The effect of B2O3 addition to the microstructure and magnetic properties of Ni0.4Zn0.6Fe2O4 ferrite

Abstract

The effects of 0.01 and 0.1 mol B2O3 addition to the microstructure and magnetic properties of a Ni-Zn ferrite composition expressed by a molecular formula of Ni0.4Zn0.6Fe2O4 were investigated. The toroid-shaped samples prepared by pressing the milled raw materials used in the preparation of the composition were sintered in the range of 1000-1300 degrees C. The addition of 0.01 mol B2O3 increased the grain growth and densification giving rise to reduced intergranular and intragranular porosity due to liquid-phase sintering. The sintered toroid sample at 1300 degrees C gave the optimum magnetic properties of B-r = 170 mT, H-c = 0.025 kA/m and a high initial permeability value of mu(i) = 4000. The increment of the B2O3 content to 0.1 mol resulted in a pronounced grain growth and also gave rise to large porosity due to the evaporation of B2O3 at higher sintering temperatures. Hence, it resulted in an air-gap effect in the hysteresis curves of these samples. (C) 2007 Elsevier B.V. All rights reserved.