Effect of some catalysts on combustion of double-base propellants

The effect of PbO2, SnO2, TiO2, and Bi on the combustion of propellants of various compositions is investigated. It is established that SnO2, TiO2, and Bi have a significant effect on the burning rate of propellants without carbon black and additional plastifiers. A marked catalytic effect of PbO2 is manifested only when its content is higher than 5%. It is shown that the addition of SnO2 and PbO2 to propellants leads to formation of a carbon black matrix on the burning surface, on which catalyst particles build up. With the addition of carbon black to propellants, the catalytic action of TiO2 and Bi is enhanced only slightly, and the effect of SnO2 at moderate pressures is markedly reduced due to a considerable increase in the degree of reduction of the active form of (SnO2) catalyst up to its inactive forms (SnO and beta-Sn).