In this work the thermal decomposition characteristics of micron sized aluminum powder + potassium perchlorate pyrotechnic systems were studied with thermal analytical techniques. The results show that the reactivity of aluminum powder in air increases as the particle size decreases. Pure aluminum with 5 mu m particle size has a fusion temperature about 647 degrees C, but this temperature for 18 mu m powder is 660 degrees C. Pure potassium perchlorate has an endothermic peak at 300 degrees C corresponding to a rhombic-cubic transition, a fusion temperature around 590 degrees C and decomposes at 592 degrees C. DTA curves for Al-5/KClO4 (30:70) mixture show a maximum peak temperature for thermal decomposition at 400 degrees C. Increasing the particle size of aluminum powder increases the ignition temperature of the mixture. The oxidation temperature increased by enhance in the aluminum content of the mixture. (c) 2005 Elsevier B.V. All rights reserved.