Mechanically activated combustion synthesis of Ti3AlC2/Al2O3 nanocomposite from TiO2/Al/C powder mixtures

Abstract

Ti3AlC2/Al2O3 nanocomposite powder was synthesized by mechanical-activation-assisted combustion synthesis of TiO2, Al and C powder mixtures. The effect of mechanical activation time of 3TiO2-5Al-2C powder mixtures, via high energy planetary milling (up to 20 h), on the phase transformation after combustion synthesis was experimentally investigated. X-ray diffraction (XRD) was used to characterize as-milled and thermally treated powder mixtures. The morphology and microstructure of as-fabricated products were also studied by scanning electron microscopy (SEM) and field-emission gun electron microscopy (FESEM). The experimental results showed that mechanical activation via ball-milling increased the initial extra energy of TiO2-Al-C powder mixtures, which is needed to enhance the reactivity of powder mixture and make it possible to ignite and sustain the combustion reaction to form Ti3AlC2/Al2O3 nanocomposite. TiC, AlTi and Al2O3 intermediate phases were formed when the initial 10 h milled powder mixtures were thermally treated. The desired Ti3AlC2/Al2O3 nanocomposite was synthesized after thermal treatment of 20 h milled powder and consequent combustion synthesis and FESEM result confirmed that produced powder had nanocrystalline structure.