**4. Conclusions**

Mg2TiO4 nanocrystalline with spinel structure were synthesized from high purity MgO and TiO2via high energy ball milling techniques. The impact of milling time on particle size, crystal structure and the microstructure of mechanically derived Mg2TiO4 nanocomposite powders were investigated using X-ray diffraction, scanning electron microscopy and transmission electron microscopy (TEM) techniques respectively. Williamson-Hall method was employed to understand the origin of the broadening of the X-ray diffraction peaks. It was confirmed that the W-H method is a more accurate method as compared to the Scherrer method for the estimation of crystallite size of the Mg2TiO4 nanocomposite materials. Further, the thermal decomposition behavior of the milled powders was examined by a thermo-gravimetric analyzer (TGA) in argon atmosphere. The UV–visible spectra showed strong bandgap absorption at ~356 nm and with an increase of milling times from 0 to 35 hrs, there is an increase of the band-gap from 3.68-3.78 eV. The Mg2TiO4 nano- powders synthesized via mechanical alloying method showed promising optical properties which is suitable for commercial optoelectronic applications. Also, the high optical absorption edge makes this material as suitable UV light absorber. Moreover, Mg2TiO4 is an excellent microwave dielectric material having wide band gap and high refractive index and practically useful for various optical and electronic applications.
