Laser processing of Crofer22APU and 3YSZ: an interlocking approach for improved interfaces with glass-based seals in solid oxide electrolysers

Since glass-to-metal joining reliability over a pressure difference is key in preventing gas mixing and consequent stack failure, enhanced surface-modified interconnect-sealant interfaces represent a specific focus in solid oxide electrolysers integration. This study successfully applied laser surface patterning to Crofer22APU and 3 mol% yttria-stabilized zirconia (3YSZ) substrates, enabling reproducible and controlled texturing. Mechanical testing confirmed that such patterning considerably improved joint strength, with no measurable adhesion in untreated samples and peak mechanical resistance reaching approximately 34 MPa in laser-treated Crofer/Crofer and Crofer/3YSZ configurations. A new composite glass-based paste was developed using a 3YSZ-based approach, showing the proper balance of an adequate design of the interconnect roughness while avoiding significant defects at the glass-to-metal interface. This formulation incorporated 10 wt% 3YSZ into the glass matrix, significantly increasing the high-temperature viscosity (from 104.8 to 106.1 Poise) and enhancing processing stability and application performance. The composite paste exhibited excellent rheological properties, with viscosities in the 10–100 Pa s range and 80 % recovery after high shear stress (200 s− 1), making it highly suitable for robocasting. Importantly, the robocasted glass structures with laser-patterned surfaces withstood pressure differentials of up to 4 bar, demonstrating robust sealing performance. Leak-tightness was further validated through nitrogen pressure difference tests up to 4 bars without any detectable leakage.