Effect of hydrogen storage alloy with PTFE in high energy solid propellant

摘要

In solid propellants, aluminium (Al) is widely used to improve combustion and specific impulse performance. It can enhance reactivity and reduce two-phase flow losses of combustion by the replacement of micron scale Al with composite fuel particle. In this paper, the effect of hydrogen storage alloy with PTFE (M_(10)F_2) in high energy solid propellant was characterized using scanning electron microscope, differential scanning calorimeter, adi-abatic bomb calorimeter and underwater acoustic combustion speed tester. The high energy propellants containing M_(10)F_2 and Al were prepared by a vertical mixer. DSC-TG studies established the reaction of decomposition product of PTFE with Al at temperature of 570 ℃ in M_(10)F_2, which can not be observed in micron scale Al curves. It showed that melting temperature of Al can lower from 660℃ to 635 ℃ in GAPIM_(10)F_2 and catalyze decomposition of AP from 354 ℃ to 325 ℃ compared with GAP/Al/AP. which was attributed to the quicker ignition of Al, the more gaseous products of metal hydride and the oxidation of Al particles by fluorine from PTFE. Experiments were carried out in the pressure range of 3-9 MPa to determine the burning rates of cured solid propellant. The results indicated that M_(10)F_2based propellant showed a pressure exponent of 0.42. which increased 8.9% in propellant burning rate at 7MPa. To investigate the combustion efficiency, the content of active Al in residue after explosion heat test and the particle size in residue after combustion were analyzed. It showed the residue of M_(10)F_2 based propellant had a deceasing of content of active Al after explosion heat test and a smaller particle size after combustion. It is obvious indicated that the propellant containing M_(10)F_2 particles results in faster and more complete Al combustion. It is concluded that the hydrogen storage alloy with PTFE exhibits an efficient replacement of micron scale Al used in high energy solid propellant.