Influence of the Surface-Laver Structure in Outgassing and Photo-Irradiation Effect

表面紫菜结构对放气和光照射效应的影响

• 批准号: 61470060
• 负责人: HOMMA Teiichi
• 金额: $ 4.16万
• 依托单位: Institute of Industrial Science,University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (B)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-61470060/
• 关键词: Aluminum; Surface layer; Outgassing; Photo-Irradiation; Vacuum; 昇温脱離; 超高真空材料

1. SURFACE LAYER STRUCTUREThe surfacw layer structure of aluminum alloys which are main constructional materials of large accelerators and storage rings has been investigated. The following results have been obtained. (1) In case of electrochemical polishing, an initial oxide layer formed on a magnesium-containing aluminum alloy has an amorphous hydroxide, and it dehydrates during vacuum heating. Radial distribution function obtained from electron diffraction revealed the structure being <gamma>-Al_2O_3. (2) Short-circuit diffusion of magnesium through the oxid occured and MgO phase appeared at the top surface at a low temperature of 150゜C as the baking temperature.2. INFLUENCE OF THE SURFACE LAYER STRUCTURE ON OUTGASSINGThermal desorption spectrum was measured to investigate an influence of the surface layer structure on outgassing characteristic and a baking effect. The results obtained are as follows. (1) When the surface polished electrochemically was heated, rapid gas evolution occured due to thermal decomposition of the surface layer. (2) The oxidized surface of a 2.3% aluminum-magnesium alloy may adsorb gases(H_2O,H_2,CO_2) except for CO when exposed to air. (3) A correlation between the surface layer structure and outgassing characteristic has been observed.characteristic has been observed.3. OUTGASSING DURING PHOTO-IRRADIATION AND A ROLE OF THE SURFACE LAYER STRUCTUREA photo-irradiation experiment was undertaken to investigate a mechanism of outgassing and to find an influence of the surface layer structure. The following results were obtained. (1) Outgassing rate depends on the surface which was prepared with different treatments,that is, anodic oxidation,electrochemical polishing, and thermal oxidation (500゜C,10 Torr pure oxygen,1h). Desorption yield normalized by photon number changes in order of the above order. (2) Effect of the surface layer structure and a chemical nature(a degree of hydrate) on outgassing character has been found experimenally.

1.表面层结构研究大型加速器和储存环的主要结构材料铝合金的表面层结构。取得了以下成果。(1)在电化学抛光的情况下，在含镁铝合金上形成的初始氧化层具有无定形氢氧化物，并在真空加热时脱水。电子衍射得到的径向分布函数表明其结构为-lt；γ&gt；-Al_2O_3。(2)当焙烧温度为150゜C时，镁在氧化物中发生短路扩散，在顶部表面出现氧化镁相。测量了表面层结构对热脱附谱的影响，考察了表面层结构对放气特性和焙烧效果的影响。取得的结果如下。(1)电化学抛光表面加热时，由于表面层的热分解，发生了快速析气现象。(2)除CO外，2.3%铝镁合金在空气中的氧化表面可吸附气体(H_2O、H_2、CO_2)。(3)观察到了表面层结构与放气特性之间的关系，并观察到了放气特性。通过光辐照放气和表面层结构的作用实验，研究了放气机理和表面层结构对放气的影响。得到了以下结果。(1)放气率取决于不同处理的表面，即阳极氧化、电化学抛光和热氧化(500゜C，10Torr纯氧，1h)。用光子数归一化的解吸产率按上述顺序变化。(2)实验发现了表面层结构和化学性质(水合物程度)对放气特性的影响。

项目成果

T. Homma: J. Vac. Sci. Technol.,. A5-4. 1686-1687 (1987)

T. Homma：J. Vac。

本間禎一: 真空. 31. (1988)

本间正一：真空 31。（1988）

Teiichi,HOMMA: "A barrier characteristic of aluminum oxide layer in outgassing" J. Vacuum Soc. Japan, "SHI-Ku". 31. (1988)

Teiichi，HOMMA：“排气中氧化铝层的阻隔特性”J. Vacuum Soc。

本間禎一: KEK Report. 87-8. 113-117 (1987)

本间正一：KEK 报告 87-8（1987）。

Teiichi,HOMMA: "Structural characterization of thin films formed on aluminum alloys" J. Vac. Sci. Technol.A5-4 1987. (1686-1687)

Teiichi，HOMMA：“铝合金上形成的薄膜的结构表征”J. Vac。