Nitric acid does not undergo passivation.
Iron, aluminum and concentrated nitric acid will occur passivation reaction, the condition must be at room temperature, heating or low acid concentration will not passivation.
The so-called passivation refers to the formation of a dense oxide protective film on the surface of the metal to prevent the internal metal from continuing to react. So passivation itself is a REDOX reaction; Only at room temperature does not continue to react, under heating conditions, the generated oxide film will react with the acid, and the protection will disappear.