Adhesion coefficient and elastic properties of composite coatings on metallic substrate

In the present paper the elastic properties (apparent Young's modulus) of a composite coating (amine-epoxy resin + iron powder up to 40 vol.%) were examined by applying a vibrating reed technique (clamped-free configuration, frequency c.a. 100 Hz). Using tensile lap-shear strength tests (Instron machine) it was shown that adhesion coefficient of the examined composite coatings does not depend on iron powder content. In contrast to this Young's modulus of these coatings increases drastically with increasing powder content from 1.3 GPa (for powder free coating) to about 8 GPa (for 40 vol.% of iron powder). Moreover, Young's modulus also depends on powder grain dimensions and increases with decreasing a grain size. Magnetization measurements carried out for the composite coatings show some influence of powder grains interactions on magnetization processes at relatively weak magnetic fields i.e. up to μ0H = 0.8 T (μ0 is the vacuum permeability).