| Abstract: | The ammonium perchlorate (AP)-oxidized composite propellants, each of which contains separately copper chromite (CC) as a burning rate adjuster and carbon black (CB) as an opacifier, have been ignited at subatmospheric pressures of argon gas by means of a carbon dioxide laser, and the effects of the additives on the ignition behavior have been studied. It has been found that copper chromite shortens the ignition time especially below 100 torr and that at the same time it enhances the ignitability, i.e., self-sustaining ignition. Carbon black, being an opacifier decreasing reflectivity and increasing radiative absorption at propellant surface, can not be recognized to be an active catalyst in ignition at subatmospheric pressures. The data of differential thermal analysis (DTA) for above specimens have indicated that the maximum exothermic peak temperature is shifted toward a lower one with the increase in CC concentration, the exothermic peak structure becoming sharper. However, CB addition to the basic propellant makes exothermic peaks less distinct. The results of DTA support those obtained from the ignition experiments above. |
