Parameters Affecting Hot Wire Ignition of Thermite Mixtures

摘要

Ignitors have traditionally been fabricated using pyrotechnics or explosives that are sensitive to hot wire ignition. Most of these devices have a 1- omega bridgewire and require 30 to 50 mJ of energy to function when delivered at a 3 to 5 A rate. The use of thermite mixtures has been established as thermal output charges in previous work. The components were simplified by using fewer chemical reactions to make the transition from the hot wire stimuli to the rapid burning of highly consolidated thermite mixtures. A second consideration is that the component should contain electrostatic discharge safe materials. Experiments have been conducted using a fine particle size - approximately 1- mu m constituents in Al/Fe sub 2 O sub 3 thermite blends consolidated to 1.8 g/cm exp 3 . The results of the tests have shown that, by using finely divided materials, sustained ignition can be obtained using a 3.5 A fire pulse into a 1- omega Tophet C bridgewire. Using the same thermite for the ignition charge, booster charge, and the high density output reduces the number of constituents in the component, and so simplifies the problem of long-term compatibility. The potential for reactions is greatly reduced by using an oxidizer that is inherently stable. (ERA citation 09:046544)