IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Vacuum Science & Technology Monday Sessions
       Session VST-MoP

Paper VST-MoP10
Outgassing Rate of Newly Titanium Alloy Material

Monday, October 29, 2001, 5:30 pm, Room 134/135

Session: Developments in Vacuum Technology Poster Session
Presenter: H. Kurisu, Yamaguchi University, Japan
Authors: H. Kurisu, Yamaguchi University, Japan
M. Hesaka, Shinko Industrials Co., Japan
T. Muranaka, Yamaguchi University, Japan
S. Yamamoto, Yamaguchi University, Japan
M. Matsuura, Yamaguchi University, Japan
Correspondent: Click to Email
A low outgassing rate material is required to make an XHV system. Titanium is a new candidate material for use in UHV and XHV. Recently vacuum characteristics of titanium materials were investigated and then it was clarified that the outgassing rate of small samples of chemically polished titanium is smaller by a factor of about 1/3 than that of electropolished stainless steel. (M. Minato and Y. Itoh, 1995) In the present work we pay attention to new titanium alloy material (KOBE STEEL,LTD KS100). In this material very flat surface can be obtained by a polishing and the hardness is larger by a factor about 2 than a titanium. We present outgassing property of the polished new titanium alloy in this paper. To measure the out gassing rate of small samples, we prepared the apparatus employing the orifice method with the orifice conductance is about 2.5x10@super -3@m@super 3@/sec (RT, air). In the vacuum system, the vacuum chamber was made of new titanium alloy and the pumping system consists of two turbo molecular pumps. The measurement limit of the outgassing rate is obtained to be 1.6x10@super -11@Pam/sec, when the sample with 160x10@super 3@m@super 2@ area is used, because the pressures of both upper and lower chambers are reached 1x10@super -8@Pa. We prepared the plate samples of polished new titanium alloy materials with the surface roughness of about 1nm. One set of samples consisted of 180 plates with a size of 20x20x1mm (sample area is about 160x10@super 3@m@super 2@). After rough pumping down, samples were kept at 493K and the chamber kept 453K for 48h and then cooled down to room temperature in 48h. Finally out gassing rate was measured. The outgassing rate of the new titanium alloy samples is obtained to be 1.6x10@super -11@Pam/sec, this value is smaller of the order than that of the stainless steel samples under the same measurement condition. On the conference, we will discuss the out gassing property of new titanium alloy materials in details.