3D microextrusion of eco-friendly water based cer-cer composite pastes for hydrogen separation

Ceramic membranes operating at high-temperatures are a key-technology for hydrogen separation processes. Cercer composites based on BaCe0.65Zr0.20Y0.15O3-delta-Gd0.2Ce0.8O2-delta have gained increasing attention as asymmetric membranes for H-2 purification, for their high proton-electron conductivity, 100% selectivity, temperature and chemical stability, and intrinsic lower costs compared with the Pd-based technologies. Here, BCZY-GDC composite parts were successfully fabricated for the first time by microextrusion. Water-based pastes with different solid loadings and suitable rheological properties were formulated and printed in single or multilayer structures without nozzle clogging. After deposition, the samples were osmotically dried in concentrated PEG solutions in order to obtain cracks-free green bodies. The further process optimization allowed the production of planar BCZY-GDC ceramics to be potentially applied in asymmetric membrane structures. The mechanical properties of the as-obtained single and multilayer structures as well as of the interface between filaments were assessed through different nanoindentation techniques.