Burning rate modulation for composite propellants by interfacial control of Al@AP with precise catalysis of CuO

Burning rate modulation is a critical but challenging technology for solid propellants’ design. Great efforts have been made to synthesize and utilize catalysts to modify the pressure exponent ( n ), but poor catalytic efficiency and lower energy level of conventional catalysts limit their further applications. In this research, interfacial control of Al@AP together with precise catalysis of CuO is represented for the purpose of pressure exponent reduction and combustion performance improvement. The core-shell structured Al@AP and Al@AP/CuO composites were prepared and applied into HTPB/Al/AP composite propellants. These prepared propellants have the same formula but different micro-structures of ingredients, leading to varied combustion performance, in terms of the burning rates, combustion wave structures, flame spectra, agglomeration processes of Al particles and condensed combustion products . The investigation results show that by using interfacial control of Al@AP and precise catalysis of CuO, the n of involved propellants over 1–4 MPa can be greatly decreased from 0.42 to 0.21 and the agglomeration of Al could be effectively inhibited. In addition, propellants based on Al@AP and Al@AP/CuO interfacial controls of this research are summarized and compared together with those based on Al@RDX published recently, to present overall characteristics of interfacial control techniques, which could lead to the development of new smart controllable propellants.