The effects of alloying elements on the microstructure and magnetic properties of co-precipitated ferrite

Abstract

Soft ferrites of composition Ni_0.96-xZn_xFe_2.04O₄ (x = 0, 0.24, 0.48, 0.72, 0.96) were prepared by co-precipitaton reaction of metal sulfates of Ni²⁺, Zn²⁺ and Fe²⁺ with NH₄OH. The precipitates were filtered, dried at 300°C for 2 hours, and then calcined at 900°C for 5 hours. The calcined powders were pressed in a toroid mold measuring 25 mm o.d., 10 mm i.d. and 3 mm thick at a pressure of 17 tonnes for 1 min. The green bodies were sintered in air for 2 hours at 1100°C. The microstructures of the dried precipitates, calcined (green body) and sintered ferrites were examined using a JSM - 35 JEOL scanning electron microscope (SEM). The compounds formed were analyzed using Cu K-α radiation of a Shimatzu x-ray diffractometer (XRD). The magnetic properties such as permeability and resistivity were measured using the equipment available at the Philippine Nuclear Research Institute (PNRI).