Effect of viscosity on the magnetic permeability of Sendust-filled polymer composites

A flake-shaped Sendust/acryl suspension is tape cast and the effect of the viscosity of the suspension on the magnetic permeability of the resulting composite is investigated. The real part of the permeability of the composite is inversely proportional to the viscosity of the suspension, indicating that the lower the viscosity of the suspension, the higher the permeability of the composite. The viscosity of the suspension is controlled by adding a small amount of surfactant; an anionic surfactant is most effective for lowering the viscosity at a given concentration range. It is thought that using a suspension with a relatively low viscosity improves the permeability of the resulting composite due to the easy alignment of the flake-shaped filler with the plain direction of the sheet.