Hydrolytic synthesis of titanium oxide insulation layer and its effect on powder core

Abstract

Optimizing insulation technique plays a vital role in developing high performance magnetic powder core. Uniform dense titanium dioxide insulation layer was successfully coated on atomized Fe-Si-Al powder through hydrolysis of tetrabutyl titanate and the effect of water content on insulation quality was systematically investigated. The influences of titanium oxide insulation layer on electromagnetic properties of corresponding powder cores were also discussed. The results show that when the mass of water is increased from 10% to 40% of Fe-Si-Al powder, the insulation layer on particle surface first grows thicker and then becomes loose. High water content favors quick hydrolysis and condensation, while too large volumes of water leads to excessively high hydrolysis rate, which is adverse to the uniform growth and crystallization of titanium dioxide insulation layer. It is proven that uniform and dense insulation layer would contribute to the increase of resistivity under the premise of high density of powder core, which is conducive to the suppression of eddy current and frequency stability of permeability. When the mass of water is 20% of Fe-Si-Al powder, the prepared corresponding powder core has the optimal overall performance, the permeability is as high as 82, the resistivity is up to 1022.35 kΩ·cm and the core loss is as low as 77.63 mW/cm3 (at 100 kHz and 50 mT).

Keywords

• titanium dioxide
• insulation
• fe-si-al
• magnetic powder core
• high resistivity
• high permeability