This work presents the study and development of an iron-based soft magnetic composite containing double layer insulating coating constituted of zinc oxide nanoparticles and vitreous boron oxide. The combination of these two insulating compounds improves significantly the electrical and magnetic behavior of SMCs due to a synergistic effect between the layers during processing. Dynamic losses were reduced nearly 78% and electrical resistivity was increased in almost 10 times for the double layered SMC compared to an SMC containing only vitreous boron oxide coating. Moreover, the permeability was at least 10% higher in the double-layered SMC than in the one coated only by ZnO nanoparticles. On the other hand, tensile rupture strength of double-layered SMC matches the one observed for the SMC coated by ZnO, which is nearly 30% lower than the strength of sample coated by B2O3. A mechanism responsible for the observed synergy is proposed in this paper based on the electric and magnetic performance of produced samples, on the thermal behavior of the coating observed on TGA and on the SEM images taken from several stages of samples production.