Industry-oriented Fe-based amorphous soft magnetic composites with SiO2-coated layer by one-pot high-efficient synthesis method

A new one-pot highly efficient synthesis method implemented using an industry-oriented roboticized coating device was designed and developed for obtaining high quality SiO2-coating on the surface of commrercial Fe78Si13B9 (FeSiB) amorphous flaky powder at the room temperature. Hereinto, the conventional instilling method was modified as directly pouring the ultra-diluted precursor by anhydrous ethanol into the reaction mixture, favorable for both simple operation and shortening the total manufacture time to 1.9 h (including the drying time of about 0.7 h). Comparison and analysis on the soft magnetic properties of the FeSiB amorphous powder cores insulated using different precursor concentration within the range of 0 similar to 0.25 ml/g were investigated in detail. SEM, EDS, and FTIR were employed to characterize the core-shell structure of magnetic powders. The increment of pinning sites induced by the raising precursor concentration can cause a reduction in effective permeability, while result in the increases of hysteresis loss and excess loss. The eddy current loss contributes only about 13.5% similar to 18.1% of total core loss for the coated powder cores under the TEOS concentration over 0.09 ml/g, indicating that the corresponding magnetic composites have a good electro-insulating layer. This work offered a referable idea for efficiently coating other inorganic insulations on the magnetic powders within different shapes.