Structural and electrical properties of γ-irradiated TiO 2/Al 2O 3 composite prepared by sol–gel method

Abstract

TiO 2/Al 2O 3 system was prepared by sol–gel method and subjected to heating at 400 and 1000 °C. The obtained solids were irradiated at different doses of γ-rays (10–150) kGy. Structural and electrical properties of the solids investigated have been studied using XRD, EDX, SEM and electrical conductivity measurements. The results revealed that the system calcined at 400 °C consisted mainly of nanocrystalline rutile phase which turned by heating at 1000 °C to well crystallized rutile as major phase together with AlTiO 3 and α-Al 2O 3 as minor phases. γ-Irradiation of, the system precalcined at 400 and 1000 °C exerted a small increase in the d-value of the main diffraction line of rutile phase in the system calcined at 400 °C. This treatment resulted in a significant increase in the electrical conductivity of calcined solids (10 2 to 10 3-fold). Furthermore, γ-rays created some holes (evidenced by SEM investigation). These created holes might increase the mobility of charge carriers (positive holes) increasing thus the electrical conductivity of irradiated solids.