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

Franz, Robert; Martín, Francisca Méndez; Hawranek, Gerhard; Polcik, P.

doi:10.1116/1.4941409

Cited by 12 publications

(13 citation statements)

References 36 publications

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“…However, the plasma properties and hence the thin film growth conditions are largely affected by the presence of the cathode surface, which is in a direct contact with plasma. In particular, in the case of CAD the formation of intermetallic phases on the cathode surface due to the exposure to the plasma affects the plasma properties, such as ion charge states and energies [5,6,7].…”

Section: Introductionmentioning

confidence: 99%

Experimental Chemistry and Structural Stability of AlNb3 Enabled by Antisite Defects Formation

et al. 2019

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First-principles evolutionary algorithms are employed to shed light on the phase stability of Al–Nb intermetallics. While the tetragonal Al3Nb and AlNb2 structures are correctly identified as stable, the experimentally reported Laves phase of AlNb3 yields soft phonon modes implying its dynamical instability at 0 K. The soft phonon modes do not disappear even upon elevating the temperature in the simulation up to 1500 K. X-Ray diffraction patterns recorded for our powder-metallurgically produced arc cathodes, however, clearly show that the AlNb3 phase exists. We propose that AlNb3 is dynamically stabilised by ordered antisite defects at the Al sublattice, leading also to a shift of the Nb content from 75 to ∼81 at.%. Unlike the defect-free AlNb3, the antisite-stabilised variant hence falls into the compositional range consistent with our CALPHAD-based phase diagram as well as with the previous reports.

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Section: Introductionmentioning

confidence: 99%

Experimental Chemistry and Structural Stability of AlNb3 Enabled by Antisite Defects Formation

et al. 2019

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“…37,38 This can also be observed for thin Al oxide layers formed at a relatively low inflow rate of O2. 33 However, as suggested in Ref.…”

Section: Process Parameters In the Steady State Regimementioning

confidence: 89%

“…29 -32 Based on this background, arcing from Al-Cr containing cathodes in an oxygen atmosphere is of high technological importance. However, the process can result in formation of Al-rich oxide islands on the cathode surface, and formation of metallic droplets in the coating, 10,22,33,34 which may limit the cathode utilization, and influence the coating properties. However, for an isotropic plasma expansion, the average coating composition matches the virgin cathode composition even when having oxide islands on the cathode.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Si on DC arc plasma generation from Al-Cr and Al-Cr-Si cathodes used in oxygen

Zhirkov

Landälv

Göthelid

et al. 2017

Journal of Applied Physics

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Al2O3 alloyed with Cr is an important material for the tooling industry. It can be synthesized from an arc discharge using Al-Cr cathodes in an oxygen atmosphere. Due to formation of Al-rich oxide islands on the cathode surface, the arc process stability is highly sensitive to the oxygen pressure. For improved stability, the use of Al0.70Cr0.25Si0.05 cathodes has previously been suggested, where Si may reduce island formation. Here, we have investigated the effect of Si by comparing plasma generation and thin film deposition from Al0.7Cr0.3 and Al0.7Cr0.25Si0.05 cathodes. Plasma ion composition, ion energies, ion charge states, neutral species, droplet formation and film composition have been characterized at different O2 flow rate for arc currents of 60 and 90 A. Si and related compounds are detected in plasma ions and in plasma neutrals. Scanning electron microscopy and energy dispersive X-ray analysis show that the cathode composition and the film composition are the same, with Si present in droplets as well. The effect of Si on the process stability, ion energies, and ion charge states is found to be negligible compared to that of the arc current. The latter is identified as the most relevant parameter for tuning the properties of the reactive discharge. The present work increases the fundamental a Corresponding author: igozh@ifm.liu.se, phone +46 730 52 10 12, fax +46 13 137568 2 understanding of plasma generation in a reactive atmosphere, and provides input for the choice of cathode composition and process parameters in reactive DC arc synthesis.

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“…This is due to the extensive oxide island formation on the cathode surface, also referred to as cathode poisoning [118,119]. The oxide island growth is promoted the most for the Al-composition of 50-80 at.% [120], above 85 at.% it can be evaded by the cathode Al-melt solidifying below the formation temperature needed for corundum growth [118]. However, this is the most interesting range, from a production perspective, since the corundum structure can be stabilized by the Cr, while having a high Al-content.…”

Section: Pseudobinary and -Ternary Oxidesmentioning

confidence: 99%

Physical vapor deposition and thermal stability of hard oxide coatings

Landälv

2019

Linköping Studies in Science and Technology. Dissertations

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Cover images Front side from the left-The magnetron sputtering system used in Paper I to deposit Al-V-O-coatings-Si-rich droplet in as-deposited Al-Cr-Si-O coatings adapted from Figure 4b in Paper II. Sirich marked yellow. STEM micrograph and EDX map merged and rotated 90° CCW from paper II for better fit on the front cover.-Crystalline Cr (red) and Zr (green) segregation observed in a Cr-Zr-O coating after vacuum annealing at 810 °C. Adapted from Figure 10b in paper IV. STEM micrograph (top) and EDX map (bottom). Background image on front and backside Light optical microscope image of Al-V-O-coating after annealing in air at 700 °C, adapted to background image with filter and blue color. V2O5 crystals grown on the γ-Al2O3 coating. Magnification of part of Figure 4 in Paper I (sample with 18 at.% metal fraction V, sample F). Interesting for its beauty rather than industrial application.

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

Cited by 12 publications

References 36 publications

Experimental Chemistry and Structural Stability of AlNb3 Enabled by Antisite Defects Formation

Experimental Chemistry and Structural Stability of AlNb3 Enabled by Antisite Defects Formation

Effect of Si on DC arc plasma generation from Al-Cr and Al-Cr-Si cathodes used in oxygen

Physical vapor deposition and thermal stability of hard oxide coatings

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