New insights in nano-copper chromite catalyzing ultrafine AP: Evaluation of dispersity and mixing uniformity

Abstract

Improving the application of nanomaterials has always been a research hotspot in the field of energetic materials (EMs) due to their obvious catalytic effect on the EMs, especially the uniformly dispersed nanomaterials. However, few studies have reported the dispersion of nanomaterials. In this study, the dispersity and mixing uniformity of nano-CuCr2O4 was evaluated based on the difference of solid UV light absorption between the nano-catalytic materials and EMs. The nano-CuCr2O4/ultrafine AP composites with different dispersity of nano-CuCr2O4 were prepared by manual grinding and mechanical grinding with different grinding strength and griding time. And then, the absorbance of different samples at 212 nm was obtained by solid UV testing due to the high repeatability of the absorbance at 210–214 nm for three parallel experiments, and the dispersity of different samples was calculated through the established difference equation. Furthermore, the samples were characterized by XRD, IR, SEM, EDS, DSC and TG-MS, which confirmed that different mixing methods did not change the structure of the samples (XRD and IR), and the mixing uniformity improved with the increase of grinding strength and grinding time (SEM and EDS). The scientificity and feasibility of the difference equation were further verified by DSC. The dispersity of nano-CuCr2O4 exhibits a positive intrinsic relationship with its catalytic performance, and the uniformly dispersed nano-CuCr2O4 significantly reduces the thermal decomposition temperature of ultrafine AP from 367.7 to 338.8 °C. The TG-MS patterns show that the dispersed nano-CuCr2O4 advanced the thermal decomposition process of ultrafine AP by about 700 s, especially in the high temperature decomposition stage, and the more concentrated energy release characteristic is beneficial to further enhance the energy performance of AP-based propellants. The above conclusions show that the evaluation method of dispersity based on solid UV curves could provide new ideas for the dispersity characterization of nano-catalytic materials in EMs, which is expected to be widely used in the field of EMs.