Improving the energy release characteristics of PTFE/Al by doping magnesium hydride

Magnesium hydride (MgH2) was doped into PTFE/Al to improve the energy release characteristics of the material system and strive for better application in military engineering. Five types of PTFE/Al/MgH2 reactive materials with different MgH2 content were prepared by molding sintering method. The dynamic mechanical properties of the materials were studied by performing split-Hopkinson pressure bar (SHPB) tests and scanning electron microscope characterizations. The thermal behavior, reaction energy, reaction process and reaction mechanism were systematically investigated by conducting thermogravimetry-differential scanning calorimetry tests, oxygen bomb calorimeter measurements, X-ray diffraction and SHPB tests. The results show that MgH2 particles less than 10% content contribute to heightening the dynamic mechanical properties of PTFE/Al system. The product Mg generated by decomposition of MgH2 can not only react with gas phase C2F4+ but also undergo a Grignard-type reaction with condensed PTFE. The reaction energy and ignition threshold of PTFE/Al/MgH2 reactive materials enhance monotonously as MgH2 content rose. With the increase of MgH2 content from 0% to 20%, the reaction time is prolonged as well as the reaction intensity is enhanced dramatically arising from the massive water vapour produced by the reaction between O-2 and H-2. The gaseous products generated can form a high pressure shortly after the reaction, which helps to elevate the damage effect of the PTFE/Al system. (C) 2022 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd.