THE GROWTH AND LOCALIZED BREAKDOWN OF THE PASSIVE FILM ON IRON IN 0.05 M NaOH STUDIED IN SITU USING RAMAN MICROSCOPY AND POTENTIODYNAMIC POLARIZATION Michél Karin Nieuwoudt A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy Johannesburg, October 2012