チタン材料における水のガス放出低減に関する研究

摘要

チタン材料の水のガス放出特性を低減させるために，①表rn面のさらなる平滑化のために前処理としてバフ研磨と②強固rnな表面酸化層の形成のために改良した精密化学研磨処理を開rn発し，表面形態，表面層組成そして水の昇温脱離特性を調べrnた．その結果，表面平滑化処理により，表面粗さが約2/3rnに低減し，酸化処理により表面付近の酸化度合いが高く，そrnして酸化膜厚も厚くなることがわかった．従来の精密化学研rn磨処理したチタンと比較し，バフ研磨と表面酸化を促進したrn精密化学研磨処理したチタンの水の昇温脱離量は，約70%rnに低減できることがわかった．%This paper addresses the development of the surface finishing for a titanium material and the study for the reduction of outgassing property of adsorbed water (H_2O) molecules. Developed surface finishing is composed of the buffing for the reduction of the surface roughness and improved chemical polishing for the thick surface oxide layer compared with the chemical polishing so far. The surface roughness of the surface finished titanium material is reduced 35% and the thickness of the surface oxide layer increases by 30%. The total amount of thermal desorbed H_2O gas for the new surface finished titanium is reduced 30%. It is considered that the origin for the decrease of the amount of desorption H_2O gas is the reduction of the adsorption sites due to the decrease of the surface roughness and the reduction of adsorption energy of H_2O gas due to the strong surface oxidation for a titanium material.