Near-surface chemistry in Zr2Fe and ZrVFe studied by means of x-ray photoemission spectroscopy: A temperature-dependent study

Kovač, Janez; Sakho, O.; Manini, Paolo; Sancrotti, M.

doi:10.1116/1.1308591

Cited by 13 publications

(8 citation statements)

References 18 publications

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“…As shown in Figure 3 a–c, the evolution with temperature of the XPS spectra associated with the Ti 2p orbital of the Ti upper-layer NEGs and the one associated with the Zr 3d orbital of the Zr upper-layer NEG have two regimes. In the first regime from the as-deposited NEG sample to the activation at 275 °C, the Ti 2p (Zr 3d) spectrum evolution was mainly controlled by the decrease of the doublet peak Ti 4+ (Zr 4+ ) of bending energy (BE):

= 458.8 eV,

= 182.8 eV related to the TiO 2 (ZrO 2 ) oxide, accompanied simultaneously with, both, an increase in the Ti x+<4 (Zr x+<4 ) doublet peaks related to TiO x<2 (ZrO x<2 ) suboxides [ 13 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ] and an emergence of a metal hydroxide Ti(OH) 2 (Zr(OH) 2 ) doublet peak located at higher bending energies (

= 459.3 eV (

= 183.4 eV)) [ 28 , 29 , 30 , 31 ]. In the second regime, over 275 °C and up to 450 °C, the Ti 2p (Zr 3d) spectrum evolution was mainly controlled by a simultaneous decrease of metal-oxide, metal-hydroxide, and metal-suboxide, accompanied with a significant increase of doublet peak related to the metallic state Ti 0 (Zr 0 ) with a BE of

= 454 ± 0.2 eV (BE of

= 178.9 eV) as well as some contaminant-based phases peaks such as carbides TiC, TiC–O (ZrC, ZrC–O) [ 13 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Development and Characterization of Non-Evaporable Getter Thin Films with Ru Seeding Layer for MEMS Applications

2018

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Mastering non-evaporable getter (NEG) thin films by elucidating their activation mechanisms and predicting their sorption performances will contribute to facilitating their integration into micro-electro-mechanical systems (MEMS). For this aim, thin film based getters structured in single and multi-metallic layered configurations deposited on silicon substrates such as Ti/Si, Ti/Ru/Si, and Zr/Ti/Ru/Si were investigated. Multilayered NEGs with an inserted Ru seed sub-layer exhibited a lower temperature in priming the activation process and a higher sorption performance compared to the unseeded single Ti/Si NEG. To reveal the gettering processes and mechanisms in the investigated getter structures, thermal activation effect on the getter surface chemical state change was analyzed with in-situ temperature XPS measurements, getter sorption behavior was measured by static pressure method, and getter dynamic sorption performance characteristics was measured by standard conductance (ASTM F798–97) method. The correlation between these measurements allowed elucidating residual gas trapping mechanism and prediction of sorption efficiency based on the getter surface poisoning. The gettering properties were found to be directly dependent on the different changes of the getter surface chemical state generated by the activation process. Thus, it was demonstrated that the improved sorption properties, obtained with Ru sub-layer based multi-layered NEGs, were related to a gettering process mechanism controlled simultaneously by gas adsorption and diffusion effects, contrarily to the single layer Ti/Si NEG structure in which the gettering behavior was controlled sequentially by surface gas adsorption until reaching saturation followed then by bulk diffusion controlled gas sorption process.

