Synthesis of monodisperse Al-substituted hematite particles from highly condensed metal hydroxide gels

Monodispersed aluminum-substituted hematite particles were synthesized from concentrated mixed solutions of FeCl3 and AlCl3 using the gel-sol process. With increasing aluminum content (Ay(Fe + Al)) in the starting solutions, hematite particles became more and more elongated. The product particles ex hibited ellipsoidal, rod- and peanut-like shapes, depending on Al concentra tion. Higher Al content (> 20 mol%) in the system greatly suppressed the fo rmation of hematite, Atomic emission spectrometry analysis and lattice para meter measurement confirmed the substitution of Al in hematite particles, ( C) 2000 Academic Press.