Shock sensitivity of Diaminoazoxy Furazan (DAAF) using an instrumented Small Scale Gap Test

摘要

Diaminoazoxy furazan (DAAF) is an insensitive high explosive first synthesized in Russia in the 1980s and the synthesis path was developed at Los Alamos National Lab in the early 2000s. DAAF has safety eharaeteristics (impact, friction) similar to TATB, but a critical diameter of less than 3mm and shock sensitivity similar to HMX. The combination of these characteristics is unusual and makes DAAF an interesting explosive that is suitable for booster applications. Gap testing is the ubiquitous test to statistically quantify shock sensitivity, but it exists in many forms. We used the LANL small scale gap test for our studies because it has the advantage of requiring very little material (less than 9g per test) and can be easily instrumented. While the gap test is statistical in nature, employing the Bruceton up-down method to determine a 50% point of detonation, we wanted to measure the shock velocity of the donor explosive into DAAF. To accomplish this, a scries of shock wave experiments were conducted using representative gaps to capture the input pressure to the DAAF and to understand the shock pressure required for detonation. The experiments included in this paper investigated the effects of particle size on the shock sensitivity of DAAF. Three particle sizes (<5(μm. 40μm, and 80μm) were tested at two densities (91% TMD and 97% TMD). The 80μm particle size DAAF was obtained through the historic synthesis process, which also produces several energetic impurities. A novel synthesis process, which was developed at LANL over the past two years, produced DAAF with a 40 μm particle size. Crash precipitating the 80 μm DAAF in dimethyl sulfoxide, to render pure, yielded small (<5μm) particle size DAAF. As expected the shock sensitivity is depressed by increasing density (decreasing porosity) and shows interesting trends with respect to particle size.