The phosphating effect on the properties of FeSiCr alloy powder

The surface passivation is an effective technique to improve the magnetic properties of iron-based powder cores. The phosphating effect on the magnetic properties and rust resistance of FeSiCr alloy powder was explored. The FeSiCr alloy powder was treated by different phosphoric acid content, and prepared to magnetic powder cores. The FeSiCr powder particles were analyzed by FTIR spectra, SEM, EDS, XRD and XPS in detail. It was found out that, the particle surface was covered uniformly by the phosphating film, which was mainly composed of FeHPO4, FePO4 and CrPO4. Magnetic analysis results were demonstrated that, with the increase of phosphoric acid content, magnetic permeability and saturation magnetic induction were gradually decreased, the core losses were slightly increased at low frequencies. Experimental results from salt spray were shown that the rust resistance of FeSiCr magnetic powder core was greatly improved once a certain phosphoric acid content was reached.