Correlation between target surface and layer nucleation in the synthesis of Al–Cr–O coatings deposited by reactive cathodic arc evaporation

Ramm, J.; Neels, Antonia; Widrig, Beno; Döbeli, M.; Vieira, Leandro de Abreu; Dommann, Alex; Rudigier, H.

doi:10.1016/j.surfcoat.2010.08.152

Cited by 47 publications

(26 citation statements)

References 27 publications

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“…The thickness of the modified layer was proportional to the heat conductivity of the cathode material. More recently, the surfaces of a series of cathode materials used for the synthesis of hard coatings has been studied including Al-Cr [20,21], Ti-Si [22,23] and Ti-Al [10,24] as well as Ti 3 SiC 2 [25] and Al-Cr-Si [26]. The Al-Cr-based systems were exposed to an arc plasma in O 2 atmosphere, whereas the Ti-based cathodes were used in N 2 containing arc discharges.…”

Section: Introductionmentioning

confidence: 99%

Erosion behavior of composite Al-Cr cathodes in cathodic arc plasmas in inert and reactive atmospheres

Franz

Martín

Hawranek

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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AlxCr1−x composite cathodes with Al contents of x = 0.75, 0.5 and 0.25 were exposed to cathodic arc plasmas in Ar, N2 and O2 atmospheres and their erosion behaviour was studied. Cross-sectional analysis of the elemental distribution of the near-surface zone in the cathodes by scanning electron microscopy revealed the formation of a modified layer for all cathodes and atmospheres. Due to intermixing of Al and Cr in the heat-affected zone, intermetallic Al-Cr phases formed as evidenced by X-ray diffraction analysis. Cathode poisoning effects in the reactive N2 and O2 atmospheres were non-uniform as a result of the applied magnetic field configuration. With the exception of oxide islands on Al-rich cathodes, reactive layers were absent in the circular erosion zone, while nitrides and oxides formed in the less eroded centre region of the cathodes.

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Section: Introductionmentioning

confidence: 99%

Erosion behavior of composite Al-Cr cathodes in cathodic arc plasmas in inert and reactive atmospheres

Franz

Martín

Hawranek

et al. 2016

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…This is due to the extensive oxide island formation on the cathode surface, also referred to as cathode poisoning [78,79]. Adding 5 at % Si to the cathode was reported to improve the cathode erosion and to reduce the oxide island formation.…”

Section: Pseudo-binary and -Ternary Oxidesmentioning

confidence: 99%

Thin Film and Plasma Characterization of PVD Oxides

Landälv¹

2017

Linköping Studies in Science and Technology. Dissertations

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The state-of-the-art tools for machining metals are primarily based on a metal-ceramic composite (WC-Co) coated with different combinations of carbide, nitride and oxide coatings. Combinations of these coating materials are optimized to withstand specific wear conditions. Oxide coatings are especially desired because of their possible high hot hardness, chemical inertness with respect to the workpiece, and their low friction.This thesis deals with process and coating characterization of new oxide coatings deposited by physical vapor deposition (PVD) techniques, focusing on the Cr-Zr-O and Al-Cr-Si-O systems.The thermal stability of α-Cr0.28Zr0.10O0.61 deposited by reactive radio frequency (RF)-magnetron sputtering at 500 °C was investigated after annealing up to 870 °C. The annealed samples showed transformation of α-(Cr,Zr)2O3 and amorphous ZrOx-rich areas into tetragonal ZrO2 and bcc Cr. The instability of the α-(Cr,Zr)2O3 is surprising and possibly related to the annealing being done under vacuum, facilitating the loss of oxygen. The stabilization of the room temperature metastable tetragonal ZrO2 phase, due to surface energy effects, may prove to be useful for metal cutting applications. The observed phase segregation of α-(Cr,Zr)2O3 and formation of tetragonal ZrO2 with corresponding increase in hardness for this pseudo-binary oxide system also opens up design routes for pseudo-binary oxides with tunable microstructural and mechanical properties.The inherent difficulties of depositing insulating oxide films with PVD, demanding a closed circuit, makes the investigation of process stability an important part of this research. In this context, we investigated the influence of adding small amount of Si in Al-Cr cathode on plasma characteristics, process parameters, and coating properties. Si was chosen here due to a previous study showing improved erosion behavior of Al-Cr-Si over pure Al-Cr cathode without Si incorporation in the coating.This work shows small improvements in cathode erosion and process stability (lower pressure and cathode voltage) when introducing 5 at % Si in the Al70Cr30-cathode. This also led to fewer droplets at low cathode current and intermediate O2 flow. A larger positive effect on cathode erosion was observed with respect to cleaning the cathode from oxide contamination by increasing cathode current with 50%. However, higher cathode current also resulted in increased amount of droplets in the coating which is undesirable. Through plasma analysis the presence of volatile SiO species could be confirmed but the loss of Si through volatile SiO species was negligible, since the coating composition matched the cathode composition. The positive effect of added Si on the process stability at the cathode surface should be weighed against Si incorporation in the coating. This incorporation may or may not be beneficial for the final application since literature states that Si promotes the metastable γ-phase over the thermodynamically stable α-phase of pure Al2O3, contrary to the effect o...

