The reason for the high corrosion resistance of Al-Zn films is unclear. To relate this behavior to the structure and fabrication we have studied films deposited by dc biased magnetron sputtering onto Fe-Cr substrates. Changes of composition, structure, and electrochemical polarization behavior of resultant films were measured as a function of experimental parameters, including on-axis and off-axis substrate positions. The films, 1.6-4 mum thick, were deposited with a chamber Ar pressure of 10 mTorr (1.33 Pa), substrate temperature of 22-90-degrees-C, and substrate bias of -60 to -380 V. Transmission electron photomicrographs of thin alloy films exhibited polycrystalline structure comprising one or two phases depending on film composition. Lower bias (-60 V) tends to produce two phases. Reflection high-energy electron diffraction photomicrographs also presented polycrystal ring patterns. Energy-dispersive x-ray spectroscopy analysis of as-deposited films revealed that Al vapor flux was more likely than Zn to go axially. The enrichment of Al in the on-axis films increased dramatically with increasing substrate bias. The bias effect was small in off-axis films. The enrichment of Al in films also varied with target composition. Film surface morphology and cross sections were examined with scanning electron microscopy : zinc-rich targets and lower biases led to porous structures. Higher biases (-380 V) and Al-rich targets led to dense columnar structures. Transmission electron microscopy images showed a reduction of average grain size with increasing substrate bias. The deposited thin films presented active-passive transitions in potentiodynamic tests. Step passivity was observed on porous films but not on dense films. Alloy films had higher corrosion resistance than corresponding bulk material as a result of reduced grain size and better chemical uniformity, which enhances the films’ passive behavior.