Inkjet printing of Ce0.8Gd0.2O2 thin films on Ni-5%W flexible substrates

The successful inkjet printing of a cerium gadolinium oxide (Ce0.8Gd0.2O2) precursor solution on highly textured Ni-5%W is reported. A stable ink was synthesised from metal acetates and propionic acid with rheological properties suitable for inkjet printing and also the development of solid-liquid interface comparable with thin film formation by dip coating. Two different drop-on-demand print heads were used for deposition: a 16-nozzle piezoelectric cartridge and a single electromagnetic nozzle. Two different rastering patterns with different droplet sizes and spacing were compared. Thermogravimetry and X-ray diffractometry were used to study the thermal decomposition of the metal oxide precursors and to determine the shortest possible heat treatment of the deposited layers, potentially suitable for continuous large scale production. The results from X-ray diffraction show that the single phase Ce0.8Gd0.2O2 was obtained in all cases, but only piezoelectric inkjet printing with optimised drop overlapping produces a highly textured buffer layer. Optical micrographs and atomic force microscopy also indicate the good quality of deposited films after heat treatment.