A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was performed.Ni or Cu atoms were shown to adopt the corresponding position ...A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was performed.Ni or Cu atoms were shown to adopt the corresponding position to the bcc structure of the Fe(100) substrate.Other calculations showed that the interfaces of Ni(5 atomic layers)/Fe(100)(5 layers) or Cu(5 atomic layers)/Fe(100)(5 layers) had square lattices.The orientation relationship of Ni/Fe(100) interface corresponds to fcc-Ni(100)//bcc-Fe(100),Ni[011]//Fe[010],and Ni[011]//Fe[001].Similar results were obtained for Cu/Fe(100) interfaces.This structure was supported by TEM analysis of plated Ni layer on Fe(100) surfaces.The adhesion strength of the Ni/Fe(100) interface evaluated by first principles calculation was higher than that of the Cu/Fe(100) interface.The experimental results of Hull cell iron plated with Ni or Cu supported the results of the calculation.These results indicate that the first principles calculation,which deals with the ideal interface at the atomic scale,has the potential to evaluate the adhesion strength of metallic material interfaces.展开更多
The developments in power transmission via HVDC networks are fast,especially in Western Europe and China.The challenges that we are confronted with are huge and considerable research and development efforts are requir...The developments in power transmission via HVDC networks are fast,especially in Western Europe and China.The challenges that we are confronted with are huge and considerable research and development efforts are required.Special attention is needed for high voltage direct current(HVDC)and ultra-high voltage dc(UHVDC)underground cables.For the highest voltage levels,we are still dependent upon classic technology based on mass-impregnated paper used in line commutated converter(LCC)systems.Gradually,more and more polymeric type cables are appearing on the market,as yet mainly for voltage source converter(VSC)systems.For financial,environmental and technical reasons the full focus is now on polymeric type cables,for use in LCC or VSC systems.In this paper,a closer look is taken at the interfaces in polymeric cable systems,i.e.in the cables and in the cable accessories.In the design process,we are challenged by the presence of interfaces from an electrical and thermal point of view.In the field of electrical insulation,the interfaces between different materials are generally considered the weakest parts of the equipment and under DC stresses the situation becomes even more complex due to the charge dynamics at the interface.Indeed,the design of(U)HVDC accessories has become a challenge if not a problem.This paper focuses on some of the important electrical and thermal aspects of interfaces in HVDC polymeric cables.It is discussed where we lack knowledge and where we may benefit from other scientific展开更多
文摘A study the with first principles calculation of the interfaces of the Ni layer or Cu layer on the Fe(100) surface formed with metal plating was performed.Ni or Cu atoms were shown to adopt the corresponding position to the bcc structure of the Fe(100) substrate.Other calculations showed that the interfaces of Ni(5 atomic layers)/Fe(100)(5 layers) or Cu(5 atomic layers)/Fe(100)(5 layers) had square lattices.The orientation relationship of Ni/Fe(100) interface corresponds to fcc-Ni(100)//bcc-Fe(100),Ni[011]//Fe[010],and Ni[011]//Fe[001].Similar results were obtained for Cu/Fe(100) interfaces.This structure was supported by TEM analysis of plated Ni layer on Fe(100) surfaces.The adhesion strength of the Ni/Fe(100) interface evaluated by first principles calculation was higher than that of the Cu/Fe(100) interface.The experimental results of Hull cell iron plated with Ni or Cu supported the results of the calculation.These results indicate that the first principles calculation,which deals with the ideal interface at the atomic scale,has the potential to evaluate the adhesion strength of metallic material interfaces.
文摘The developments in power transmission via HVDC networks are fast,especially in Western Europe and China.The challenges that we are confronted with are huge and considerable research and development efforts are required.Special attention is needed for high voltage direct current(HVDC)and ultra-high voltage dc(UHVDC)underground cables.For the highest voltage levels,we are still dependent upon classic technology based on mass-impregnated paper used in line commutated converter(LCC)systems.Gradually,more and more polymeric type cables are appearing on the market,as yet mainly for voltage source converter(VSC)systems.For financial,environmental and technical reasons the full focus is now on polymeric type cables,for use in LCC or VSC systems.In this paper,a closer look is taken at the interfaces in polymeric cable systems,i.e.in the cables and in the cable accessories.In the design process,we are challenged by the presence of interfaces from an electrical and thermal point of view.In the field of electrical insulation,the interfaces between different materials are generally considered the weakest parts of the equipment and under DC stresses the situation becomes even more complex due to the charge dynamics at the interface.Indeed,the design of(U)HVDC accessories has become a challenge if not a problem.This paper focuses on some of the important electrical and thermal aspects of interfaces in HVDC polymeric cables.It is discussed where we lack knowledge and where we may benefit from other scientific