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= 458.8 eV,

= 459.3 eV (

= 454 ± 0.2 eV (BE of

= 178.9 eV) as well as some contaminant-based phases peaks such as carbides TiC, TiC–O (ZrC, ZrC–O) [ 13 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ].…”

Section: Resultsmentioning

confidence: 99%

Development and Characterization of Non-Evaporable Getter Thin Films with Ru Seeding Layer for MEMS Applications

2018

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“…24 In this case, the fraction of getter surface able to pump gases already during the bake-out will be larger and so the overall pumping speed. It is worth noticing that the above results are not optimized.…”

Section: Discussionmentioning

confidence: 99%

Combination of compact nonevaporable getter and small ion pumps for ultrahigh vacuum systems

Park

Chung

Manini

2011

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

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Articles you may be interested inCharacterization of alkali metal dispensers and non-evaporable getter pumps in ultrahigh vacuum systems for cold atomic sensors J. Vac. Sci. Technol. A 30, 061602 (2012); 10.1116/1.4757950 Efficient combining of ion pumps and getter-palladium thin films Description of a dust particle detection system and measurements of particulate contamination from shock, gate valve, and ion pump under ultrahigh vacuum conditions Rev.The rapid pumpdown of ultrahigh vacuum ͑UHV͒ systems, achieved with a very short and low temperature baking or even without baking, is appealing in a variety of research and industrial applications. The use of small volume, compact pumps delivering very high pumping speed is also attractive since it allows minimizing the overall size and weight of the vacuum system, simplifying its design. In the present article, the authors report the results of the pumping experiments carried out on a vacuum chamber pumped by a compact nonevaporable getter ͑NEG͒ pump ͑Capacitorr D 400-2 ® model, SAES Getters SpA, Italy͒ and by a small sputter ion pump ͑SIP͒. To measure the effective contribution of the NEG to the overall pumping, vacuum tests were carried out in a wide range of situations, with/without NEG pump, with/without baking, and changing the pumping speed of the SIP from 60 to 10 l/s ͑N 2 ͒. Significantly lower pressures and faster pumping could be achieved using the NEG pump. Base pressures of low 10 −11 mbar could be obtained in the authors' experimental system with the compact NEG assisted by the 10 l/s SIPs after a 48 h bake-out. The results also show that the system with NEG reached 10 −11 mbar after a very short ͑few hours͒ bake-out. The base pressure was 1 ϫ 10 −10 mbar with 60 l/s SIP alone after a 48 h bake-out, whereas it was 7.9ϫ 10 −11 mbar when combined with the NEG, a better result after only 2 h bake-out. This is quite a remarkable decrease in the bake-out time of a UHV system. It is worthwhile to note that UHV could also be achieved with the NEG even in a fully unbaked system. The pressure of 8 ϫ 10 −9 mbar reached with the SIP alone dropped to 3.9ϫ 10 −10 mbar after adding the NEG. The other interesting result of the NEG-based system is that the pressure increase is much slower when the SIP is switched off. This is also a good characteristic, required for portable vacuum devices, such as UHV suitcases and more generally for systems hosting sensitive materials or components, which can be affected by the pressure increase following a power interruption.

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“…Zr 2 Fe was found to be effective in scavenging hydrogen down to very low concentrations and can be used, for example, to prevent the release of tritiated heavy water [4] or for fuel purification in a fusion fuel cycle [5]. It is used for a variety of applications, like gas purification from hydrogen and its isotopes [6][7][8][9], hydrogen storage [10], safeguarding of hydrogen high pressure vessels and hydrogen retrieval from several gas mixtures [6]. It has been found that this alloy can absorb hydrogen up to 46% of its volume.…”

Section: Introductionmentioning

confidence: 99%

The interaction of Zr2Fe surface with O2 and H2O at the temperature range 300–770K

Zalkind¹,

Nahmani²,

Shamir³

2010

Journal of Alloys and Compounds

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Near-surface chemistry in Zr2Fe and ZrVFe studied by means of x-ray photoemission spectroscopy: A temperature-dependent study

Cited by 13 publications

References 18 publications

Development and Characterization of Non-Evaporable Getter Thin Films with Ru Seeding Layer for MEMS Applications

Development and Characterization of Non-Evaporable Getter Thin Films with Ru Seeding Layer for MEMS Applications

Combination of compact nonevaporable getter and small ion pumps for ultrahigh vacuum systems

The interaction of Zr2Fe surface with O2 and H2O at the temperature range 300–770K

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