Unprecedented thermal stability of inherently metastable titanium aluminum nitride by point defect engineering

Baben, Moritz to; Hans, Marcus; Primetzhofer, Daniel; Evertz, Simon; Rueß, Holger; Schneider, Jochen M.

doi:10.1080/21663831.2016.1233914

Cited by 82 publications

(53 citation statements)

References 69 publications

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“…The entire experimental details regarding thin film synthesis and ion beam analysis were reported by to Baben et al [17] and a brief summary is provided here. TiAlN thin films were grown reactively by high power pulsed magnetron sputtering [18] on sapphire substrates at a temperature of 300°C from a TiAl target.…”

Section: Experimental Details 21 Materialsmentioning

confidence: 99%

“…The combination of RBS and ToF-ERDA (referred to as RBS/ERDA in the following) resulted in a total measurement uncertainty of 2.5% relative deviation and the absolute composition is (Ti 0.255 Al 0.235 )(N 0.505 O 0.005 ). Moreover, the film exhibits a single phase face-centered cubic crystal structure (space group Fm3 m, NaCl prototype) [17] and a columnar growth morphology with column widths on the order of 100-200 nm [16].…”

Section: Experimental Details 21 Materialsmentioning

confidence: 99%

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Electric field strength-dependent accuracy of TiAlN thin film composition measurements by laser-assisted atom probe tomography

Hans

Schneider

2020

New J. Phys.

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Accurate quantification of absolute concentrations represents a major challenge for atom probe tomography (APT) since the field evaporation process is affected significantly by the measurement parameters. In the present work we investigate systematically the effect of laser pulse parameters on the accuracy of laser-assisted APT for a TiAlN thin film previously quantified by ion beam analysis, combining Rutherford backscattering spectrometry and time-of-flight elastic recoil detection analysis. The electric field strength is estimated from the Al 2+ /Al + charge state ratio for all systematically varied measurement parameters. Subsequently, the absolute concentrations from laser-assisted APT are compared to ion beam analysis data. An increase of the electric field strength from approximately 25-28 V nm −1 improves the accuracy of absolute concentrations measured by laser-assisted APT from 11.4 to 4.1 at% for N, from 8.8 to 3.0 at% for Al and from 2.8 to 0.9 at% for Ti. Our data emphasize that the measurement accuracy of laser-assisted APT for TiAlN is governed by the electric field strength. It is shown that the smallest compositional discrepancies between ion beam analysis and APT are obtained for the maximum electric field strength of approximately 28 V nm −1 at 10 pJ laser pulse energy. This can be rationalized by considering the enhanced ionization of neutral fragments caused by the increased electric field strength.

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Section: Experimental Details 21 Materialsmentioning

confidence: 99%

Section: Experimental Details 21 Materialsmentioning

confidence: 99%

Electric field strength-dependent accuracy of TiAlN thin film composition measurements by laser-assisted atom probe tomography

Hans

Schneider

2020

New J. Phys.

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“…The low onset temperature for spinodal decomposition of overstoichiometric (Ti,Al)Ny is attributed to their existing metal vacancies, which enhance diffusion on the metal sublattice. 18 Diffusion requires energy to overcome the energy barriers for vacancy formation and changing atomic positions.…”

Section: B Thermal Stability Of Ti1-xalxnymentioning

confidence: 99%

“…It was shown that the onset of w-AlN phase transformation in (Ti0.52Al0.48)N0.87 occurred at about 1200 °C, 15 which is about 300 °C higher than what typically is reported for stoichiometric (Ti0.5Al0.5)N thin films. [16][17] Primary decomposition occurs on the metal sublattice and To Baben et al 18 also reports an improved thermal stability of close to stoichiometric (Ti,Al)Ny (y ≈ 1) as compared to over-stoichiometric (Ti,Al)Ny (y > 1). The faster decomposition in over-stoichiometric (y > 1)…”

