Microstructure Characterization of Mechanically-Induced Synthesizing of Zinc Metatitanate

Recently, extensive research focus was directed toward zinc titanates. Considerable interest had been revealed for their importance in various applications due to their low cost and being environmentally friendly. Zinc... [ view full abstract ]

Recently, extensive research focus was directed toward zinc titanates. Considerable interest had been revealed for their importance in various applications due to their low cost and being environmentally friendly. Zinc titanates exist in three multiphases resulted from the reaction of TiO₂ and ZnO. The metatitanate phase (ZnTiO₃) is distinct amongst analogous zinc titanates by its significance to development of dielectric materials for microwave frequencies and hence, significance in satellite communication systems industry. Pure product synthesis of ZnTiO₃ was reported elsewhere to be hard, and additives and/or heat treatments were required, which will add cost. 

The present investigation was focused on the preparation of ZnTiO₃ via solid-state reaction in an equimolar loose powder mixture of a-TiO₂ and ZnO. The reaction was conducted at room temperature by utilization of high mechanical force induced by ball milling at different time intervals up to 9 hrs, and without the need of additives or high temperature treatment of either reactants or product. The milled powders were characterized by XRD, SEM, HR-TEM and UV-vis reflectance spectroscopy. Accordingly, XRD results (Fig. 1) revealed the commence of the solid state reaction between the two metal oxides after 3 hrs of milling recorded by the evolution of tiny peak at 2θ = 29.9, which continued to increase as milling time increased. After 9 hrs, the dominant product was ZnTiO₃. Zn₂Ti₃O₈ existed as a minor product. Its existence was confirmed by HR-TEM (Fig.2). The minimum and maximum bandgap energy values of 3.14 eV and 3.29 eV were observed in a-TiO2/ZnO nanocomposite before milling and after milling for 9 hrs, respectively.