Carbon Black in black inks attacking aluminum

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.

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.

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.