Surface modification of Cr/sub 12/MoV steel by PSII nitrogen implantation

Summary form only given, as follows. The PSII nitrogen implantation for Cr/sub 12/MoV steel modification is performed in the PSII-IM facility. The implantation is carried out at different implantation doses but keeping the other conditions constant. After implantation the samples are analyzed by using a micro-hardness tester, ball-on-disc multifunctional tribometer, X-ray diffraction spectrometer and XPS. The results show that after PSII nitrogen implantation, the surface mechanical properties are improved greatly. The X-ray analysis demonstrates that in the Cr/sub 12/MoV steel, PSII implantation results in hard carbide Fe/sub 7/C/sub 3/ and Cr/sub 7/C/sub 3/ growth because of the high concentration of carbon and fast diffusion speed at elevated temperature implantation. The XPS analysis shows that from the surface to the deep layer, the binding energy of N atoms shift from high energy to low energy. The high energetic ion bombardment, thermal diffusion, fined hard carbide growth and formation of new phrase during nitrogen implantation are the main reasons to improve the surface mechanical properties of Cr/sub 12/ MoV steel at elevated temperature.