For the purpose of investigating the outgassing characteristics of titanium, outgassing measurements by the conductance-modulation method for pure titanium and titanium alloy have been made. The surfaces of the chambers were treated with oxidation at 200°C and 450°C in an argon plus oxygen atmosphere after chemical polishing or mechanochemical buffing. The lowest outgassing rate of 5 × 10-9 Pa m3 s-1 m-2 after 50 hr pumping was measured on a pure titanium chamber by oxidation treatment at 200°C. Surface analyses such as TEM were also done on test samples treated in the same conditions as the chambers. Oxidation treatment at 200°C is effective to obtain a low outgassing surface for titanium because of its thin and amorphous oxide film, which was observed by these surface analyses.
