Manufacturing and properties characterization of Ti patterned coatings for water electrolyzers by CSAM

• The masked CSAM process efficiently produces BPPs with customized flow-fields. • CSAM Ti coatings showed a stable oxide film at typical PEM electrolyzer operation potentials. • Using irregular Ti powder contributes to cost-effective manufacturing of BPPs. This work investigates the microstructure and manufacturing control of the masked Cold Spray Additive Manufacturing (CSAM) strategy for producing of new bipolar plates (BPPs) for Proton Exchange Membrane (PEM) electrolyzers, using low-cost, lightweight, and machinable materials. CSAM is a solid-state process capable of fabricating 3D patterned parts based on a bottom-up approach using masks with a desired pattern. This study focuses on the dimensional and microstructural characteristics of pin fins fabricated with spherical (Ti-S) and irregular (Ti-I) Ti powders using the masked CSAM technology. Additionally, the performance of both Ti parts for its application in PEM electrolyzers was evaluated in terms of corrosion resistance and interfacial contact resistance (ICR). The results demonstrated that the masked CSAM technology allowed precise control and customization of the dimensions of the 3D-printed pin fins, obtaining porosity values of 6 ± 1 % for Ti-S and 4 ± 1 % for Ti-I. The evaluation of the corrosion resistance of the CSAM Ti patterned parts showed that for both Ti-S and Ti-I powders a stable oxide film at the typical operation potential (1.8 V vs Ag/AgCl) of a PEM water electrolyzer was formed without signs of pitting corrosion. Finally, at a compaction pressure of 150 N/cm 2 ICR values of 42 ± 19, 40 ± 13, and 24 ± 7 mΩ·cm 2 were obtained for Ti-I, Ti-S, and standard Ti Bulk, respectively. The results suggest than the masked CSAM technology shows great potential for the fabrication of Ti BPPs.