Co-Precipitation on Ni-Zn Ferrite Precursor Powder: Effects of Heat Treatment Conditions and Deagglomeration on the Structure and Magnetic Properties

• Type: Article in International Scientific Journal
• Date: 2012

Authors

Susana M. Olhero (Author) FEUP; Das Soma (Author) Other; Vitor S. Amaral (Author) Other; Tim W. Button (Author) Other; Fernando J. Alves (Author) FEUP; José M.F. Ferreira (Author) Other

Journal

Title: Journal of the European Ceramic Society

Vol. 32 No. 10

Pages: 2469-2476

ISSN: 0955-2219

Publisher: Elsevier

Scientific classification

FOS: Engineering and technology > Materials engineering

CORDIS: Technological sciences > Engineering > Materials engineering

Other information

Abstract (EN): A Ni–Zn ferrite precursor powder was synthesized by co-precipitation upon adding ammonia to an aqueous solution of the precursor iron, nickel, and zinc nitrate salts. The powder was calcined at a range of temperatures (200–1200ºC) and the crystalline phase evolution was assessed by X-ray diffraction coupled with Rietveld refinement. Intermediate phases (NiFe2O4 and Fe2O3) with increasing crystallinity coexisted in the system up to 1000ºC. The required Ni0.8Zn0.2Fe2O4 phase could only be attained at 1200ºC. The magnetic properties measured using a vibrating sample magnetometer revealed high magnetization saturation level (∼59 emu/gm) above 400ºC. The coercivity showed a steady decrease with increasing heat treatment temperature, leading to a change from a hard to soft magnetic state. The BET specific surface area and the SEM morphology were found to be dependent on calcination temperature, atmosphere (air or N2) and on the milling procedure.

Language: English

Type (Professor's evaluation): Scientific