Fabrication of composite nanoparticles via electrostatic assembly and its application in ceramics preparation

Nanomaterials exhibit properties not seen in large-scale materials; therefore, they have been developed for different applications. Top-down and bottom-up approaches are used to design and fabricate composite materials. Electrostatic assembly (ESA) is a bottom-up approach to material design. In this study, SiO₂‒SiO₂ composite nanoparticles were selected as a model to demonstrate the feasibility of fabricating composite particles via ESA. In addition, researchers have been studying the fabrication of high-density Al₂O₃ (which has a theoretical density of approximately 3.95 g ml^− 1) at moderate temperatures for a long time. In this study, composite particles consisting of small Al₂O₃ particles (low sintering temperature) surrounding large Al₂O₃ particles (high sintering temperature) were fabricated via ESA. The sintered bodies of Al₂O₃ composite particles obtained at 1350 °C for 2 h had a density of approximately 3.0 g cm^− 3, which exceeded that of sintered bodies of only high-temperature-sintered Al₂O₃ (2.8 g cm^− 3).