YQJD17)the Tribology Science Fund of State Key Laboratory of Tribology(Grant No.SKLTKF18B15).
文摘Hard coatings have been widely applied to enhance tribological performance of mechanical components.However,it was predicted that thin hard coatings may have a weakening effect which could reduce the coating/substrate system’s resistance to plastic yielding compared with the uncoated substrate material.In this paper,analytical simulation is utilized to investigate the origin of weakening effect.The functions of material mechanical properties and coating thickness on the weakening effect are theoretically investigated.Partial-unloading spherical nanoindentation tests are performed on tungsten coated single crystalline silicon and copper to acquire the stress-strain curves and compared with the uncoated cases.The experimental results are in consistence with the analytical solutions,demonstrating the presence of weakening effect.
文摘Triboelectrification between a liquid and a solid is a common phenomenon in our daily life and industry.Triboelectric charges generated at liquid/solid interfaces have effects on energy harvesting,triboelectrification-based sensing,interfacial corrosion,wear,lubrication,etc.Knowing the amount of triboelectric charge transfer is very useful for studying the mechanism and controlling these phenomena,in which an accurate method is absolutely necessary to measure the triboelectric charge generated at the solid–liquid interface.Herein,we established a method for measuring the charge transfer between different solids and liquids.An equipment based on the Faraday cup measurement was developed,and the leakage ratio(r_(l))was quantified through simulation based on an electrostatic field model.Typical experiments were conducted to validate the reliability of the method.This work provides an effective method for charge measurement in triboelectrification research.