Section: Introductionmentioning

confidence: 99%

Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage

Calamba

Schramm

Johansson-Jöesaar

et al. 2017

Journal of Applied Physics

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Aspects on the phase stability and mechanical properties of nitrogen deficient (Ti0.54Al0.46)N-y alloys were investigated. Solid solution alloys of (Ti,Al)N were grown by cathodic arc deposition. The kinetic energy of the impinging ions was altered by varying the substrate bias voltage from -30V to -80 V. Films deposited with a high bias value of -80V showed larger lattice parameter, finer columnar structure, and higher compressive residual stress resulting in higher hardness than films biased at -30V when comparing their as-deposited states. At elevated temperatures, the presence of nitrogen vacancies and point defects (anti-sites and self-interstitials generated by the ion-bombardment during coating deposition) in (Ti0.54Al0.46)N-0.87 influence the driving force for phase separation. Highly biased nitrogen deficient films have point defects with higher stability during annealing, which cause a delay of the release of the stored lattice strain energy and then accelerates the decomposition tendencies to thermodynamically stable c-TiN and w-AlN. Low biased nitrogen deficient films have retarded phase transformation to w-AlN, which results in the prolongment of age hardening effect up to 1100 degrees C, i.e., the highest reported temperature for Ti-Al-N material system. Our study points out the role of vacancies and point defects in engineering thin films with enhanced thermal stability and mechanical properties for high temperature hard coating applications. Published by AIP Publishing.

Funding Agencies|European Unions Erasmus Mundus doctoral program in Materials Science and Engineering (DocMASE); Swedish Research Council [621-2012-4401]; Swedish government strategic research area grant AFM - SFO MatLiU [2009-00971]; VINNOVA [2013-02355]; DFG; federal state government of Saarland [INST 256/298-1 FUGG]; European Regional Development Fund [AME-Lab C/4-EFRE-13/2009/Br]

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“…7 In conventional dc magnetron sputter (DCMS) deposition, reported kinetic AlN solubility limits in c-(TM)1-xAlxN systems for growth temperatures Ts ~ 500 °C range from x = 0.3 for Zr1-xAlxN, 8 to 0.5 for Ti1-xAlxN, 9 and 0.67 for Cr1-xAlxN compounds, 10 with some uncertainty related to the sensitivity of the analysis method used to detect precipitation of the w-AlN phase. 11,12 Supersaturated single-phase alloys with higher Al content are typically obtained by cathodic arc deposition, with x = 0.50 for ZrAlN, 13 0.66 for TiAlN, 14,15,16 and 0.70 for CrAlN. The VAlN system is relatively less explored, with only few publications, 17,18,19 yet potentially useful predominantly due to the combination of high hardness and low friction coefficient, which makes it a promising candidate for applications as a wearresistant coating in, for example, deep drawing of high-strength steels.…”

Section: Introductionmentioning

confidence: 99%

Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation

Greczyński

Mráz

Hans

et al. 2017

Journal of Applied Physics

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Modern applications of refractory ceramic thin films, predominantly as wear-protective coatings on cutting tools and on components utilized in automotive engines, require a combination of excellent mechanical properties, thermal stability, and oxidation resistance. Conventional design approaches for transition metal nitride coatings with improved thermal and chemical stability are based on alloying with Al. It is well known that the solubility of Al in NaCl-structure transition metal nitrides is limited. Hence, the great challenge is to increase the Al concentration substantially while avoiding precipitation of the thermodynamically favored wurtzite-AlN phase, which is detrimental to mechanical properties. Here, we use VAlN as a model system to illustrate a new concept for the synthesis of metastable single-phase NaCl-structure thin films with the Al content far beyond solubility limits obtained with conventional plasma processes. This supersaturation is achieved by separating the film-forming species in time and energy domains through synchronization of the 70-μs-long pulsed substrate bias with intense periodic fluxes of energetic Al+ metal ions during reactive hybrid high power impulse magnetron sputtering of the Al target and direct current magnetron sputtering of the V target in the Ar/N2 gas mixture. Hereby, Al is subplanted into the cubic VN grains formed by the continuous flux of low-energy V neutrals. We show that Al subplantation enables an unprecedented 42% increase in metastable Al solubility limit in V1-xAlxN, from x = 0.52 obtained with the conventional method to 0.75. The elastic modulus is 325 ± 5 GPa, in excellent agreement with density functional theory calculations, and approximately 50% higher than for corresponding films grown by dc magnetron sputtering. The extension of the presented strategy to other Al-ion-assisted vapor deposition methods or materials systems is straightforward, which opens up the way for producing supersaturated single-phase functional ceramic alloy thin films combining excellent mechanical properties with high oxidation resistance.

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Unprecedented thermal stability of inherently metastable titanium aluminum nitride by point defect engineering

Cited by 82 publications

References 69 publications

Electric field strength-dependent accuracy of TiAlN thin film composition measurements by laser-assisted atom probe tomography

Electric field strength-dependent accuracy of TiAlN thin film composition measurements by laser-assisted atom probe tomography

Enhanced thermal stability and mechanical properties of nitrogen deficient titanium aluminum nitride (Ti0.54Al0.46Ny) thin films by tuning the applied negative bias voltage

Unprecedented Al supersaturation in single-phase rock salt structure VAlN films by Al+ subplantation

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