Raman mapping, scanning Kelvin probe force microscopy (SKPFM), and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) were combined to investigate oxidized zirconium alloys. Raman provided spatially resolved phase composition and relative stress state. When coupled with SKPFM, phase composition was correlated to Volta potentials differences. The potential of tetragonal zirconia was lower than the metal zirconium, making the tetragonal phase favorable for reaction with diffusing species, thus hindering further oxidation of the relatively cathodic metal. This provides new insight to the theory of the tetragonal phase being an oxidation barrier.