ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Nanometer-sized spherical hematite single crystals were prepared by heating the precipitate which was synthesized from Fe(OH)(CH3COO)2 and NaOH in alkaline ethanol-water solutions without the deliberate addition of surfactants or adsorbing ligands. Hematite nanocrystals (5–10 nm in diameter) and ferrihydrite (〈5 nm) were obtained from the mixture of H2O/EtOH (Rs) = 100 ml/100 ml as a initial medium, whereas goethite, hematite (20–40 nm), and ferrihydrite were precipitated at Rs = 200/0. Adsorbing ligands such as acetoxy groups and ethanol on particles retarded the hematite growth and goethite formation. TEM observation of the particles prepared at Rs = 100/100 with heat treatment at 400°C for 2 hours showed them consisting of single spherical hematite crystals 22 nm in mean diameter with narrow size distribution. Various individual effects were investigated for their contributions to crystal structure and size of precipitates; they included NaOH to Fe(OH)(CH3COO)2 ratio, solvent, dropping rate of alkaline solution, and aging time.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1004710810785
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