Doping hematite with bismuth to enhance its catalytic and oxidizing properties

Abstract

• Doping Fe 2 O 3 with Bi can significantly enhance its intrinsic reactivity. • The catalytic decomposition mechanism of HMX has been studied. • The ignition delay time is greatly shortened with the increase of Bi amount. • A high ignition performance of Al/Bix-Fe 2 O 3 can be obtained. Bismuth-cation modulated hematite (Bi-Fe 2 O 3 ) was prepared by a one-step hydrothermal method and used as a catalyst for the thermolysis of energetic materials (EMs) and oxidant in an Al-based thermite. The effects of the amount of Bi doped Fe 2 O 3 on the catalytic property and thermite behavior were investigated using differential scanning calorimetry (DSC). Thermogravimetry–infrared spectroscopy-mass spectrometry (TG/IR/MS) was used to study the thermal decomposition gases of cyclotetramethylenetetranitramine (HMX) with or without catalyst. Bi-Fe 2 O 3 was found to reduce the initial thermal decomposition temperature and activation energy of HMX, and change the decomposition mechanism. In addition, the thermite reaction of Al/Bi-Fe 2 O 3 is exothermic and faster than that of undoped Al/Fe 2 O 3 , resulting in more rapid energy release. Al/Bi-Fe 2 O 3 also shows a shorter ignition delay time than Al/Fe 2 O 3 . This study demonstrates Al/Bi-Fe 2 O 3 as an efficient advanced combustion catalyst for solid propellants.