The role of percolation threshold for the control of the hardness and thermal stability of super- and ultrahard nanocomposites

Niederhofer, A.; Bolom, T.; Nesládek, Pavel; Moto, Keba; Eggs, C.; Patil, D. S.; Vepřek, S.

doi:10.1016/s0257-8972(01)01469-4

Cited by 132 publications

(48 citation statements)

References 14 publications

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“…coatings [4,26,27]. Scratch tests were conducted on the coatings and the results are shown in Table 1.…”

Section: Lubrication -Tribology Lubricants and Additivesmentioning

confidence: 99%

Surface Morphology and Tribological Properties of Nanoscale (Ti, Al, Si, C)N Multilayer Coatings Deposited by Reactive Magnetron Sputtering

Wang¹,

Miyake²

2018

Lubrication - Tribology, Lubricants and Additives

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The current topics related to the morphology and tribology of TiAlN monolayer, TiAlN/ SiNx, TiAlN/CNx and TiAlN/CNxAECNx nanoscale multilayer coatings and refer to our recent results on the evaluation of surface morphology, and nanoscale mechanical and tribological properties of coatings deposited on cemented carbide cutting tools and silicon wafer substrates by reactive magnetron sputtering deposition. The surface morphology and microstructure of the coatings were evaluated with an atomic force microscope in dynamic friction mode together with transmission electron microscope imaging. The tribological properties of the coatings were evaluated by pin-on-disc friction testing in dry air, and high-frequency linear-oscillation friction testing under various lubrication conditions. The tribological properties of the multilayer TiAlCrSiN and TiAlSiN coatings were compared with those of a single layer TiAlN coating to evaluate their possible applications to the surfaces of cutting tools. The machining performances of single layer TiAlN, multilayer TiAlSiN, and TiAlCrSiN coated drills were investigated in drilling of carbon steel.

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“…coatings [4,26,27]. Scratch tests were conducted on the coatings and the results are shown in Table 1.…”

Section: Lubrication -Tribology Lubricants and Additivesmentioning

confidence: 99%

Surface Morphology and Tribological Properties of Nanoscale (Ti, Al, Si, C)N Multilayer Coatings Deposited by Reactive Magnetron Sputtering

Wang¹,

Miyake²

2018

Lubrication - Tribology, Lubricants and Additives

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“…Transition metal nitride nanocomposites, such as nc-TiN-SiN have demonstrated exceptional hardness along with high oxidation resistance and thermal stabilitiy [134][135][136][137][138]. They have received considerable attention for the purposes of hard coating materials under extreme conditions, such as industrial grade metal cutting tools.…”

Section: Nanocomposite Multilayersmentioning

confidence: 99%

Theoretical understanding of stability of alloys for hard-coating applications and design

Lind¹

2015

Linköping Studies in Science and Technology. Dissertations

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The performance of modern hard coating materials puts high demands on properties such as hardness, thermal stability and oxidation resistance. These properties not only depend on the chemical composition, but also on the structure of the material on a nanoscale. This kind of nanostructuring will change during use and can be both beneficial and detrimental as materials grown under non-equilibrium conditions transforms under heat treatment or pressure into other structures with significantly different properties. This thesis aims to reveal the physics behind the processes of phase stability and transformations and how this can be utilized to improve on the properties of this class of alloys. This has been achieved through the application of various methods of first-principles calculations and analysis of the results on the basis of thermodynamics and electronic structure theory.Within multicomponent transition metal aluminum nitride alloys (TMAlN) a number of studies have been carried out and presented here on ways of improving high temperature stability and hardness. Most (TMAl)N and TMN prefer a cubic B1 structure while AlN is stable in a hexagonal B4 phase, but for the purposes of hard coatings the metastable cubic B1 AlN phase, isostructural with the TMN phase is desired. It will be shown how the introduction of additional alloying components, such as Cr, into (TiAl)N changes the thermodynamic stability of phases so that new intermediary and metastable phases are formed during decomposition. In the case of such a (CrAl)N phase it is shown to have greater thermodynamic stability in the cubic phase than the pure AlN, resulting in improved high temperature hardness. Also, the importance of treating not just the binodal decomposition through the formation energy relative to end products but also the impact of spinodal decomposition from its second derivative due to the topology of formation energy surfaces is emphasized in the thesis. The impact of pressure on the AlN phase has also been studied through the calculation of a P-T diagram of AlN as part of a (TiAl)N alloy.During the study of chemical alloying of TM components into AlN the alloying of low concentrations of these TM were treated in great detail. What is generally referred to as the AlN phase in decomposition is not entirely pure and can be expected to contain traces of any alloying components, such as Ti and Cr or whatever other metals may be present. Low concentration alloying of Cr, on the order of 5-10% is also shown to be stable with regard to isostructural decomposition. Detailed analysis of the effect of Ti and Cr impurities in AlN has been carried out along with a systematic search of AlN alloyed with small amounts of other TM components. The impact of these impurities on the electronic structure and thermodynamic properties is analyzed and the general trends will be explained through the occupation of impurity states by d-like electrons.iv Theoretical treatment of such impurities is not straightforward however. AlN is an s-p semiconduct...

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“…The nc-TiN-SiN x (nc: nanocrystalline) is considered as a model system in this field and it has been studied extensively. [1][2][3][4] The hardness enhancement in superhard nanocomposites is attributed to a percolative nature of phase segregation, which results in coverage of the transition metal nanocrystals with approximately one monolayer (ML) of the non-polar Si 3 N 4 . The morphology and bonding relationship of a crystalline SiN x tissue phase with nc-TiN is thus debated.…”

confidence: 99%

Anomalous epitaxial stability of (001) interfaces in ZrN/SiNx multilayers

et al. 2014

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Isostructural stability of B1-NaCl type SiN on (001) and (111) oriented ZrN surfaces is studied theoretically and experimentally. The ZrN/SiNx/ZrN superlattices with modulation wavelength of 3.76 nm (dSiNx∼0.4 nm) were grown by dc-magnetron sputtering on MgO(001) and MgO(111). The results indicate that 0.4 nm thin SiNx layers utterly influence the preferred orientation of epitaxial growth: on MgO(001) cube-on-cube epitaxy of ZrN/SiNx superlattices were realized whereas multilayers on MgO(111) surface exhibited an unexpected 002 texture with a complex fourfold 90°-rotated in-plane preferred orientation. Density functional theory calculations confirm stability of a (001) interface with respect to a (111) which explains the anomaly.

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The role of percolation threshold for the control of the hardness and thermal stability of super- and ultrahard nanocomposites

Cited by 132 publications

References 14 publications

Surface Morphology and Tribological Properties of Nanoscale (Ti, Al, Si, C)N Multilayer Coatings Deposited by Reactive Magnetron Sputtering

Surface Morphology and Tribological Properties of Nanoscale (Ti, Al, Si, C)N Multilayer Coatings Deposited by Reactive Magnetron Sputtering

Theoretical understanding of stability of alloys for hard-coating applications and design

Anomalous epitaxial stability of (001) interfaces in ZrN/SiNx multilayers

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