Particulate dispersion and freeform fabrication of BaTiO3 thick films via direct inkjet printing

Abstract

A piezoelectric drop-on-demand inkjet printer was used to print BaTiO3-Ni functionally graded thick films onto porous substrates of computer-defined patterns without the need of prior mold tooling and the use of masks. The inkjet deposits were built up from a sequential delivery of ink droplets expelled from the print-head orifice with a precise location-registration capability upon multiple printings. A uniform dispersion of the particle-filled liquid inks was a prerequisite for a successful printing, and an addition of propylene glycol facilitated the nanoparticles dispersion in evaporative ethanol-isopropanol solvents. Typical line width of the inkjet-printed patterns was as narrow as 200 mu m, and a maximum film thickness attainable exceeded 20 mu m. A uniform concentration gradient of the dissimilar phases was evident along the thickness direction of the printed functional films.