Fabricating an effective calcium zirconate layer over the calcia grains via binder-jet 3D-printing for improving the properties of calcia ceramic cores

To improve the formability and properties of calcia (CaO) based ceramic core, the binder-jet 3D-printing was performed to fabricate porous CaO/caicium zirconate (CaZrO3) ceramic core composites with two nanozirconia addition methods. The effects of the nanozirconia addition method and additive amount on the properties of the 3D-printed CaO/CaZrO3 bodies were investigated. The dimensional accuracy, surface roughness, relative density, bending strength, and hydration resistance of CaO/CaZrO3 bodies printed with a nanozirconia suspension binder for deposition in the CaO powder layer were better than those of CaO/CaZrO3 bodies printed in the traditional manner of directly mixing nanozirconia in the CaO powder. Application of the nanozirconia suspension uniformly capped nanozirconia particles on the surfaces of the CaO particles and filled the pores of the CaO powder layer, which afforded denser and more uniform green bodies. After sintering at 1500 °C, the ZrO2 formed thicker and denser CaZrO3 layers with the CaO over the CaO grain surfaces, which improved the strength and hydration resistance of the sintered CaO/CaZrO3 ceramic core bodies, and certainly reduced their collapsibility.