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“…Physical Vapour Deposition (PVD) of ternary Cr-Al-O and quaternary Cr-Al-O-N coating formulations have received a particular attention from the tooling and metal component industries due to its potential to attain the mechanical properties of super hard materials such as corundum -Al2O3 [1][2][3][4][5][6]. The idea is based on the capability of the eskolaite (-Cr2O3) crystalline structure to act as a template for the growth of the corundum phase -Al2O3, at temperature ranges permitting the deposition on tool steels, i.e.…”

Section: Introductionmentioning

confidence: 99%

“…The idea is based on the capability of the eskolaite (-Cr2O3) crystalline structure to act as a template for the growth of the corundum phase -Al2O3, at temperature ranges permitting the deposition on tool steels, i.e. typically 450ºC-550ºC [2][3][4][5][6][7]. All this is feasible because of two main reasons; the structure of eskolaite -Cr2O3 has the same space group as corundum -Al2O3, and on the other hand the eskolaite -Cr2O3 can be synthesized at the application working temperatures of tool steels.…”

Section: Introductionmentioning

confidence: 99%

Chemical and mechanical stability of air annealed cathodic arc evaporated CrAlON coatings

Almandoz

Fuentes

Fernández

et al. 2018

Surface and Coatings Technology

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This study reports the synthesis and characterization of ternary Cr-Al-O and quaternary Cr-Al-ON coatings deposited by cathodic arc physical vapour deposition, for various nitrogen and oxygen mass flow ratios during the growth process. The composition, microstructure, indentation hardness and modulus of the films have been characterized by scanning electron microscopy, electron probe micro-analysis, X-ray diffraction, and nanoindentation techniques. The evolution of the microstructure and mechanical properties of the coatings after ambient air annealing from 800ºC up to 1100 ºC have been investigated. As the oxygen to nitrogen mass flow increases, the as-deposited coatings exhibit lower hardness, higher roughness, lower crystallinity and a more marked columnar structure. At oxygen to nitrogen mass flow ratios bigger than 10/90, the coatings exhibit a stoichiometry of the type (CrAl)2+O3-. Only the coatings with an oxygen to nitrogen mass flow ratio smaller than 10/90 retained nitrogen in their compositions. In all cases, the coatings developed a cubic fcc lattice structure. After annealing at 1100 ºC the resulting microstructure showed a clear dependency upon the initial composition of the films. The evolution of the microstructure during the high temperature tests, as well as the analysis of the nanoindentation hardness, composition and thickness also provided valuable information about the combined effects of the thermal stability and the oxidation of the deposited coatings.

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Correlation between target surface and layer nucleation in the synthesis of Al–Cr–O coatings deposited by reactive cathodic arc evaporation

Cited by 47 publications

References 27 publications

Erosion behavior of composite Al-Cr cathodes in cathodic arc plasmas in inert and reactive atmospheres

Erosion behavior of composite Al-Cr cathodes in cathodic arc plasmas in inert and reactive atmospheres

Thin Film and Plasma Characterization of PVD Oxides

Chemical and mechanical stability of air annealed cathodic arc evaporated CrAlON coatings

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