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Surface Engineering of Metals - Principles, Equipment and Technologies Part 9

Tham khảo tài liệu 'surface engineering of metals - principles, equipment and technologies part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Fig. 4.3 Depth of implantation a schematic portraying the range of ion implantation b dependence of ion implantation range Rp and standard deviation ARp on energy of implantation of nitrogen ions into iron c Gaussian implantation profile for nitrogen ion implantation in iron d distribution of concentration of ions implanted in an amorphous body and distribution of defects caused by them e defect formation in substrate C by an incident ion several thousand atom translocations in the lattice and the formation of sputter cascades A and B several hundred vacancies and several hundred interstitial atoms 1 - implantation profile 2 - defects profile 3 - implanted atoms diffusion 4 - sputtered atoms. effect is insignificant and then there may occur an additional maximum of concentration of implanted ions in the vicinity of R . The curve which determines the distribution of implanted ions at different depths in the host material is known as the implantation profile. Maximum concentration of implanted ions especially those of light elements is not at the surface of the host material but at a distance of some 1999 by CRC Press LLC tenths of a micrometer from it due to backscatter and the non-elastic character of interaction of the ions with electrons of the host material. Implanted ions colliding with atoms of the host material causes their displacement which in turn causes the formation of radiation defects. Since the energy of the ion several dozen keV is several thousand times greater than the energy of atom bonds in the lattice in metals it is approximately 25 eV one ion is capable of knocking even several thousand atoms out of their nodular positions. In this way the implanted ion generates along its path a strongly defected zone known as a cascade of several to several tens nanometers which propagates laterally to the direction of the ion movement due to the secondary interaction of atoms knocked out from their positions. The number of defects exceeds the number of .