Presentation Information
[2C04]Evaluation of the Chemical bonding State of Ti Alloy Surfaces in a High-Temperature Vacuum Atmosphere Using XPS
*Naoki Muraya1, Makoto Okano1, Yasuteru Nawafune1, Rie Wakimoto1 (1. JEOL Ltd (Japan))
Ti alloys, which are commonly used as getter materials, can exhibit NEG characteristic by heating activation, and reports exist on their surface oxidation states and evacuating characteristic at temperatures below 400°C . However, the oxidation state of Ti alloys at temperatures above 400°C—where improved evacuating characteristic is expected—is not yet fully understood. Therefore, in this study, we investigated changes in the surface oxidation state by acquiring and analyzing XPS spectra of naturally oxidized Ti alloys while heating the samples in an ultra-high vacuum at temperatures ranging from 400°C to 600°C.The experimental results showed that heating at 400°C caused the TiO2 on the sample surface to be reduced to Ti2O3 and TiO, while TiC was formed at the same time; however, no significant changes were observed after about 2 hours, and the final TiC ratio was about 60%. At 500°C, TiC decreased and metallic Ti increased; after 3 hours, ratio of metallic Ti was about 70%. Furthermore, at 600°C, the TiC disappeared in about 20 minutes, resulting in a composition consisting almost entirely of metallic Ti.
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