Studies on ilmenite for applications as electronic materials

Abstract

India is rich in Titanium reserves in the form of Ilmenite. Ilmenite is a wide band gap semiconductor. Synthetic Ilmenite when in solid solution with hematite, which is also another wide band semiconductor, is known to show non-linear current-voltage characteristics. Research on Ilmenite-hematite solid solutions have shown that addition of hematite (Fe2O3) even at small concentrations, to Ilmenite (FeTiO3) increases the conductivity of the solid solution due to the increase in the number of pairs of (Fe2+, Fe3+) and (Ti3+, Ti4+). Natural Ilmenite does contain a significant amount of hematite (Fe2O3) as observed in previous studies. The natural Ilmenite is therefore essentially a solid-solution of Ilmenite (FeTiO3) and Hematite (Fe2O3). In the present study, we have chosen Ilmenite from three different sources. Characterization has been carried out using X-ray diffraction, chemical analysis, scanning electron microscopy, and Mossbauer spectroscopy. The Electrical resisitivity of natural Ilmenite doped with small amounts of rutile and carbon has been carried out by the usual four probe method. It is has been observed the resisitivty of the samples varies widely. This behavior is explained on the basis of the relative content of two isomeric states of Fe.