Pulsed plasma-assisted PVD sputter-deposited alumina thin films

Schütze, Andreas; Quinto, Dennis T.

doi:10.1016/s0257-8972(02)00705-3

Cited by 59 publications

(27 citation statements)

References 17 publications

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“…9b-e, where depositions at −150 V substrate bias potential at 200-500 o C show presence of the γ -phase. To our knowledge, the lowest temperature previously reported for the formation of this phase is 290-350 o C. (9) Based on recent reports on the application of γ -phase alumina in metal cutting (4) and steel forming, (29) underlining the (not understood) stability of these thin films, the above reported synthesis route may be of technological interest for the deposition of heat sensitive substrates. (24) ).…”

Section: Film Microstructurementioning

confidence: 96%

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Effect of Ion Energy on Structure and Composition of Cathodic Arc Deposited Alumina Thin Films

Rosén

Mráz

Kreißig

et al. 2005

Plasma Chem Plasma Process

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The effect of energy supplied to the growing alumina film on the composition and structure has been investigated by varying substrate temperature and substrate bias potential. The constitution and composition were studied by X-ray diffraction and elastic recoil detection analysis, respectively. Increasing the substrate bias potential from −50 to −100 V caused the amorphous or weakly crystalline films to evolve into stoichiometric, crystalline films with a mixture of the α-and γ -phase above 700 o C, and γ -phase dominated films at temperatures as low as 200 o C. All films had a grain size of <10 nm. The combined constitution and grain size data is consistent with previous work stating that γ -alumina is thermodynamically stable at grain sizes <12 nm [McHale et al., Science 277, 788 (1997)]. In order to correlate phase formation with synthesis conditions, the plasma chemistry and ion energy distributions were measured at synthesis conditions. These results indicate that for a substrate bias potential of −50 V, ion energies in excess of 100 eV are attained, both from a high energy tail and the accelerated ions with charge >1. These results are of importance for an increased understanding of the evolution of film composition and microstructure, also providing a pathway to γ -alumina growth at temperatures as low as 200 o C.

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Section: Film Microstructurementioning

confidence: 96%

“…(3) The thermodynamically stable phase is α-alumina, and is as such often favoured in high temperature or high load applications. However, also the metastable κ-and γ -alumina have proven to be a suitable alternatives for wear resistant coatings (4) as well as in metal cutting applications, (4,5) respectively.…”

Section: Introductionmentioning

confidence: 99%

Effect of Ion Energy on Structure and Composition of Cathodic Arc Deposited Alumina Thin Films

Rosén

Mráz

Kreißig

et al. 2005

Plasma Chem Plasma Process

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“…In order to obtain γ-Al2O3 without amorphous phase, by means of reactively pulsed DC sputtering, a substrate temperature of at least 500 °C was needed as well as high power densities (with floating bias voltage) [29]. Similar deposition temperatures for reactive pulsed DC processes has been reported by several authors [16,17,30,31]. With RF-sputtering it has been obtained at 450 °C -500 °C [32,33].…”

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confidence: 65%

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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“…These values are significantly higher than those of refractory ceramics typically used for the surface modification of orthopedic biomaterials. For example, typical nanohardness and Young's modulus values for alumina films are 25 GPa and 350 GPa, respectively [20].…”

Section: Resultsmentioning

confidence: 99%

Hydroxyapatite–diamondlike carbon nanocomposite films

Narayan

2005

Materials Science and Engineering: C

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Pulsed plasma-assisted PVD sputter-deposited alumina thin films

Cited by 59 publications

References 17 publications

Effect of Ion Energy on Structure and Composition of Cathodic Arc Deposited Alumina Thin Films

Effect of Ion Energy on Structure and Composition of Cathodic Arc Deposited Alumina Thin Films

Thin Film and Plasma Characterization of PVD Oxides

Hydroxyapatite–diamondlike carbon nanocomposite films

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