Hydroxyethylidene-1,1-diphosphonic acid surface treatment as insulation technology for iron based soft magnetic composites

Abstract

In this study, we employed HEDP surface treatment as an insulation coating technology for the preparation of iron-based soft magnetic composites. The coating layer primarily comprises metal chelate, alongside minor quantities of iron oxides and hydroxides. The influence of treatment time on the microstructure, corrosion resistance and electromagnetic properties of the soft magnetic composites is investigated. The findings indicate a substantial enhancement in the corrosion resistance of iron powder treated with HEDP, and the iron powder subjected to a 90-minute treatment exhibited the most uniform and dense coating, yielding optimal magnetic properties. Notably, the sample's loss after a 90-minute treatment is recorded at 360.6 mW/g, indicating a remarkable reduction of 66.88 % when compared to the untreated sample. This research offers a straightforward and cost-effective approach for the industrial-scale production of soft magnetic composite materials with exceptional magnetic characteristics.