According to the present invention there is provided an improved lead-free percussion primer composition comprising particulate aluminum and molybdenum trioxide having a particle size of about 0.1 mm or less. The molybdenum trioxide is present in an amount sufficient to oxidize the aluminum particles.

In a preferred embodiment, TEFLON powder (polytetrafluoroethylene) is mixed with the particulate aluminum and molybdenum trioxide.

In another embodiment of the present invention, a lead-free percussion primer composition comprises particulate aluminum and polytetrafluoroethylene having a particulate size of about 0.1 mm or less.

Where the primer composition according to the present invention comprises aluminum and molybdenum, it is preferred that the aluminum constitute about 45 wt% of the composition. When the primer composition of the present invention comprises particulate aluminum and TEFLON, the aluminum constitutes about 50 wt% of the composition.

A primer cup assembly conventionally used in ammunition is shown generally at 1 (Fig. 1) and comprises a brass primer cup 3 having a rim portion 5. The primer cup portion 3 contains a primer mix 7. A paper disc 9 rests on the surface of primer mix 7 so as to contain primer mix 7 in said primer cup assembly 3 and to prevent moisture from reaching the primer mix 7. A saddle shaped anvil indicated generally at 10 is shown with a top surface 4 and a cross sectional area 13. The anvil 10 rests upon and is in contact with paper disc 9.

The percussion primer composition of the present invention, unlike the commonly used lead-based explosive compositions which detonate, react together and cause an extremely intense exothermic reaction. This reaction liberates a great amount of heat and burning particles which causes the main charge of gun powder in the ammunition to ignite and rapidly burn.

In a preferred embodiment of the invention, the percussion primer composition 7 is a mixture of aluminum powder and molybdenum trioxide or a mixture of aluminum powder and Teflon (polytetrafluoroethylene). The particle sizes of the powder is preferably about. 1 mm or less, more preferably from about. 02-. 05 mm. For the Al/MoO3 combination, aluminum typically constitutes about 45 wt% and MoO3 typically constitutes about 55 wt% of the composition. Weight percentages for the Al/Teflon combination are about 50 wt% for each of the species.

The by-products of the reaction of aluminum and molybdenum trioxide consists of alumina (a ceramic) and molybdenum, both non-toxic and environmentally benign. A substitute, lead-free, primer mix would also have to provide the same or greater performance (energy output) and reliability under stated conditions (-65°F to +160°F, total propellant ignition). MIC materials satisfy these requirements.

The primer compositions of the present invention provide a significant increase in output energy as compared to a standard primer mix and can be tailored to provide optimal performance. Thus, the primer composition of the present invention provides greater performance in primer mix performance while maintaining the current design of existing percussion primers. This eliminates the need to redesign the primer and associated components. The relative insensitivity of the primer compositions of the present invention to low temperatures provides a primer mix that will reliably function at temperatures as low as-65°F. With a cook off temperature that approaches 900°F, these compositions far exceed the required high temperature requirement of +160°F for the safe use of military ammunition.