Morphological Changes During Synthesis of Haematite Nanoparticles

Haematite particles were synthesized by Herbert Giesche from NYSCC at Alfred University, NY by aging aqueous FeCl3 or Fe(NO3)3 solutions at 100 degrees C. The different reaction conditions created particles of aspect ratios between 1 (spherical) and 8 (elongated and agglomerated). Their fractal aggregation behavior as well as their morphological evolution characterized using Triple-S.

In Figure 1, the slopes of different curves provide a measure of the fractal dimension of agglomerates formed at different times. It is observed that initially there is no agglomeration and after 12 hours, the agglomeration is significant.

Figure 1 - Intensity of Light Scattered by Particles vs Scattering Wave Vector (q) for Vertically Polarized Incident Light

It is observed from Figure 2, that during the process, the particles have agglomerated and there are more agglomerates with aspect ratios of 8.

Figure 2 - Size and Aspect Ratio of Particles and Agglomerates at the Start and End of the Process (a) 30 minutes after the process began (b) 38 hours, 23 minutes after the process began