The reaction mechanism and activation energy (E-alpha) of aluminothermic reaction between Al and Nb2O5 were investigated under non-isothermal conditions using X-ray diffractometry (XRD) and differential thermal analysis (DTA) It was found that the mechanically alloyed Al-Nb2O5 powder mixture was converted to Al2O3/Nb composite in three stages and during the reduction intermediate Nb oxides (NbO2 and NbO) were formed Four isoconversional methods of Kissinger-Akahira-Sunose (KAS) Flynn-Wall-Ozawa (FWO) Tang and Starink were used to determine the value of E on a conversion fraction of alpha=0 5 for these three exothermic reactions The results showed that all methods lead to similar values of E and have a good agreement with one another Also, the isoconversional method of Starink was used to determine the variation of the activation energy E-alpha for three exothermic reactions with degree of conversion (alpha) It was revealed that the E-alpha for the first and third reactions are independent from a while different behavior was observed for the second reaction, where a decrease of E-alpha occurred in the conversion range of 06 <=alpha <= 0 95 (C) 2010 Elsevier B V All rights reserved