Titanium-based bipolar plates and Porous Transport Layers (PTLs) currently dominate the cost of Proton Exchange Membrane Water Electrolysis (PEMWE) stacks. Replacing titanium with steel for these components would significantly enhance the cost-efficiency of PEMWE. How-ever, application of stainless-steel components in PEMWE requires functional protective coat-ings, to avoid dissolution of cations (i.e., iron leaching) and to avoid an increase in contact resistance in the locally acidic aqueous environment. This thesis investigates the replacement of expensive titanium components in PEMWE with cost-effective stainless-steel alternatives and is part of the ANR/FNS Franco-Swiss project PROTIS (Films minces d’oxyde de titane sous-stoechiométrique pour la protection de couches de transport poreuses dans les électro-lyseurs PEM).