
plating, anodizing, & finishing Q&As since 1989
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Carbon Black in black inks attacking aluminum
October 3, 2012
Q. Is there any evidence to support carbon black in inks can attack aluminum. The application is ink applied to hot stamping foil.
Brian Hill- Lexington, North Carolina, USA
A. Carbon Black per se, NO, but what is the pH of the solution. Any pH ± 1 away from 7.0 will attack aluminum, particularly with heat.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

A. I do not know about carbon, but I do know that a common pencil marking on Al in a coastal area will slowly eat through it.
James Watts- Navarre, Florida
A. I would check the MSDS of the particular ink you are using. If there are certain solvents in your ink, that could be a cause of corrosion.
Aluminum in itself, is very susceptible to corrosion, hence the need for coatings.
Without seeing a picture of your situation, I'm also wondering if the "corrosion" you are noting is the ink actually preventing that natural oxidation of aluminum that will occur around the inked areas.

Marc Green
anodizer - Boise, Idaho
