Influence of mechanical activation on microstructure and crystal structure of sintered MgO-TiO2 system

S Filipovic,S Markovic,N Obradovic,M Mitric,M.M Ristic,V.B Pavlovic

doi:10.2298/sos100518002f

Abstract

Mixtures of MgO-TiO2 were mechanically activated using high-energy planetary ball mill during 5, 10, 20, 40, 80 and 120 minutes. Sintering process was preformed in air at 1100o-1400oC for 2h. The decrease in powder?s particle size was noticed as the time of mechanical activation increased and confirmed by particle size analyzer. XRD analyses were performed in order to acquire the information about phase composition. Different ratio mixtures of MgTiO3 and Mg2TiO4 are present within all sintered samples. The effect of tribophysical activation on microstructure was investigated by scanning electron microscopy. The differential thermal gravimetric analysis has been performed in order to investigate thermal behaviour of the mixtures.

Highlights

Development of dielectric materials is increasing with a rapid progress in mobile and satellite communications systems, where magnesium titanates find their place owing to good dielectric properties
Scanning electron micrographs indicate a difference between the starting and activated powders morphology confirming the changes taking place during the mechanical activation
Based on XRD results, the phase transition of TiO2 anatase → TiO2 II brookite → TiO2 rutile is observed after 5 minutes of mechanical treatment; the first appearance of the magnesiumtitanate phase MgTi2O5 was found to occur after 20 minutes of mechanical treatment; the MgTiO3 perovskite phase was noticed after 40 minutes

Summary

Introduction

Development of dielectric materials is increasing with a rapid progress in mobile and satellite communications systems, where magnesium titanates find their place owing to good dielectric properties. It has been established that, these materials, which are based on binary magnesium titanates (MgTiO3 and Mg2TiO4) can be applied in MW engineering. These materials differ extremely low dielectric loss in the microwave range and high dielectric constant [1,2,3]. MgO-TiO2 system has been studied extensively and the existence of three stabile phases (MgTiO3, Mg2TiO4 and MgTi2O5) has been reported in literature. The magnesium titanates are normally synthesized at relatively high temperatures of 1400oC by solid-state reactions between MgO and TiO2

Methods

Results

Conclusion