The a-C and a-C：H films are deposited on silicon surfaces modified with and without nickel nanoparticles by using mid-frequency magnetron sputtering. The microstructures and morphologies of the films are analyzed by ...The a-C and a-C：H films are deposited on silicon surfaces modified with and without nickel nanoparticles by using mid-frequency magnetron sputtering. The microstructures and morphologies of the films are analyzed by Raman spec- troscopy and atomic force microscopy. Field emission behaviors of the deposited films with and without nickel nanopar- ticles modification are comparatively investigated. It is found that the hydrogen-free carbon film exhibits a high field emission current density and low turn-on electric field compared with the hydrogenated carbon film. Nickel modifying could increase the current density, whereas it has no significant effect on the turn-on electric field. The mechanism of field electron emission of a sample is discussed from the surface morphologies of the films and nickel nanoparticle roles in the interface between film and substrate.展开更多
Improvement of mechanical and tribological behaviors of zinc-based die cast alloy is necessary for bearing applications,and chemical modification is found to be a good choice.Chemical modification of Zn-27wt.%Al alloy...Improvement of mechanical and tribological behaviors of zinc-based die cast alloy is necessary for bearing applications,and chemical modification is found to be a good choice.Chemical modification of Zn-27wt.%Al alloy was carried out with 1%,2%and 3%nickel through casting route,and its effect on microstructure,hardness,and dry sliding wear behavior was investigated.Significant refinement of dendritic microstructure is observed along with a transformation from rosette to near rounded morphology with the increase in nickel content of base alloy.With 1%nickel modification,an aluminum-rich Al_(3)Ni intermetallic compound of string type forms in inter dendritic region,while with 2%and 3%nickel modifications,a nickel-rich AlNi3 intermetallic compound of lath/plate type is formed within the intra dendritic region.Hardness of the base alloy is improved through grain boundary strengthening at a lower concentration of nickel,and particulate strengthening and spinodal decomposition are the reason for increase in hardness of the alloy with a higher content of nickel.Coefficient of friction and wear rate of base alloy is decreased with increasing nickel amount.Worn surface is characterized by delamination,smearing and grooving.The wear mechanism is transferred from adhesion to abrasive via oxide film formation with an increase in amount of nickel.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51105186)
文摘The a-C and a-C：H films are deposited on silicon surfaces modified with and without nickel nanoparticles by using mid-frequency magnetron sputtering. The microstructures and morphologies of the films are analyzed by Raman spec- troscopy and atomic force microscopy. Field emission behaviors of the deposited films with and without nickel nanopar- ticles modification are comparatively investigated. It is found that the hydrogen-free carbon film exhibits a high field emission current density and low turn-on electric field compared with the hydrogenated carbon film. Nickel modifying could increase the current density, whereas it has no significant effect on the turn-on electric field. The mechanism of field electron emission of a sample is discussed from the surface morphologies of the films and nickel nanoparticle roles in the interface between film and substrate.
基金Science and Engineering Research Board(SERB),Government of India,New Delhi,India for funding under an R&D project to procure a high-temperature furnace.
文摘Improvement of mechanical and tribological behaviors of zinc-based die cast alloy is necessary for bearing applications,and chemical modification is found to be a good choice.Chemical modification of Zn-27wt.%Al alloy was carried out with 1%,2%and 3%nickel through casting route,and its effect on microstructure,hardness,and dry sliding wear behavior was investigated.Significant refinement of dendritic microstructure is observed along with a transformation from rosette to near rounded morphology with the increase in nickel content of base alloy.With 1%nickel modification,an aluminum-rich Al_(3)Ni intermetallic compound of string type forms in inter dendritic region,while with 2%and 3%nickel modifications,a nickel-rich AlNi3 intermetallic compound of lath/plate type is formed within the intra dendritic region.Hardness of the base alloy is improved through grain boundary strengthening at a lower concentration of nickel,and particulate strengthening and spinodal decomposition are the reason for increase in hardness of the alloy with a higher content of nickel.Coefficient of friction and wear rate of base alloy is decreased with increasing nickel amount.Worn surface is characterized by delamination,smearing and grooving.The wear mechanism is transferred from adhesion to abrasive via oxide film formation with an increase in amount of nickel.
