Electrical, magnetic, and corrosion resistance properties of TiO2 nanotubes filled with NiFe2O4 quantum dots and Ni–Fe nanoalloy

This work was carried out as an integral part of a project aiming to improve the catalytic, electrical, magnetic, and mechanical properties of synthesized TiO2NTs filled with metal ferrites. TiO2 nanotubes in the anatase-phase (TiO2NTs) were prepared using a hydrothermal method followed by ion exchange and phase transformation. The obtained TiO2NTs were filled with NiFe2O4 quantum dots (QDs) and then reacted at 600 °C in a reducing atmosphere to produce TiO2NTs filled with Ni–Fe nanoalloy. The effect of the TiO2NTs’ coating on the dissolution rate of Ni–Fe nanoalloy in 0.5 M HCl solution was monitored chemically using a weight-loss technique that was performed at different temperatures. The TiO2NTs’ coating exhibited high protective performance and amazing corrosion resistance. The magnetic properties of the TiO2NTs filled with NiFe2O4 QDs and Ni–Fe nanoalloy compacts were analyzed by a vibrating sample magnetometer. The electrical conductivity-temperature dependence of anatase TiO2NTs, anatase TiO2NTs filled with NiFe2O4 quantum dots, anatase TiO2NTs filled with Ni–Fe nanoalloy, and NiFe2O4 was measured in the temperature range of 25–850 °C. The conductivity increased with temperature, indicating the semiconductor-like nature of the sample. During cooling, the conductivity retains values higher than that obtained during heating.