First, etch the Al foil surface with suitable solutions.

http://www.freepatentsonline.com/5405493.html

First, etch the Al foil surface with suitable solutions.

http://www.freepatentsonline.com/5405493.html

Dear Dr..Hiba Naser,

if you could take a small part of Al foil (e.g. 2x2 cm) where the oily part is present, a direct analysis by FT-IR spectrophotometry with ATR or specular reflectance accessory could provide you with the spectrum and identify (if there is a database) the organic substance (if in common and / or commercial use) in a very brief time.

Best regards, Pierluigi Traverso

Dear Hiba Naser

I think that oxide growth on the foil is the main cause for adhesion failure between the surface and the coating.

Please go through the very interesting article on the following Google link, I hope it contain a bundle of knowledge covering your question.

www.tappi.org › content › enewsletters › eplace

Best regards

The water-break test is the simplest test to find if there are on the surface hydrophobic residues.

https://www.sciencedirect.com/topics/engineering/water-break-test

"Water-Break Test

The water-break test uses running water, allowing it to form a sheet across the surface [32,33]. Breaks in the water indicate the presence of hydrophobic residues. The water break test is a fairly crude test, which is suitable for detecting films of process oils and heavy fingerprints. The test is often used for parts washing and is generally not suitable for precision-cleaning applications. It does not readily detect nonhydrophobic contaminants."

Dear Hiba Naser

As per my previous answer, you can follow the article contents directly from the attached file titled "Adhesion of Aluminum Foil to Coatings – Stick With it" by

Günter Schubert.

Best regards

Thank you Dr. Al'Atia, this article is interesting I've read it since I start trouble shooting the issue. but what I understand that the oxide growth between layers cause a different failures other than adhesion failure such as sticking .. and I didn't notice any sticking in the foil actually.

Mohammed Hussein j. H. Al'Atia Thank you Dr. Al'Atia, this article is interesting I've read it since I start trouble shooting the issue. but what I understand that the oxide growth between layers cause a different failures other than adhesion failure such as sticking .. and I didn't notice any sticking in the foil actually

Dear Hiba Naser,

I agree with Pierluigi Traverso .

dear Osamah Ihsan Ali and Giacomo Bordiga thanks for your suggestion, and yes I did the test and it gives a good results.