Laser Machining of Nickel Oxide–Yttria Stabilized Zirconia Composite for Surface Modification in Solid Oxide Fuel Cells

Abstract

Laser machining of the nickel oxide–yttria-stabilized zirconia (NiO–YSZ) composite in Solid Oxide Fuel Cells (SOFCs) may be an effective approach to enlarge the electrode–electrolyte interface and improve the cell performance. However, laser energy can cause thermal damage to the composite surface during the machined operation. In this work, the microstructure changes and the collateral damage caused by pulsed laser machining on the sintered NiO–YSZ of the state-of-the-art SOFCs were evaluated using complementary analysis techniques. Laser patterns consisting of parallel tracks on sintered NiO–YSZ were processed, varying the laser parameters such as frequency and laser beam energy density. The analyses evidenced a heat-affected zone (HAZ) limited to around 2 µm with microcracking, porosity reduction, and recrystallization. The changes in chemical composition, phase transformation of YSZ and mechanical properties at the machined surface were quite limited.