The Role of TiO2 on ZnAl2O4 Spinel Prepared by Direct Coagulation Casting Method: Physico-mechanical, Optical, Structural and Antimicrobial Properties

Abstract

This work represents the shaping of alumina–zinc oxide (AZ) samples with the direct coagulation casting method. The effect of zinc oxide (0, 10, 20, 30, and 40 wt%) and the firing temperatures on the phase composition, microstructure, physical properties, and mechanical properties of the AZ samples were studied. The effect of titanium oxide (2, 5, and 7 wt%) and the firing temperatures on the phase composition, microstructure, physical properties, and mechanical properties of the AZ sample with 40 wt% of zinc oxide were studied. Furthermore, the optical properties, magnetic properties, and antimicrobial activity were measured. The results indicate that the increase in zinc oxide enhances the formation of zinc aluminate, which has a gahnite phase. Moreover, increasing the zinc oxide increases the apparent porosity and decreases the grain size and bulk density at various firing temperatures. On the other hand, the addition of 5 wt% titanium oxide increases the bulk density to 3.5 g/cm3 compared to 1.72 g/cm3 with no titania. The apparent porosity and compressive strength reached 5% and 69.2 MPa after 5 wt% TiO2 addition; respectively, compared to 59% and 27.2 MPa with no titania addition. The prepared samples show promising optical band gap of 2.98–3.97 eV, a mixed magnetic behavior, and favorable antibacterial activity against E. coli, S. aureus, B. cereus strains.