Development of alternative catalysts for boron-based solid rocket fuels

In this thesis study, the aim was to develop, synthesize, characterize, and test perovskite-structured catalysts to enhance the performance of boron-based composite fuels. The citrate-nitrate method was employed for catalyst synthesis, and the structural properties of the synthesized catalysts were analyzed using advanced characterization techniques. The crystal structure of the catalysts was determined through XRD, and their surface areas were measured using the BET method. All catalysts successfully formed the perovskite crystal phase and exhibited a porous, sponge-like morphology, as confirmed by the analyses. The effects of the catalysts on the thermal decomposition behavior of ammonium perchlorate (AP) were evaluated in detail using TGA and isoconversional methods. The analyses revealed that the La₀.₈Ca₀.₂Fe₀.₅Co₀.₅O₃ catalyst reduced AP's high decomposition temperature (HDT) by 26.3%, bringing it down to 335.1°C. Furthermore, this catalyst decreased AP's activation energy by 43.1%, from 144.69 kJ/mol to 82.35 kJ/mol. These results clearly demonstrate the potential of the La₀.₈Ca₀.₂Fe₀.₅Co₀.₅O₃ catalyst to improve the thermal behavior of AP. The combustion tests revealed that the La₀.₈Ca₀.₂Fe₀.₅Co₀.₅O₃ catalyst significantly reduced the pressure exponent (n) from 0.4615 to 0.2419 compared to non-catalyzed fuel, while achieving the highest combustion rates at 20, 40 and 60 bar pressures. At a pressure of 40 bar, the Fe₂O₃ catalyst increased the combustion rate of pure boron by 12.8%, whereas the La₀.₈Ca₀.₂Fe₀.₅Co₀.₅O₃ catalyst achieved the highest increase of 29.6%. These findings highlight the superior performance of the catalyst in both enhancing combustion rates and reducing pressure dependency. Finally, SEM and EDX analyses confirmed the homogeneous distribution of boron-based composite fuel components. The findings demonstrate that the La₀.₈Ca₀.₂Fe₀.₅Co₀.₅O₃ catalyst plays a highly effective role in improving the performance of boron-based composite fuels. The study suggests that future research should focus on developing new approaches to eliminate the boron oxide layer to further enhance the performance of boron-based fuels.