Characterisation of oxide and hydroxide layers on technical aluminum materials using XPS

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• 作者：J. Zä ; hr^a ; ^{julia.zaehr@tu-dresden.de} ; S. Oswald^b ; M. Tü ; rpe^c ; H.J. Ullrich^a ; U. Fü ; ssel^a
• 关键词：Al-oxide ; Brazing ; Climate tests ; XPS
• 刊名：Vacuum
• 出版年：2012
• 期刊代码：83_0042207x
• 类别：ph
• 出版时间：14 March, 2012
• 卷：86
• 期：9
• 页码：1216-1219
• 文件大小：456 K

摘要

Aluminum alloys are widely used as technical lightweight materials. For industrial applications, these materials often have to be bonded, e. g. welded or brazed. To get a metallic connection by brazing, the natural oxide layer on Al-materials, which is dense and has a high melting point, has to be eliminated. This layer can be influenced by the temperature and humidity in the surrounding atmosphere. Due to the nm-thickness of the layer, the analysis of its thickness and composition is challenging. An applicable method is X-ray photoelectron spectroscopy (XPS). The present investigation shows the applicability of XPS to estimate the oxide layer thickness as well as to distinguish between Al-hydroxide and Al-oxide phases. Finally, reasons for the differences in brazeability depending on the previous storage conditions are studied. It is shown, that a storage under condensation for 9 days causes an increase of the oxide layer thickness and an aggregation of water inside the pores of the hydroxide layer. This lowers significantly the brazeability of the material.