Novel Magnetic Inorganic Composites: Synthesis and Characterization

Abstract

The addition of magnetic particles to inorganic matrices can produce new composites exhibiting intriguing properties for practical applications. It has been previously reported that the addition of magnetite to concrete improves its mechanical properties and durability in terms of water and chloride ions absorption. Here we describe the preparation of novel magnetic geopolymers based on two different matrices (G1 without inert aggregates and G2 with inert quartz aggregates) containing commercial SrFe12O19 particles with two weight concentrations, 6% and 11%. The composites’ characterization, including chemical, structural, morphological, and mechanical determinations together with magnetic and electrical measurements, was carried out. The magnetic study revealed that, on average, the SrFe12O19 magnetic particles can be relatively well dispersed in the inorganic matrix. A substantial increase in the composite samples’ remanent magnetization was obtained by embedding in the geopolymer SrFe12O19 anisotropic particles at a high concentration under the action of an external magnetic field during the solidification process. The new composites exhibit good mechanical properties (as compressive strength), higher than those reported for high weight concretes bearing a similar content of magnetite. The impedance measurements indicate that the electrical resistance is mainly controlled by the matrix’s chemical composition and can be used to evaluate the geopolymerization degree.

Heating ability of amine functionalized Fe3O4 as a function of field amplitude and frequency for hyperthermia application

“…Transmission electron microscopy (TEM) micrographs, as shown in figures 4(A)-(B), were employed to characterize the size and morphology of Fe 3 O 4 and Fe 3 O 4 -NH 2 nanoparticles. The images reveal that the nanoparticles appear as dark spots against a bright background and exhibit a spherical and slightly elongated [3,11,12,14]. To confirm the saturation values and the effective anisotropy constant (K eff ), The following formula employ the law of approach to saturation which explains the magnetization close to the saturation [6]: And the following formula may be used to get the effective anisotropy constant (K eff ) using the parameter b:…”

“…When an external magnetic field is applied, the magnetization can be reversed by overcoming an energy barrier associated with this alignment.An increasing M/Ms-H curve means that the material responds more effectively to an applied magnetic field. This leads to enhanced energy absorption from the magnetic field, which in turn results in more efficient and controlled heating of the targeted tissue [11].…”

“…Moreover, the incorporation of magnetic particles into inorganic matrices yields novel compounds with noteworthy properties that hold significant potential for various practical applications. Notably, these compounds demonstrate the capacity to enhance the mechanical properties of concrete [11].…”

Magnetic-assisted preparation and performance control of Fe3O4/PVDF gradient magnetic composites

“…In the forming process of magnetic composites, different base materials (inorganic or organic) can be selected according to actual needs. 7,8 Wang et al 9 prepared ordered Co-Ni coreshell magnetic nanorod arrays using a two-step electrodeposition process, providing the possibility of adjusting appropriate coercivity at the nanoscale. Zhu et al 10 achieved continuous and controllable adjustment of magnetic parameters by utilizing different bending radii of membranes.…”

Geopolymers—Design, Preparation, and Applications

“…Assuming that the addition of magnetite to concrete improves its mechanical properties and durability in terms of water and chloride ions absorption, Sgarbossa et al, proposed the design and preparation of novel magnetic geopolymers based on matrices with and without inert quartz aggregates, containing metal particles at different concentrations [ 11 ]. By using a method of general application, considering the wide range of experimental parameters and modulability of the geopolymers preparation, together with the different types and amounts of magnetic particles, they obtained composites with a compressive strength higher than those reported for high weight concretes containing a similar magnetite amount.…”