A microscale explosive initiator integrated with a reactive thin-filmed metallic bridge of boron/titanium laminated layers

Abstract

Aided by the advancement of microfabrication technologies, the electro-pyrotechnical initiators are being miniaturized into micron sizes to gain higher safety and reliability as well as lower mass manufacturing cost. One of the most important innovations proposed for the explosive initiator design in recent years would be the device integration with reactive thin-film metallic bridge which is composed of many laminated layers of different metals. The nanoscale boron and titanium (B/Ti) multilayers would be a feasible candidate for substantially improving the thermal initiation performance due to their fast reaction speed and high exothermic heat release. This study introduces the numerical modeling of ohmic heating in thin-film metallic bridge and the self-propagating intermetallic reaction in B/Ti laminated layers coupled with pulse-forming circuit in order to investigate the feasibility of such an initiator design. The computational results show that the ignition of intermetallic reaction and propagation of reaction wave in B/Ti multilayers of reactive initiator bridge are successfully modeled and simulated. The effects of several reactive bridge design parameters are investigated such as B/Ti layer thickness and its set number on bridge, electrical energy input in pulse form, and the existence of pre-mixing zone at bimetallic interface.