Thermal desorption measurements for aluminum alloy 6063 and stainless steel 304

Abstract

A comparison of thermal outgassing rates of aluminum alloy and stainless steel vacuum chambers AIP Conf. Proc. 171, 244 (1988); 10.1063/1.37306 Outgassing behavior of A6063EX aluminum alloy and SUS 304 stainless steel J. Vac. Sci. Technol. A 5, 3422 (1987); 10.1116/1.574206 A comparison of outgassing rate of 304 stainless steel and A6063EX aluminum alloy vacuum chamber after filling with waterThis presentation describes thermal desorption spectroscopy from two materials: ultrasonically chemically cleaned aluminum alloy 6063 and stainless steel 304. Some new conclusions on vacuum and surface characterization are obtained. ( 1 ) On the surface of 304, there exist two types of adsorption states which desorb at 328 and 366 K, originating from, air exposure and water rinse separately; the corresponding desorption activation energies E are 22 and 25 kcallmol. For the unbaked sample, water is the major desorbed species and the quantities which originate from water rinse are two times from air exposure. (2) On the surface 6063, there exists only one type of adsorption state for water, which desorbs at 353 K; E is 24 kcallmol, regardless of whether it is from air exposure or water rinse. The quantity adsorbed is twice that on the surface of 304 and is not related to exposure time.(3) At 573 K, the bulk structure of 6063, that is the grain size, has been changed due to recrystallization. This process produces an obvious effect on the bulk outgassing rate of CO and CO 2 ,

Evaluation of the small particle adhesion force on low temperature surface in high vacuum using atomic force microscopy

“…By applying the constant D 0 in Eq. ( 9) as 2.1 × 10 -6 m 2 s −1 16) and the activation energy E D as 96 meV which was estimated from the experiment result, we obtained the surface diffusion length of the water molecule as 1.3 × 10 5 nm for the contact time of 0.37 s at the substrate temperature of 213 K. Using the activation energy of the adsorption time for water molecules on the Al substrate as 1 eV, which was evaluated in the previous report, 33) and the constant of adsorption time as 1 × 10 -13 s, which is used generally, 31) the adsorption time of water molecules at the surface calculated by Eq. ( 8) would be 4 × 10 11 s which is larger than the contact time of 0.37 s. Therefore, the surface diffusion length of water molecules adsorbed on the substrate during the contact was assumed to be large enough to form a capillary between the particle and the substrate.…”