Corrosion of metal

Why would a metal corrode more in a lower concentration of nitric acid compared to a higher concentration sulfuric acid? Isn't sulfuric acid suppose to be a stronger acid compared to nitric acid?

• It depends on the electronegativity of the metal relative to $\ce{NO3^-}$. For example, Mg, Mn and Zn all reduce $\ce{H+}$ to $\ce{H2}$. The more electronegative metals Ag however reduces $\ce{NO3^-}$ to NO. $\ce{NO3^-}$ is in it's most oxidized state reasonably possible, and more prone than some other acids to being reduced, thus making it a relatively strong oxidezer. – airhuff Feb 9 '17 at 19:34