The Department of Defense (DoD) has recognized heavy metal contamination as a critical environmental problem and assumed responsibility for reducing the use of lead (Pb) in its munitions. A SERDP Exploratory Development (SEED) project, WP-1183, focused on the feasibility of eliminating the use of heavy metals in the manufacture of medium-caliber lead-free electric primers (LFEP). The SEED project successfully demonstrated that nontoxic Metastable Intermolecular Composite (MIC) materials could be substituted for the normal complement of primary explosives based on heavy metal compounds. This project was a follow-on effort focused on refining the use of this technology for LFEP applications.
The objective of this project was to develop a reliable and effective electrically initiated medium-caliber primer that does not utilize environmentally harmful materials.
MIC has emerged as a novel energetic material with desirable properties in many ordnance-related applications, including its use as a substitute for primary explosives in applications such as the LFEP. The naturally benign nature of the MIC material makes it an excellent candidate for research in environmentally sensitive applications. Two electric primer configurations (conventional and exploding foil) that utilize environmentally benign MIC materials were investigated for the direct replacement of Pb-based conventional toxic primer systems. Critical factors in determining the feasibility of this technology included functional reliability, manufacturing costs, production and operational safety, performance under specified environmental conditions, and life-cycle costs. Performance and reliability changes due to aging from component interactions and environmental weathering were thoroughly investigated. The end product was a technical data package for an LFEP design.
The down-selected candidate for the LFEP program was KTHU-22. This baseline primer mix consists of 76% MIC (Technanogy 50-nm Al powder), 20% BTATZ, 2% Kel-F, and 2% carbon. The action time for ambient and cold temperatures consistently fell within specifications.
Major benefits derived from substituting MIC materials in medium-caliber ammunition primers include reduced health and environmental risks to factory workers during primer mix manufacture and ammunition production processes; reduced risk to operational users who may be confined in spaces contaminated by residual weapons system gases containing Pb; and cost savings from the avoidance of cleanup processes at manufacturing and operational locations.