Insulating Technology Control of Soft Magnetic Composites

In this paper, fabrication procedures were adjusted and investigated in soft magnetic composite (SMCs) when the micro-scale iron powder was served as matrix with amorphous silica as the insulating coating layer. The coating situations were alternated by transforming the TEOS (tetraethoxysilane) hydrolysis parameters such as temperature, PH value, and TEOS reagent dosage. It was found that the silica deposited on raw iron particles which is produced by the hydrolysis reaction from the increasing addition of TEOS reagent would make the coating layer too thick. Over-high pH value would has a great negative influence on the silica coating layers, over-high temperature would speed the hydrolysis reaction up, while silica derived from hydrolysis reaction were self-assembled to silica particles and the deposition amounts on iron particles were less. Moreover, the circumstances of insulation coating layer were characterized by introducing low frequency complex dielectric parameters as indirect assessments. The magnetic properties including saturation flux density (Bs), hysteresis loss were investigated. SEM images were presented to directly exhibit the morphology of coated iron particles. The thorough investigation of coated particles’ fabrication procedures greatly facilitates the applications of soft magnetic materials.