Effect of structural defects on corrosion initiation of TiN nanocrystalline films

•In situ AFM observation is used to study evolution of defects on TiN film in media.•Corrosion initiates at larger pores in the form of detachment of particles nearby.•Pinholes are easily filled in by corrosion products at the beginning of corrosion.•Surface roughness of the TiN film is improved with increasing corrosion time.•Corrosion morphology shows fewer but large pits present on the TiN films.