Synthesis of nickel ferrite nanoparticles by sol-gel method

• Published in: Materials research bulletin Vol. 36; no. 7; pp. 1369 - 1377
• Main Authors: Chen, Dong-Hwang, He, Xin-Rong
• Format: Journal Article
• Language: English
• Published: London Elsevier Ltd 01.05.2001; Amsterdam Elsevier Science
• Subjects: Chemistry; Colloidal state and disperse state; Cross-disciplinary physics: materials science; rheology; Disperse systems; Exact sciences and technology; General and physical chemistry; Materials science; Nanoscale materials and structures: fabrication and characterization; Physics; Powders; Heat treatment; Iron oxide; Magnetization; Nanoparticle; Crystallization; Ultrafine particle; Experimental study; Powder; Inorganic compound; Calcining; Characterization; Ferrites spinels; Transition metal compounds; Sol gel process; Chemical preparation; Acrylic acid polymer; Chelating agent; Nanostructured materials; Nickel oxide; Magnetic properties
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/S0025-5408(01)00620-1

NiFe 2O 4 nanoparticles were prepared by the sol-gel method using polyacrylic acid (PAA) as a chelating agent. It was shown that pure spinel NiFe 2O 4 nanoparticles with a diameter of 5∼30 nm and a specific surface area of 20.0∼55.2 m 2/g could be produced by calcining the gel precursors with various molar ratios of PAA to total metal ions (0.5∼2.0) in air at 300°C for 2h. As the molar ratio of PAA to total metal ions increased, particle sizes decreased but the crystallinity increased, revealing PAA not only worked as a chelating agent to disperse the cations homogeneously but also contributed its combustion heat to increase the crystallinity of NiFe 2O 4 nanoparticles. Moreover, the magnetic analysis showed the resultant NiFe 2O 4 nanoparticles might be superparamagnetic. Their saturation magnetization (0.19 emu/mol at 298 K) was slightly lower than that for bulk materials due to small size and increased slightly with decreasing the temperature below 360 K