The improvement in the properties of tools and components after ion implantation is the result of specific structural-phase states developed both in the implanted zone (IZ) and beyond into the implantation-affected zone (IAZ). The formation of defect structures beyond the implanted zone is called the long-range effect and occurs both in metals having high plasticity and low yield strength and in high-strength materials. In the present work, the microstructure of TiN coatings deposited by PVD and CVD methods is studied by transmission electron microscopy. Before dual implantation with Ni and Ti ions the PVD coating has a highly non-equilibrium submicron crystal structure with a high level of local residual stress, whereas the CVD TiN coating has a microcrystalline structure with low internal residual stress. Implantation into PVD TiN causes a relaxation of the local stress in the IZ and beyond. In contrast, in CVD TiN ion implantation leads to the development of subgrains, both within the IZ and immediately below it, in the IAZ of the coating. No additional phases are formed in either case. A possible mechanism for explaining the formation of the defect structure beyond the IZ is introduced. This is based on the emission of a dislocation flux from stress maxima developed at the IZ-IAZ interface in the form of mezo-bands.
|Журнал||Surface and Coatings Technology|
|Состояние||Опубликовано - 10 окт 1998|
ASJC Scopus subject areas
- Surfaces, Coatings and Films
- Condensed Matter Physics
- Surfaces and Interfaces