The surface composition of low alloy steel after N_2^+ implantation was studied with X-ray photo-electron spectroscopy (XPS). The effect of the implantation on the mechanical hardness was evaluated by ultra-micro hard...The surface composition of low alloy steel after N_2^+ implantation was studied with X-ray photo-electron spectroscopy (XPS). The effect of the implantation on the mechanical hardness was evaluated by ultra-micro hardness indentation. Chemical characterisation of the surface indi- cated that a thin layer rich in N, C and Si was formed. It is shown that Fe played little role in the chemical composition and the structure of the modified surface. The mechanical hardness of N_2^+ implanted surface was 35-50 GPa compared with a value of 10 GPa for the untreated sample. It is thought that the high hardness observed on the surface and in the sub-surface was as a result of chemical modification to form a film of Si doped carbon nitride. There is strong evidence from the XPS and the nanoindentation studies that the bonding structure of the C-N in the near surface is essentially sp^3 types expected in crystalline C_3N_4. The value of nitrogen ion implantation as process for improving the wear resistance of low alloy steels is emphasized.展开更多
文摘The surface composition of low alloy steel after N_2^+ implantation was studied with X-ray photo-electron spectroscopy (XPS). The effect of the implantation on the mechanical hardness was evaluated by ultra-micro hardness indentation. Chemical characterisation of the surface indi- cated that a thin layer rich in N, C and Si was formed. It is shown that Fe played little role in the chemical composition and the structure of the modified surface. The mechanical hardness of N_2^+ implanted surface was 35-50 GPa compared with a value of 10 GPa for the untreated sample. It is thought that the high hardness observed on the surface and in the sub-surface was as a result of chemical modification to form a film of Si doped carbon nitride. There is strong evidence from the XPS and the nanoindentation studies that the bonding structure of the C-N in the near surface is essentially sp^3 types expected in crystalline C_3N_4. The value of nitrogen ion implantation as process for improving the wear resistance of low alloy steels is emphasized.