Study of Polyelectrolyte/Silica Coatings Based on Layer-by-Layer Assembly on Iron Powder for Soft Magnetic Composite Materials

Soft Magnetic Composites (SMCs)—powdered ferromagnetic materials characterized by high macroscopic electrical resistivity—constitute an excellent resource for electrical machines with non-traditional magnetic flux configurations, such as axial flux machines. Their adoption is currently expanding within the mass production of small components, particularly in the automotive sector. Consequently, numerous research activities focus on performance optimization to maximize and harmonize the mechanical, energetic, and magnetic properties of SMCs. In this context, the layer-by-layer (LbL) chemical deposition process offers multiple degrees of freedom regarding the types, quantities, and arrangements of materials used to construct insulating and binding layers. This study presents a specific system comprising a polymer and nanometric silica, investigating the influence of several process parameters on the overall performance of the final material. The resulting samples were characterized using a hysteresigraph to determine their magnetization curves, relative magnetic permeability, and specific losses across different frequencies. Additionally, mechanical properties were evaluated through transverse rupture strength tests.