Impact of Hard Magnetic Nanocrystals on the Properties of Hardened Cement Paste

In this work, nano-sized hard magnetic gallium-substituted iron oxide crystals, wherein gallium is used to stabilize the metastable epsilon iron oxide phase, were added to cement-water suspensions at different ratios, which were subsequently hydrated for at least 28 days. It is shown that higher contents of such nanocrystals in the hardened cement paste introduce a magnetic moment, whereas the mechanical properties remain unchanged compared to non-blended hardened cement paste for a wide concentration range. The impact of different amounts of incorporated hard magnetic Ga0.043Fe1.957O3 (85 % & epsilon; and 15 % & alpha; phase) nanocrystals (NCs) on the physical properties of hardened cement paste is shown. By adding these Fe2O3 NCs it is possible to modify the manifold properties simultaneously, thus, enabling fine-tuned buildings or coatings. image