Surface characterization of aluminum alloy 2017 as a vacuum vessel for nuclear fusion devices

Abstract

The surface characterization of a type 2017 aluminum alloy was performed to examine their potentials for the use of nuclear fusion devices mainly from a view point of vacuum engineering. Three different samples treated with milling (Sample A), discharging (Sample B) and chemical etching (Sample C) were examined in terms of their surface morphology by surface profilometry, scanning electron microscopy, and xenon adsorption. The surface roughness factor was obtained as 5.9, 42.8 and 9.0 for sample A, Sample B and Sample C, respectively. The thicknesses of surface oxide layers were measured by the sputter-AES method as 40 Å, 80 Å and 70 Å for Sample A, Sample B and Sample C, respectively. Outgassing characteristics of these surfaces were measured by a thermal desorption method. H 2O, CO and CO 2 were main outgassing components and the maximum desorption temperature was observed in the range between 110 °C and 160 °C. The surface roughness factor and the thickness of the surface oxide layer were found to be important factors for outgassing characteristics.