Thermal desorption of CO and H2from degassed 304 and 347 stainless steel
作者:
S. Rezaie‐Serej,
R. A. Outlaw,
期刊:
Journal of Vacuum Science&Technology A: Vacuum, Surfaces, and Films
(AIP Available online 1994)
卷期:
Volume 12,
issue 5
页码: 2814-2819
ISSN:0734-2101
年代: 1994
DOI:10.1116/1.578949
出版商: American Vacuum Society
关键词: STAINLESS STEEL−304;STAINLESS STEEL−347;SORPTIVE PROPERTIES;CARBON MONOXIDE;HYDROGEN MOLECULES;TDS;DEGASSING;AES;VACUUM SYSTEMS;TEMPERATURE DEPENDENCE;TEMPERATURE RANGE 0400−1000 K;steels
数据来源: AIP
摘要:
Thermal desorption spectroscopy (TDS), along with Auger electron spectroscopy, was used to study the desorption of H2and CO from baked 304 and 347 stainless‐steel samples exposed only to residual gases. Both 347 and 304 samples gave identical TDS spectra. The spectra for CO contained a sharp leading peak centered in the temperature range 410–440 °C and an exponentially increasing part for temperatures higher than 500 °C, with a small peak around 600 °C appearing as a shoulder. The leading peak followed a second‐order desorption behavior with an activation energy of 28±2 kcal/mol, suggesting that the rate‐limiting step for this peak is most likely a surface reaction that produces the CO molecules in the surface layer. The amount of desorbed CO corresponding to this peak was ∼0.5×1014molecules/cm2. The exponentially rising part of the CO spectrum appeared to originate from a bulk diffusion process. The TDS spectrum for H2consisted of a main peak centered also in the temperature range 410–440 °C, with two small peaks appearing as shoulders at ∼500 and 650 °C. The main peak in this case also displayed a second‐order behavior with an activation energy of 14±2 kcal/mol. The amount of desorbed H2, ∼1.9×1015molecules/cm2, appeared to be independent of the concentration of hydrogen in the bulk, indicating that the majority of the desorbed H2originated from the surface layer.
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