Determination of a quantitative relationship between deposition duration and magnetic performance of soft ferromagnetic composites via data-analysis and theoretical models.

[Display omitted] • Fe–Si/SiO 2 soft ferromagnetic composites prepared via novel two-step method. • SiO 2 insulation coating thickness increased linearly with deposition duration. • SiO 2 insulation coating process had no influence on Fe–Si crystal structure. • SiO 2 insulation coating thickness predicted total core loss. • Quantitative equations relating electromagnetic properties to deposition duration. The industrial production of soft ferromagnetic composites demands a quantitative description of process parameters and magnetic performance. Here, Fe–Si/SiO 2 soft ferromagnetic composites were prepared via a two-step method combining chemical vapour deposition and hot-pressed sintering. Investigations of surface and section morphology, phase composition and crystal structure were undertaken to characterise the deposition duration-dependence of SiO 2 insulation coating thickness in Fe–Si/SiO 2 soft ferromagnetic composites. A vibrating sample magnetometer, a resistivity tester and a B–H analyser were used to study the magnetic behaviours of Fe–Si/SiO 2 soft ferromagnetic composites. Based on curves of deposition duration-dependence of SiO 2 insulation coating thickness and other theoretical models, quantitative relationships between deposition duration and magnetic performance were determined for Fe–Si/SiO 2 soft ferromagnetic composites. These results demonstrate that the coating and crystallisation of SiO 2 insulation coatings had no influence on the crystal structure of Fe–Si substrate particles and that SiO 2 insulation coating thickness increased linearly with deposition duration. Total core loss of Fe–Si/SiO 2 soft ferromagnetic composites was strongly predicted by SiO 2 insulation coating thickness. A quantitative equation relating magnetisation intensity to Fe–Si/SiO 2 soft ferromagnetic composite deposition duration was derived on the basis of experimental data and subsequent model selection. Additional quantitative equations relating electrical resistivity and eddy current loss to Fe–Si/SiO 2 soft ferromagnetic composite deposition duration were determined according to electromagnetic theory. These results establish a precise adjustment mechanism for magnetic behaviour in Fe–Si/SiO 2 soft ferromagnetic composites and promote the industrialisation of a new preparation process combining chemical vapour deposition and hot-pressed sintering. [ABSTRACT FROM AUTHOR]