With current state-of-the-art corrosion resistant coatings being far from optimized, it is of great interest to further investigate the fundamental mechanisms and underlying driving forces that dominate the degradative process. Particularly saline environments represent a technological frontier, where high-performance components suffer accelerated breakdown through a localized corrosion mechanism called¬¬ pitting. Porosities, macroparticles, and the overall columnar growth morphology of physical vapor deposited coatings makes them particularly susceptible to inward-diffusion of corrosive media. Here, especially chloride ions play a key-role allowing for an accelerated attack at the coating substrate interface. In a first step, this study provides a systematic approach on highlighting preferred diffusion pathways of corrosive NaCl-rich media of Al0.7Cr0.3N-based PVD thin films deposited on low alloy steel. Through an array of high-resolution techniques, such as TEM, ToF-SIMS, APT and t-EBSD, we intend to break down the possible diffusion paths from a micrometer to a nanometer scale, providing newest insights on the corrosion process. In a second step, this study showcases a doping strategy, as well as thermal treatment as viable approaches for improving the corrosion behavior of the previously discussed AlCrN system. In order to investigate the beneficial effects of the dopant, a series of Al0.7Cr0.3-yXyN coatings were deposited with varying alloying contents. Electrochemical tests of the as-deposited, as well as thermally treaded coatings were conducted using a three-electrode cell set up, whereupon extrapolations of Tafel-plots were used to evaluate the corrosion resistance.