The Electrophoretic Deposition of Nanopowders Based on Yttrium Oxide for Bulk Ceramics Fabrication

Abstract

In the present work, a study was carried out to investigate the key factors that determine the uniformity, mass, thickness, and density of compacts obtained from nanopowders of solid solutions of yttrium and lanthanum oxides ((LaxY1−x)2O3) with the help of the electrophoretic deposition (EPD). Nanopowders were obtained by laser ablation of a mixture of powders of yttrium oxide and lanthanum oxide in air. The implemented mechanisms of the EPD and factors of stability of alcohol suspensions are analyzed. It has been shown that acetylacetone with a concentration of 1 mg/m2 can be used as a dispersant for stabilization of isopropanol suspensions of the nanoparticles during the EPD. It was shown that the maximum density of dry compacts with a thickness of 2.4 mm reaches 37% of theoretical when EPD is performed in vertical direction from a suspension of nanopowders with addition of acetylacetone.

Electrophoretic Deposition of One- and Two-Layer Compacts of Holmium and Yttrium Oxide Nanopowders for Magneto-Optical Ceramics Fabrication

“…The harvested YLa powders contained weakly agglomerated spherical nanoparticles with a characteristic size of 15-20 nm. The morphology of nanoparticles and their size distribution are shown in [24]. In addition to the nanoparticles, the powder contained spherical particles with a characteristic size of 100-200 nm, formed as a result of the spattering of melted material in the focal spot of the laser radiation, and shapeless particles with a size of 10-100 µm, formed due to splitting of a crust from the target surface.…”

“….+16 mV). Previous experiments on the EPD of nanoparticles from isopropanol suspensions [24] showed the necessity to use a dispersant, because without it, when the electric field was applied, the flocculation process began in the suspension and the entire nanopowder settled to the bottom of the cuvette rather quickly. When acetylacetone, used in this study as a dispersant, is added, the zeta potential of nanoparticles increases significantly (+49.…”

“…On the one hand, suspensions must be stable during the entire EPD process, i.e., the particles should repel each other and not flocculate, and on the other hand, after deposition on the electrode, the particles should form an "ideal" densely packed structure. In the works [23,24], a possibility of sintering optical ceramics based on (La x Y 1−x ) 2 O 3 solid solutions, where lanthanum oxide was used as a sintering aid, and green bodies with a relatively low density (30-40%) made by EPD from isopropyl alcohol suspensions of nanoparticles produced by laser synthesis was shown.…”

Electrophoretic Deposition and Characterization of Er-Doped Bi2O3 Cathode Barrier Coatings on Non-Conductive Ce0.8Sm0.2O1.9 Electrolyte Substrates

“…The amount of acetylacetone added as a dispersant was calculated on the specific surface of the EDB powder, namely in the amount of 5 mg/m 2 . The principles of introducing acetylacetone as a dispersant were described in our recent study [40]. After the addition of acetylacetone (0.15 g/L) to the suspension of EDB in isopropanol with PEI and UST for 125 min, the zeta potential and pH values were +9 mV and 10.5, respectively.…”

Electrophoretic Deposition of One- and Two-Layers Compacts of Holmium and Yttrium Oxide Nanopowders for Magneto-optical Ceramics Fabrication

“…the particles should repel each other and not flocculate, and on the other hand, after deposition on the electrode, the particles should form an "ideal" dense packed structure. In the works [23,24] a possibility of sintering optical ceramics based on (LaxY1−x)2O3 solid solutions, where lanthanum oxide was used as a sintering aid, from green bodies with a relatively low density (30 -40%) made by the EPD from isopropyl alcohol suspensions of nanoparticles produced by laser synthesis was shown.…”