You are all cordially invited to hear Christian Poupart present his MASc seminar talk on “Control of ignition temperature in hybrid thermite-intermetallic reactive materials”. The abstract of the talk is below. The talk will start promptly at 2:30pm – the seminar form will not be available to late-comers.
Date: Friday October 31st
Room: CBY B205
Thermite and intermetallic mixtures have received renewed interest in recent years. Such reactive materials have been used since the early 1900s as welding agents for railway tracks. New technologies have recently made these compounds more attractive. This work focuses on a thermite mixture of Aluminum Copper-oxide. This reactive mixture is largely popular due to its ability to create a substantial amount of gaseous products, and a reaction front that can propagate at supersonic speeds. This compound can be used in many applications involving propellants, pyrotechnics and military. Ignition temperatures for this mixture have been reported to be approximately 660oC. This study will focus on lowering the ignition temperature of Al-CuO.
Studies have shown that by reducing particle size, and increasing surface contact of constituents, reaction kinetics can be improved dramatically. In this work we investigate the effects of arrested reactive milling (ARM) on the reaction kinetics of mixtures of Aluminum Copper-Oxide and Nickel-Aluminum. Ni-Al is a mixture called an intermetallic. Intermetallic reactions are usually gasless, and highly exothermic. Previous reports have shown that ARM significantly reduces the ignition temperature of Ni-Al. The microstructure of these compounds becomes dependent on the duration of the milling process. Mechanical milling of powders reduces the particle size, and creates a constituent interface at the sub-micron level. Ignition temperatures of Al-CuO and Ni-Al are strongly dependent on the milling time. The ignition temperature of Al-CuO was reduced to 600oC for milling time of 16 minutes. The ignition temperature of Ni-Al was reduced from 660oC down to 207oC for a milling time of 40 minutes. Hybrid mixtures of Al-CuO-Ni are then created with the milled constituents, at different concentrations. Results show that the ignition temperature of a hybrid system is dependent on the concentration of constituents. The lowest ignition temperature observed was approximately 250oC for a milled hybrid mixture containing 25% (by mass) of 16 minute milled Al-CuO and 75% milled Ni-Al.