What makes an acid more corrosive?

[tonyhu]

I heard that concentration did not matter?

[Jason Wu 1E]

An acid is more corrosive when the pKa is lower (or Ka is higher) or is a strong acid. Corrosion happens when a lewis acid gains electron pairs from metal atoms. This makes the metal atoms positively charged, in order to counteract that the metal cation will be oxidized with surrounding oxygen and undergo a chemical reaction as it corrodes.

[Rohit Srinivas 2D]

I believe the reason concentration doesn't matter is because when the concentration is very high there won't be enough water to be protonated and participate in the reaction, at a dilute concentration there will be enough water to do so. Also both bases and acids are corrosive, not just acids.