Analytical test on Aluminium buttons

[isaivani]

We use aluminium buttons to make a polyamine. Temperatures are in the range of 60 - 120 deg.C. Recently we've been having problems with slow reaction times and have identified the Al buttons as the cause of the problem. The aluminium button has an oxide layer. We want to have a quick test so that we can tell what the content of the buttons is. However, the oxide layer needs to be removed , before we can do a conclusive test at the operating conditions of the reaction as is in the plant. Any ideas on how to remove the oxide layer and quick test for chking the Al button contents?
Thanks

 

[kenvlach]

Removing the oxide is easy: Dip the aluminum in 20 vol% nitric acid (& rinse).

Not sure what kind of analysis you want. SEM with EDS is convenient compared to chemical analysis.
Maybe
ASTM E34, 'Standard Test Methods for
Chemical Analysis of Aluminum and Aluminum-Base Alloys,' or
ASTM E1251, 'Test Method for Analysis of Aluminum and Aluminum Alloys by Atomic Emission Spectrometry.'

http://www.astm.org

But, these analyses are for metals & metalloids; analysis for oxygen is difficult. Surface oxide can be detected by electrical conductivity (or eddy current on flat surface of at least 1/8").