An AES study of surface oxidation of zirconium

Tomita, M.; Tanabe, T.; Imoto, Shôsuke

doi:10.1016/0039-6028(89)90066-6

Cited by 32 publications

(10 citation statements)

References 18 publications

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“…In particular the zirconium and carbon line-shape changes provide indications for the degree of activation. Tomita et al 6 found that the shape of the MNV Zr line correlates with the amount of oxygen adsorbed onto the surface of Zr. A peak at 141 eV grows when the surface gets more and more oxidised and is characteristic for Zr in ZrO 2 .…”

Section: Surface Composition Analysis By Auger Electron Spectroscopy mentioning

confidence: 99%

Lowering the activation temperature of TiZrV non-evaporable getter films

Prodromides

Scheuerlein

Taborelli

2001

Vacuum

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In order to reduce the activation temperature of the TiZrV alloy, thin films of various compositions were produced by three-cathode magnetron sputtering on stainless steel substrates. For the characterisation of the activation behaviour the surface chemical composition has been monitored by Auger Electron Spectroscopy (AES) during specific in situ thermal cycles. The volume elemental composition of the film has been measured by Energy Dispersive X-ray spectroscopy (EDX) and the morphology (crystal structure and size of the crystallites) has been investigated by X-ray diffraction (XRD). The criteria indicating the sample quality and its dependence on film structure and chemical composition are presented and discussed.Keywords: getter, activation, NEG, titanium alloy, vanadium alloy, zirconium alloy, ternary alloys, thin film Paper presented at the 6th European Vacuum Conference University Lyon 1, Campus La Doua/IPNL, Lyon, France 7-10 December 1999 To be published in "Vacuum" Geneva, SwitzerlandDécembre 1999 -2 - INTRODUCTIONIn the context of the technical developments for the construction of the Large Hadron Collider (LHC) at CERN, a systematic study has been undertaken in order to produce suitable non-evaporable getter films (NEG). Many coatings composed of various elements have been produced and tested, which all exhibited activation temperature below 400 °C 1,2 . The lowest activation temperature, 200 qC for a 24-hour heating, has been obtained with a TiZrV alloy thin film 3 . A complete review of the results obtained with this coating is presented separately at this conference 4 .In the present study, thin films of titanium-zirconium-vanadium ternaries with various compositions have been produced and characterised by structural and chemical analyses in order to possibly further decrease the activation temperature. Characterisation by surface analytical techniques has been chosen, namely Auger Electron Spectroscopy (AES). It was preferred to other techniques because it results in faster sample production and characterisation. EXPERIMENTAL Coating deposition methodNEG thin films are produced by sputtering, because this deposition method provides an easy way to deposit an uniform coating on complex and narrow access chambers, and it can be applied to most metals and their alloys. The initially adopted sputtering system makes use of a composite cathode obtained by twisting together wires of different materials 1 . However, this configuration limits the range of achievable elemental compositions. In order to have a wider choice of compositions a three magnetron sputtering system has been adopted, in which the three cathodes are independently supplied. All our samples have been produced using the same parameters: a total base pressure after bake-out in the 10 -7 Pa range, an argon discharge pressure of 7 x 10 -1 Pa, non heated substrates (T d 90 qC), water cooled cathodes, constant magnetic fields due to two SmCo magnets (a central Sm 2 Co 17 circular magnet surrounded by a SmCo 5 toroidal magnet).The powe...

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Section: Surface Composition Analysis By Auger Electron Spectroscopy mentioning

confidence: 99%

Lowering the activation temperature of TiZrV non-evaporable getter films

Prodromides

Scheuerlein

Taborelli

2001

Vacuum

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“…A layer of crystalline Cu 2 O and CuO oxides with a thickness of $5 nm was found to be formed on the surface of Cu by room-temperature oxidation [26,27]. Oxidation of Zr at room temperature involves three stages: the initial solution of oxygen in a-Zr, the nucleation of ZrO 2 on the surface, and the further growth of the ZrO 2 layer [28]. The growth rate of crystalline oxides on a non-flat surface was found to be non-uniform [29,30] but its behavior in the glassy state is not so clear.…”

Section: Introductionmentioning

confidence: 98%

Bulk metallic glassy surface native oxide: Its atomic structure, growth rate and electrical properties

et al. 2015

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“…Surface analysis by electron spectroscopy allows to follow the variation of the surface composition during the NEG activation process. Both, AES and XPS have been used for various studies of bulk getters [2] [3] [4] [5] and also to monitor the activation of TiZrV NEG thin film coatings [6] [7].…”

Section: Introductionmentioning

confidence: 99%

The characterisation of non-evaporable getters by Auger electron spectroscopy: analytical potential and artefacts

Prodromides

Scheuerlein

Taborelli

2002

Applied Surface Science

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The surfaces of getter materials are particularly difficult to analyse because of their high chemical reactivity. The results obtained can be strongly influenced by the experimental setup and procedures. In this paper the experimental influence on the Auger electron spectroscopy results is discussed, based on the measurements of more than 100 different non-evaporable getter (NEG) materials. There are four typical changes in the Auger electron spectra when a NEG becomes activated. The oxygen peak intensity decreases, the shape of the metal peaks changes, the carbon peak shape changes shape and intensity and a chlorine peak occurs. All these changes are affected by instrumental artefacts. The Zr-MNV peak shape changes occurring during the reduction of ZrO 2 are well suited to determine the onset of NEG activation, while the slope with which the O-KLL peak intensity decreases in a certain temperature range is a better criterion for the determination of the temperature at which activation is complete. The O-KLL intensity and the Zr-MNV peak shape are influenced by the adsorption of residual gas, in particular of H 2 O, and by electron stimulated desorption of oxygen. The C-KLL peak shape changes from "graphitic" to "carbidic" when the NEG becomes activated. The changes of the C-KLL intensity observed in the present study are mainly caused by the transfer of carbon contamination from the sample holder onto the sample during NEG heating. The presence of chlorine at submonolayer coverage is easily detected by AES but not by XPS. The temperature at which a Cl-LMM peak appears in the NEG Auger electron spectra is correlated with the onset of NEG activation. The Cl-LMM intensity is strongly reduced by electron irradiation, in particular when AES measurements are carried out on hot samples.

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An AES study of surface oxidation of zirconium

Cited by 32 publications

References 18 publications

Lowering the activation temperature of TiZrV non-evaporable getter films

Lowering the activation temperature of TiZrV non-evaporable getter films

Bulk metallic glassy surface native oxide: Its atomic structure, growth rate and electrical properties

The characterisation of non-evaporable getters by Auger electron spectroscopy: analytical potential and artefacts

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