Structural and electrical properties of γ-irradiated TiO2/Al2O3 composite prepared by sol-gel method

TiO2/Al2O3 system was prepared by sol-gel method and subjected to heating at 400 and 1000 deg. 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 deg. C consisted mainly of nanocrystalline rutile phase which turned by heating at 1000 deg. C to well crystallized rutile as major phase together with AlTiO3 and α-Al2O3 as minor phases. γ-Irradiation of, the system precalcined at 400 and 1000 deg. C exerted a small increase in the d-value of the main diffraction line of rutile phase in the system calcined at 400 deg. C. This treatment resulted in a significant increase in the electrical conductivity of calcined solids (102 to 103-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.