Influence of SSA and Particle Size Distribution of Iron Oxide on Magnetic Properties of Mn-Zn Ferrite

摘要

In this work, Fe2O3 powders with different industrial specific surface area (SSA) made by different processes including spray roasting and fluidized-bed process have been prepared. The SSA, particle size distribution, sintering reactivity, solid state reaction as well as magnetic properties of MnZn ferrite for iron oxides are comprehensively investigated. The results show that the primary particles size distribution of iron oxides made by the fluidized-bed process are sharp and less aggregated than that by the spray roasting process, which results in low temperature formation of ZnFe2O4. The primary particles of the fluidized-bed Fe2O3 is around 0.2~0.3μm, which contributes to the highest green density and the highest sintered density without abnormal grain growth. The sintered parts of iron oxides processed by the spray roasting process trigger the grain growth from 95% theoretical density, as well as wet milled SB-Fe2O3 of China Steel Corporation (CSC). However, iron oxides by the fluidized-bed process sustain 98% theoretical density without abnormal grain growth due to the tight particle size distribution with well-controlled particle sizes smaller than 44μm. High SSA of Fe2O3 shows high spinel formation with expansion and the lowest peak temperature of expansion. Iron oxides with SSA of 4~4.5m2 /g reveal the lower hysteresis loss (Ph) and the initial permeability enhances with the increase of SSA for low loss MnZn ferrites.