Formation of Bulk Alumina Ceramics by Electrophoretic Deposition from Nanoparticle Suspensions

High-density ceramics are prepared via electrophoretic deposition (EPD) from suspensions of alumina-based nanopowders. Al2O3-based nanopowders are obtained through the electrical explosion of wires (EEW) using wire made of an Al–Mg alloy with a magnesium content of 1.3 wt %. Stable nonaqueous suspensions for EPD are prepared using slightly aggregated spherical Al2O3 nanoparticles with a specific surface area of 40 m2/g. With EPD and sintering at 1650°С, it is possible to prepare high-density ceramics with a density of 3.93 g/cm3 (98.6% of the theoretical value) and a microhardness of 17.7 ± 0.5 GPa. Using a nanopowder based on alumina prepared from the Al–Mg alloy contributes to a substantial improvement in the sinterability of ceramics, due to the formation of MgAl2O4 spinel at a content of ≈2.5 wt %, which allows the density and microhardness of ceramic samples to be raised.