Interfaces in nanostructured thin films and their influence on hardness
2005; De Gruyter; Volume: 96; Issue: 5 Linguagem: Inglês
10.3139/146.018132
ISSN0044-3093
AutoresP.H. Mayrhofer, Helmut Clemens, Christian Mitterer,
Tópico(s)Advanced materials and composites
ResumoNanocrystalline structures have attracted increasing interest in modem development of hard films for wear-resistant applications. In plasma-assisted vapor-deposited thin films, nanostructures can be generated during growth or post-annealing treatment. In this review, we demonstrate, using the four model-films overstoichiometric TiB 2 , TiN-TiB 2 , Ti(B)N, and Ti 0 . 3 3 Al 0 . 6 7 N, how interfaces influence the mechanical properties of ceramic thin films. For overstoichiometric TiB 2 films and TiN-TiB 2 , a two-dimensional and three-dimensional nanostructure, respectively, is generated during growth by segregation-driven processes. Growth of less B containing Ti(B)N films and Ti 0 . 3 3 Al 0 . 6 7 N results in the formation of a supersaturated TiN phase with NaCI structure, where either the non-metallic part or the metallic part is substituted by B or Al, respectively. For these films, the nanostructure forms during post-annealing, due to the decomposition of the supersaturated phases into their stable constituents. As the hardness of a material is determined by resistance to bond distortion and, dislocation formation and motion, which themselves depend on the amount of interfaces and their constitution, there is a direct relation between hardness and nanostructure.
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