Influence of additive particle content and sintering temperature on the sinterability of electrostatically assembled alumina–alumina composite particles

In this study, bimodal alumina (Al 2 O 3 ) particles with average sizes of 830 nm and 140 nm were used, and an electrostatic assembly method was employed to control the formation of composite particles with varying contents of finer additive particles (140 nm), allowing the investigation of their effect on a pressureless sintering process. A homogeneous distribution of additive particles on the larger alumina core particles (830 nm) was achieved by varying the additive particle content from 12 to 40 vol%. The sinterability of the electrostatically assembled Al 2 O 3 –Al 2 O 3 composite particles was then evaluated by sintering them at temperatures from 1300 to 1450 °C with a holding time of 5 h. The results indicated that the homogeneous distribution of the additive particles in the electrostatically assembled Al 2 O 3 –Al 2 O 3 composite particles led to improved powder packing density and enhanced sinterability. This enabled the fabrication of denser sintered artifacts at lower sintering temperatures. These findings demonstrate that particle design using electrostatic assembly can promote a more efficient sintering process and reduce energy consumption in the fabrication of ceramic materials using powder metallurgy.