An x-ray photoemission spectroscopy investigation of thermal activation induced changes in surface composition and chemical bonds of two gettering alloys: Zr sub 2 Fe versus Zr sub 57 V sub 36 Fe sub 7

Journal Article · Fri Mar 01 00:00:00 EST 1991 · Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA)

DOI:https://doi.org/10.1116/1.577518· OSTI ID:6186319

Sancrotti, M; Trezzi, G ^[1]; Manini, P ^[2]

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1. Istituto di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy (IT)
2. SAES Getters S.p.A., Via Gallarate 215, 20151 Milano, Italy (IT)

We report comparative XPS ({ital h}{nu}=1253.6 eV) core level (Zr 3{ital d}; C 1{ital s}; O 1{ital s}; Fe 2{ital p}; V 2{ital p}) results from two relevant gettering alloys: Zr{sub 2}Fe and Zr{sub 57}V{sub 36}Fe{sub 7}. The samples were studied as-received (after in-air fracturing of bulk ingots) and after different annealing treatments (up to 700 {degree}C) performed in ultrahigh vacuum. With increasing temperature both alloys show a progressive dissolution of Zr oxides, an increase in the metallic character of the surface, the gradual loss of C based adsorbates, and a progressive increase in the surface Zr content and at the expense of the C concentration. At temperatures in the range 300--550 {degree}C a fraction of the C atoms form metallic carbides. OH-based groups are depleted from the surface at low temperatures (200 {degree}C), resulting in a sizable decrease of the near surface O content, while a nearly constant O concentration is found at intermediate and high temperatures. Only minor changes are observed for the near surface concentrations of Fe in Zr{sub 2}Fe and Fe and V in Zr{sub 57}V{sub 36}Fe{sub 7} as a function of temperature. The two alloys show strong differences in the activation kinetics of these changes, with surface metallization being initiated at lower temperatures and proceeding faster in Zr{sub 57}V{sub 36}Fe{sub 7}. Metallic carbides are found to almost completely dissolve in Zr{sub 57}V{sub 36}Fe{sub 7} at 600--700 {degree}C, while they are retained even at high temperatures in Zr{sub 2}Fe. The kinetic differences determined via XPS are consistent with the differences in gettering behavior of Zr{sub 2}Fe and Zr{sub 57}V{sub 36}Fe{sub 7}.

• OSTI ID: 6186319
• Journal Information: Journal of Vacuum Science and Technology, A (Vacuum, Surfaces and Films); (USA), Vol. 9:2; ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
36 MATERIALS SCIENCE
IRON ALLOYS
CHEMICAL BONDS
CHEMICAL COMPOSITION
VANADIUM ALLOYS
ZIRCONIUM BASE ALLOYS
ADSORPTION
ANNEALING
CARBIDES
EXPERIMENTAL DATA
GETTERING
HIGH TEMPERATURE
PHOTOELECTRON SPECTROSCOPY
SURFACE PROPERTIES
ULTRAHIGH VACUUM
VERY HIGH TEMPERATURE
ALLOYS
CARBON COMPOUNDS
DATA
ELECTRON SPECTROSCOPY
HEAT TREATMENTS
INFORMATION
NUMERICAL DATA
SORPTION
SPECTROSCOPY
ZIRCONIUM ALLOYS
426000* - Engineering- Components
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360104 - Metals & Alloys- Physical Properties
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