Composite dispersants for the preparation of monodisperse spherical alumina with uniform particle size

Spherical α-alumina powder has been widely used in advanced alumina ceramics manufacturing due to its excellent sphericity, uniform particle size distribution and good dispersion. However, the small size and fast growth rate of α-alumina precursor particles lead to strong agglomeration during grain growth, making it difficult to obtain uniformly dispersed α-alumina particles with good sphericity. In this study, polyethylene glycol 2000 (PEG2000) and poly (ammonium acrylate) (PAA-NH 4 ) were used as composite dispersants to decrease agglomeration during the preparation of alumina precursors. When the contents of PEG2000 and PAA-NH 4 were 0.5 g L −1 and 0.06 g L −1 (S4), respectively, uniformly dispersed alumina precursor particles with good sphericity and a particle size of about 506 nm were obtained, and the morphology remained stable after calcination. After molding and sintering the calcined powders, alumina ceramics with superior mechanical properties were produced. Compared to commercial α-alumina ceramics, flexural strength is increased by approximately 28.9 %, while fracture toughness is increased by approximately 29.2 %. This study offers a new foundation for the development of high-performance alumina powders and ceramics, supporting their engineering applications.