Effects of Nano PbZrO 3 on the Decompositions of AP, RDX, HMX and the Combustion of (NG/NC) Propellant

Abstract

Nanoscale lead zirconate (PbZrO3) was prepared by using co-precipitation method, and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The catalytic performances of PbZrO3 on the decomposition of ammonium perchlorate (AP), cyclotrimethylene trinitramine (RDX) and cyclotetramethylene tetranitramine (HMX) were examined by differential scanning calorimetry (DSC). The thermal behaviors, nonisothermal decomposition kinetics of nitroglycerin/nitrocotton (NG/NC) double-base propellant with nano PbZrO3 (PbZrO3-DB) were also studied. The results show that PbZrO3 presents a typical perovskite structure. Nano PbZrO3 can remarkably reduce the thermal decomposition temperature and apparent activation energy of decomposition process(reduced by 21, 7.4 and 15 kJ/mol respectively). The thermal decomposition of PbZrO3-DB propellant is heterogeneous. Thermal decomposition mechanism of PbZrO3-DB propellant is a contracting cylinder with phase boundary reaction, and the kinetic equation is: $ \frac{{{\rm{d}}\alpha }}{{{\rm{d}}t}} = \frac{{{{10}^{16.7}}}}{\beta }2{\left( {1-\alpha } \right)^{1/2}}\exp \left( {-1.696 \times {{10}^5}/RT} \right)$ .Used as a combustion catalyst of NG/NC solid propellant, nano PbZrO3 can obviously increase the burning rate and decrease the pressure exponent (0.37-0.39) in the pressure range of 2-14 MPa. The catalytic combustion action of nano PbZrO3 is much better than that of PbO.