Electron-stimulated desorption from polished and vacuum fired 316LN stainless steel coated with Ti-Zr-Hf-V

Journal Article · Sat Nov 01 00:00:00 EDT 2014 · Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films

DOI:https://doi.org/10.1116/1.4897932· OSTI ID:22320370

Valizadeh, Reza; Hogan, Benjamin T.; Hannah, Adrian N. ^[1]

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1. ASTeC, STFC Daresbury Laboratory, Daresbury, Warrington, WA4 4AD Cheshire (United Kingdom)

In this study, two identical 316LN stainless steel tubular samples, which had previously been polished and vacuum-fired and then used for the electron-stimulated desorption (ESD) experiments, were coated with Ti-Zr-Hf-V with different morphologies: columnar and dense. ESD measurement results after nonevaporable getter (NEG) activation to 150, 180, 250, and 350 °C indicated that the values for the ESD yields are significantly (2–20 times) lower than the data from our previous study with similar coatings on nonvacuum-fired samples. Based on these results, the lowest pressure and best long-term performance in particle accelerators will be achieved with a vacuum-fired vacuum chamber coated with dense Ti-Zr-Hf-V coating activated at 180 °C. This is likely due to the following facts: after NEG activation, the hydrogen concentration inside the NEG was lower than in the bulk stainless steel substrate; the NEG coating created a barrier for gas diffusion from the sample bulk to vacuum; the dense NEG coating performed better as a barrier than the columnar NEG coating.

• OSTI ID: 22320370
• Journal Information: Journal of Vacuum Science and Technology. A, Vacuum, Surfaces and Films, Vol. 32, Issue 6; Other Information: (c) 2014 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0734-2101
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACCELERATORS
COATINGS
DESORPTION
DIFFUSION
HAFNIUM COMPOUNDS
HYDROFLUORIC ACID
MORPHOLOGY
NITROGEN ADDITIONS
POLISHING
STAINLESS STEEL-316L
SUBSTRATES
TIN COMPOUNDS
VANADIUM COMPOUNDS
ZIRCONIUM COMPOUNDS