Direct Writing of Dielectric Ceramics and Base Metal Electrodes

Three-dimensional structures were assembled by direct writing of colloidal gel-based inks of electro-ceramic and metal electrode compositions. The ternary mixtures of BaTiO3, BaZrO3, and SrTiO3 were explored via an active mixing nozzle print strategy that allowed for rapid screening of complex oxide ceramics. In a second experiment, Ni and BaTiO3 inks were developed from commercially available powders in the form of concentrated, aqueous colloidal gels having shear thinning with yield stress rheology. The different surface chemistry of Ni and BaTiO3 was accommodated by adsorbing a bi-layer of oppositely charged polyelectrolytes on the BaTiO3 particles. Alternating layers of metal and ceramic were printed to build a multilayer structure. The multilayer Ni–BaTiO3 structures were sintered in a reducing atmosphere and the capacitance was measured. These two examples illustrate the use of discrete or graded deposition capabilities of direct writing.