Soft Ferrites

The production of soft ferrite starts with weighing, mixing, and milling raw materials. The blended powders are calcined at high temperatures to eliminate volatile impurities and begin forming the ferrite phase. This pre-sintered material is then finely milled in a water slurry. A minor amount of organic binder is mixed in, and the slurry is spray-dried into granules. These granules are placed in molds and pressed into specific shapes. The resulting green body is sintered at elevated temperatures in a controlled atmosphere, creating a dense, uniform structure of soft ferrite. Post-sintering, soft ferrites are machined to exact dimensions and finishes, and may be polished to enhance surface quality.

Ferrites are commonly grouped as “soft” or “hard” depending on their magnetic properties and uses. Soft ferrites, with low coercivity, can readily alter their magnetization, serving as magnetic field conductors, making them perfect for the electronics sector in creating efficient ferrite cores for high-frequency inductors, transformers, antennas, and microwave components. Conversely, hard ferrites, with high coercivity, form ferrite magnets that retain magnetization. The table below offers a detailed comparison of soft ferrite and hard ferrite to enhance your understanding of their distinctions.

MnZn and NiZn ferrites, two prevalent types of soft ferrites, possess unique properties and uses. MnZn ferrites offer greater magnetic permeability, fitting low to medium frequency uses up to 2 MHz, but their lower electrical resistivity increases eddy current losses at high frequencies. In contrast, NiZn ferrites, with reduced magnetic permeability and higher electrical resistivity, excel in high-frequency applications above 2 MHz. NiZn ferrites better minimize eddy current losses and provide superior thermal stability at elevated frequencies compared to MnZn ferrites.