Sintering of Bimodally Distributed Alumina Powders

The densification of alumina powders prepared to have a bi‐modal particle‐size distribution with a coarse‐to‐fine particle‐size ratio of ≊ 10 can be predicted to a first approximation if the densification of the fine and coarse powders is known. Deviations from model prediction were attributed to compositional heterogeneity. Microstructural observations of bimodal powders show that only the fine powder undergoes grain growth. Thus, the grain‐size distribution becomes more uniform than the initial particle‐size distribution.