چكيده به لاتين
Application of intermetallics such as TiCr2, have been emerged as hydrogen storage in recent years. In this research Magnesium, Titanium oxide and Chromium oxide used as economic primary materials for co-reduction and production of TiCr2 with combustion synthesis. Three approaches for synthesis of TiCr2 utilized in this research are Mechanical activation with planetary ball mill, microwave-combustion synthesis and microwave-combustion synthesis of activated powder. The obtained powder are characterized by X-ray diffraction, Scanning electron microscope and Energy-dispersive X-ray spectroscopy. The time and the spinning rate of milling are examined in the first approach. Metallic chromium began to produce after 10 hours of milling by reduction of Cr2O3. The amount of metallic chromium increased by increasing the time of milling up to 40 hours. Also, the amount of production of chromium in 300 rpm was more than 600 rpm. By X-ray diffraction analysis, we could not observe what happened to Titanium oxide. In The second approach, after microwave-combustion synthesis of mixed TiO2+Cr2O3+5Mg, Chromium oxide was reduced to metallic chromium by magnesium, and titanium oxide was reacted with magnesium oxide and Mg2TiO4 was formed. The unwanted Mg2TiO4 phase confined TiO2 to be reduced. The time of primary mechanical activation was 40 hours on the mixture of TiO2+Cr2O3 in the third approach and then the magnesium added to this activated powder mixture in different amounts and then microwave-combustion synthesis applied to the powder mixture. The temperature of combustion reaction decreased by increasing the magnesium amount and the Cr, TiO and MgCr2O4 were formed. The microwave heating step was done in vacuum, in order to prevent oxidation of magnesium at high temperature. Activation time of oxides mixture was 40 hours and then microwave-combustion synthesis was done on TiO2+Cr2O3+9.5Mg for 23 minutes in vacuum chamber. The vacuum chamber was effective because, the large amount of magnesium remained after process. In addition to large amount of chromium formed after process, titanium oxide was partially reduced and TiCr2 was formed. This shows that the reduction of titanium oxide and formation of TiCr2 needs time to be completed.
