Influence of heat treatment on cobalt ferrite ceramic powders

✍ Scribed by Juliana B. Silva; Walter de Brito; Nelcy D.S. Mohallem

• Publisher: Elsevier Science
• Year: 2004
• Tongue: English
• Weight: 138 KB
• Volume: 112
• Category: Article
• ISSN: 0921-5107
• DOI: 10.1016/j.mseb.2004.05.029

✦ Synopsis

Nanocrystalline CoFe 2 O 4 powders were synthesized using metallic nitrates dispersed in aqueous media precipitated by stoichiometric amount of NH 4 OH. The obtained amorphous powder was washed, dried at 80 8C and heat-treated at various temperatures for 2 h for crystallization of the material. The influence of heat treatment on the texture and morphology of the cobalt ferrite powder was studied. The specific surface area varied from 150 to 1 m 2 g À1 while the average crystallite size varied from 17 to 100 nm with the annealing temperature. The corresponding saturation magnetization value at room temperature varied from 25.9 to 60.3 emu g À1 and the coercivity increases up to 1.5 kOe when the crystallite size reached 94 nm and dropped up to 0.54 kOe with the increase in crystallite size.