|06-230||Massimo Rosa||Rosa, M.(Technical Universiy of Denmark); Xu, Y.(Technical Universiy of Denmark); Zielke, P.(Technical Universiy of Denmark); Esposito, V.(Technical University of Denmark);||
Continuous hydrothermal synthesis with supercritical water (scWHS) is a powerful technique for producing well-dispersed suspensions of nanoparticles and has been recently scaled-up to the industrial level. In particular, scWHS has been studied extensively for the synthesis of metal oxides, such as yttria stabilized zirconia (YSZ) and NiO. Both YSZ and NiO are well-known materials with application in energy conversion devices like oxygen transport membranes, alkaline electrolysers, and solid oxide fuel cells. Using nanoparticles, is particularly attractive for fabricating of energy conversion devices because it allows achieving finer microstructures with larger interfaces. Moreover, decreasing the particle size results in lower sintering temperatures at the consolidation step. In addition, inkjet printing has been demonstrated as a viable method for the fabrication of complex patterns by depositing small volumes (10-9-10-12 liters) of particle-loaded inks. Therefore, combining inkjet and nanoparticles represents an interesting route for printing structures with high spatial resolution. We here propose a novel approach for printing metal oxide nanoparticles using scWHS-based inks. These suspensions are converted into inks by modifying the fluid properties on the basis of the printability parameter, Z. This is defined as the inverse of the Ohnesorge number and must assume values 1 < Z < 10. This combined strategy allows avoiding critical steps as milling and dispersing of dried powders. After formulating the inks, they are printed and the sintering behaviour of the resulting patterns is investigated. The printed nano-materials have interesting properties: nanoparticles show a remarkable self-leveling effect on rough surfaces and low sintering temperature, as densification is reached at 1200 °C for YSZ.