Pressure effects on pyrotechnic delays of the molybdenum family

Abstract The effects of ambient pressure, from 22800 down to 27 mm of Hg, on molybdenum delay mixes of high, medium and low burning rates have been investigated. As is typical of most gasless delay compositions, rather small pressure coefficients are obtained. Discontinuity of ignition propagation at reduced pressure is only observed in delay mixes of slow burning rate, or low molybdenum content. It is attributed to the diminution of rate of heat release. Molybdenum content has been recognized as the dominant factor, for increasing it will reduce the pressure effects significantly. On the other hand, the variation of burning process with ambient pressure is not associated with the degree of compaction of the delay mixes. It is found that the pressure coefficients of molybdenum delay mixes can be further diminished by the addition of metal fluorides. Among the fluorides employed, lithium fluoride results in better performance at the moderate uantity of 3% by weight.