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| 2. |
- Almer, Jonathan, et al.
(författare)
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Microstructural evolution during tempering of arc-evaporated Cr-N coatings
- 2000
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Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films. - : American Vacuum Society. - 0734-2101 .- 1520-8559. ; 18:1, s. 121-130
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Tidskriftsartikel (refereegranskat)abstract
- Cr-N coatings were arc-deposited at 50 and 300 V. The changes in the coating microstructure and phase content during tempering were monitored. As a result, the phase stability and activation energies for defect diffusion were determined as a function of ion energy.
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| 3. |
- Forsén, Rikard, 1985-
(författare)
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Mechanical properties and thermal stability of reactive arc evaporated Ti-Cr-Al-N coatings
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This licentiate thesis reports experimental and theoretical work on the high temperature mechanical properties and the thermal stability of cubic (c)-(Ti-Cr-Al)1-N1 coatings. It is demonstrated that it is possible to tailor and improve the properties of hard nitride coatings by different degrees of multicomponent alloying. When Cr is added to Ti-Al-N the coatings exhibit age hardening up to 1000 ºC which is higher compared to what is observed for Ti-Al-N. In addition, the coatings show a less pronounced hardness decrease when hexagonal (h)-Al-N is formed compared to Ti-Al-N. The improved thermal stability is discussed in terms of a lowered coherency stress and a lowered enthalpy of mixing due to the addition of Cr. When Ti is added to Cr-Al-N the formation and growth of the detrimental h-Al-N phase is suppressed and delayed improving the mechanical properties. This is discussed in terms of kinetic effects where the Ti atoms obstruct the Al diffusion and consequently the growth of h-Al-N precipitates. The microstructure evolution investigated at different stages of spinodal decomposition, coarsening and phase transformations are correlated to the thermal responses and the mechanical hardness of the coatings. Upon annealing up to 1400 ºC the coatings decompose into c-TiN, bcc-Cr and h-AlN. The decomposition takes place via several intermediate phases, c-CrAlN, c-TiCrN and hexagonal (β)-Cr2N. The oxidation resistance of (Tix-Cry-Al60)1-N1 is also investigated and presented for different x/y ratios. The results show that it is possible to generate coatings with both excellent mechanical properties and oxidation resistance improving the functionality in the working temperature range of 850-1100 ºC of for example cutting tools.
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| 4. |
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| 5. |
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| 6. |
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| 7. |
- Odén, Magnus, 1965-, et al.
(författare)
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Microstructure-property relationships in arc-evaporated Cr-N coatings
- 2000
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Ingår i: Thin Solid Films. - 0040-6090 .- 1879-2731. ; 377-378, s. 407-412
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Tidskriftsartikel (refereegranskat)abstract
- Chromium nitride (Cr-N) coatings have received increased attention for tribological applications due to their favorable properties including wear resistance, toughness and oxidation resistance. These properties, in turn, can be strongly influenced by the coating microstructure and residual stress resulting from deposition and subsequent processing operations. In this study these microstructure-property correlations are investigated in Cr-N coatings grown by arc-evaporation. Prominent as-deposited features include formation of metastable amounts of the cubic d-CrN phase, and high levels of compressive residual stress and defect density. During annealing up to 650 ░C the residual stress and defect density decrease substantially, accompanied by a diffusion-based d-CrN to ▀-Cr2N phase transformation and equiaxed grain formation. The effects of these microstructural modifications on the hardness, fracture and wear properties of the coatings are evaluated using a combination of nanoindentation, scratch and pin-on-disk testing. Appreciable changes in these properties are found after annealing, and are correlated to the Cr-N microstructure. As-deposited coating hardness is enhanced by high levels of lattice defect density, with both decreasing concomitantly during annealing. Scratch results show that resistance to cohesive flaking is increased by annealing, suggesting ductility increases via defect annealing and equiaxed grain formation. Finally, the wear rate under dry sliding generally increased with annealing temperature, although wear rates of all Cr-N coatings significantly outperformed TiN tested under identical conditions.
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| 8. |
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| 9. |
- Syed, Bilal, 1977-, et al.
(författare)
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Effect of work function and cohesive energy of the constituent phases of Ti-50 at.% Al cathode during arc deposition of Ti-Al-N coatings
- 2019
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Ingår i: Surface & Coatings Technology. - USA : Elsevier. - 0257-8972 .- 1879-3347. ; 357, s. 393-401
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Tidskriftsartikel (refereegranskat)abstract
- The differences in work function (W.F.) and cohesive energy (C.E.) of the phases constituting the cathode, plays an important role in the formation of the converted layer at its near-surface region during cathodic arc deposition. As a consequence, this also affects the deposition conditions for the coatings. In this study, we explore the effect of W.F. and C.E. of the constituent phases during arc evaporation by utilizing two kinds of customized Ti-50 at.% Al cathodes with different phase compositions. Our results show that during reactive arc evaporation the disparity in W.F. and C.E. among the constituent phases of Ti-50 at.% Al cathodes leads to preferential erosion of the phases with lower W.F. and C.E. The aforementioned preferential erosion begets higher surface roughness on the Ti-50 at.% Al cathode with a wider range of W.F. and C.E. disparity. It is also observed that the thermal conductivity of the Ti-50 at.% Al cathode plays a dominant role in the deposition rate of Ti-Al-N coating. This article also presents how the surface geometry of the cathode in the presence of arc guiding magnetic field significantly influences the microstructure of the deposited coatings.
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| 10. |
- Syed, Bilal, et al.
(författare)
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Morphology and microstructure evolution of Ti-50 at.% Al cathodes during cathodic arc deposition of Ti-Al-N coatings
- 2017
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Ingår i: Journal of Applied Physics. - Melville, New York 11747-4300 : American Institute of Physics (AIP). - 0021-8979 .- 1089-7550. ; 121:24
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Tidskriftsartikel (refereegranskat)abstract
- Today's research on the cathodic arc deposition technique and coatings therefrom primarily focuses on the effects of, e.g., nitrogen partial pressure, growth temperature, and substrate bias. Detailed studies on the morphology and structure of the starting material—the cathode—during film growth and its influence on coating properties at different process conditions are rare. This work aims to study the evolution of the converted layer, its morphology, and microstructure, as a function of the cathode material grain size during deposition of Ti-Al-N coatings. The coatings were reactively grown in pure N2discharges from powder metallurgically manufactured Ti-50 at.% Al cathodes with grain size distribution averages close to 1800, 100, 50, and 10 μm, respectively, and characterized with respect to microstructure, composition, and mechanical properties. The results indicate that for the cathode of 1800 μm grain size the disparity in the work function among parent phases plays a dominant role in the pronounced erosion of Al, which yields the coatings rich in macro-particles and of high Al content. We further observed that a reduction in the grain size of Ti-50 at.% Al cathodes to 10 μm provides favorable conditions for self-sustaining reactions between Ti and Al phases upon arcing to form γ phase. The combination of self-sustaining reaction and the arc process not only result in the formation of hole-like and sub-hole features on the converted layer but also generate coatings of high Al content and laden with macro-particles.
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