Fabrication of yttria-stabilized-zirconia coatings using electrophoretic deposition: Effects of agglomerate size distribution on particle packing

Yttria-stabilized-zirconia (YSZ) particles with various size distributions have been electrophoretically deposited (EPD) on Fecralloy substrate to investigate the particle size effect on EPD coatings. The deposition rates, as-deposited particle packing densities, green densities and sintered (for 2 h at 1250 °C in air) coating hardnesses are dependent on particle size. The particle packing arrangement in EPD coatings can be affected by further electric field densification (EFD) of the as-deposited coating in which the wet EPD coating is immersed in pure solvent (acetylacetone) with the application of a constant electric field. The effect of EFD was found to be most effective on small particles (<0.5 μm) when they are co-deposited with large particles (>1 μm). The improvements are reflected in increased mechanical hardness of sintered coatings.