“…Also, the hardness values of a variety of superhard nanocomposites measured by the load-depth sensing technique at sufficiently large loads of 50 to 200 mN (in the case of 15-20-µm-thick coatings even up to 1000 mN) agree fairly well with the Vickers hardness calculated from the projected area of the plastic deformation within the broad range of hardness between 20 and 100 GPa [9]. These nanocomposites were deposited by plasma CVD and, therefore, have a low compressive stress of ≤1 GPa.…”
Section: Introductionsupporting
confidence: 62%
“…Thus, an appropriate selection of binary or ternary refractory hard materials allows one to prepare superhard nanocomposites whose nanostructure and the resultant hardness remain stable up to high temperatures of 1100 °C. For further details, we refer to [9][10][11].…”
Section: Generic Design Concept and Thermal Stability Of Superhard Namentioning
confidence: 99%
“…All the superhard nanocomposites are deposited by means of plasma induced processing, such as plasma-induced CVD [1,[9][10][11][17][18] and PVD including magnetron sputtering [6,12,13] and vacuum arc evaporation [14]. Alternatively, combined plasma PVD and CVD are used in which the metals (Ti, Al, ...) are evaporated either by means of vacuum arc [14,15] or by sputtering [16] and the nonmetals are introduced as gaseous reactants (e.g., SiH 4 , BCl 3 , B 3 N 3 H 6 ).…”
A variety of superhard coatings with Vickers plastic hardness exceeding 40 GPa have been reported by several research groups during the last five years (for recent reviews see refs [1,2]). However, one has to distinguish between superhard nanocomposites, such as nc-TiN/a-Si 3 N 4 , nc-TiN/a-Si 3 N 4 /a-and nc-TiSi 2 , nc-(Ti 1-x Al x )N/a-Si 3 N 4 , nc-TiN/TiB 2 , ncTiN/BN, etc. where the high hardness originates from the nanostrucutre and, therefore, remains stable upon annealing to high temperatures [1], and coatings, such as CrN/Ni, ZrN/Ni, and others [2] in which the measured high hardness is due to a high compressive stress that is induced in the coatings due to energetic ion bombardment during their deposition (e.g., by magnetron sputtering). We also summarize the recent progress in the industrial applications of the superhard nanocomposite coatings on machining tools.
“…Also, the hardness values of a variety of superhard nanocomposites measured by the load-depth sensing technique at sufficiently large loads of 50 to 200 mN (in the case of 15-20-µm-thick coatings even up to 1000 mN) agree fairly well with the Vickers hardness calculated from the projected area of the plastic deformation within the broad range of hardness between 20 and 100 GPa [9]. These nanocomposites were deposited by plasma CVD and, therefore, have a low compressive stress of ≤1 GPa.…”
Section: Introductionsupporting
confidence: 62%
“…Thus, an appropriate selection of binary or ternary refractory hard materials allows one to prepare superhard nanocomposites whose nanostructure and the resultant hardness remain stable up to high temperatures of 1100 °C. For further details, we refer to [9][10][11].…”
Section: Generic Design Concept and Thermal Stability Of Superhard Namentioning
confidence: 99%
“…All the superhard nanocomposites are deposited by means of plasma induced processing, such as plasma-induced CVD [1,[9][10][11][17][18] and PVD including magnetron sputtering [6,12,13] and vacuum arc evaporation [14]. Alternatively, combined plasma PVD and CVD are used in which the metals (Ti, Al, ...) are evaporated either by means of vacuum arc [14,15] or by sputtering [16] and the nonmetals are introduced as gaseous reactants (e.g., SiH 4 , BCl 3 , B 3 N 3 H 6 ).…”
A variety of superhard coatings with Vickers plastic hardness exceeding 40 GPa have been reported by several research groups during the last five years (for recent reviews see refs [1,2]). However, one has to distinguish between superhard nanocomposites, such as nc-TiN/a-Si 3 N 4 , nc-TiN/a-Si 3 N 4 /a-and nc-TiSi 2 , nc-(Ti 1-x Al x )N/a-Si 3 N 4 , nc-TiN/TiB 2 , ncTiN/BN, etc. where the high hardness originates from the nanostrucutre and, therefore, remains stable upon annealing to high temperatures [1], and coatings, such as CrN/Ni, ZrN/Ni, and others [2] in which the measured high hardness is due to a high compressive stress that is induced in the coatings due to energetic ion bombardment during their deposition (e.g., by magnetron sputtering). We also summarize the recent progress in the industrial applications of the superhard nanocomposite coatings on machining tools.
“…From this aspect, Veprek et al designed single layer nanocomposite coatings with hardness !40 GPa using plasma CVD process either in a high frequency or direct current discharge [453][454][455][456][457][458][459][460][461][462]. In the process, a hard transition metal nitride and a covalent nitride (e.g.…”
Section: Superhard and Super-tough Nanocrystalline Coatingsmentioning
In recent years, near-nano (submicron) and nanostructured materials have attracted increasingly more attention from the materials community. Nanocrystalline materials are characterized by a microstructural length or grain size of up to about 100 nm. Materials having grain size of $0.1 to 0.3 mm are classified as submicron materials. Nanocrystalline materials exhibit various shapes or forms, and possess unique chemical, physical or mechanical properties. When the grain size is below a critical value ($10-20 nm), more than 50 vol.% of atoms is associated with grain boundaries or interfacial boundaries. In this respect, dislocation pile-ups cannot form, and the Hall-Petch relationship for conventional coarse-grained materials is no longer valid. Therefore, grain boundaries play a major role in the deformation of nanocrystalline materials. Nanocrystalline materials exhibit creep and super plasticity at lower temperatures than conventional micro-grained counterparts. Similarly, plastic deformation of nanocrystalline coatings is considered to be associated with grain boundary sliding assisted by grain boundary diffusion or rotation. In this review paper, current developments in fabrication, microstructure, physical and mechanical properties of nanocrystalline materials and coatings will be addressed. Particular attention is paid to the properties of transition metal nitride nanocrystalline films formed by ion beam assisted deposition process. #
“…1 Hard nanocomposites of several material systems have been studied, e.g., Ti-Si-N, 1,2 Ti-Si-C-N, 3,4 Zr-Si-N, 5 and Ti-B-N. 6,7 Such nanocomposites also retain their hardness at high temperatures since the grain growth is hindered by the amorphous matrix. 8 Also two-phase nanocrystalline materials in the form of multilayers exhibit an increased hardness compared to their constituents due to the difference in elastic properties between the layers that hinder dislocation motion, 9 most clearly seen in nanoscale multilayers. 10,11 The decomposition of metastable single-phase films can also act to improve the hardness at elevated temperature as a two-phase structure is formed.…”
Nanocomposite Zr 0.52 Al 0.48 N 1.11 thin films consisting of crystalline grains surrounded by an amorphous matrix were deposited using cathodic arc evaporation. The structure evolution after annealing of the films was studied using high-energy x-ray scattering and transmission electron microscopy. The mechanical properties were characterized by nanoindentation on as-deposited and annealed films. After annealing in temperatures of 1050-1400°C, nucleation and grain growth of cubic ZrN takes place in the film. This increases the hardness, which reaches a maximum, while parts of the film remain amorphous. Grain growth of the hexagonal AlN phase occurs above 1300°C.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.