Preparation And Characterization Of Nanothermite Co₃O₄/Al And Its Effect On Combustion Performance

In order to study the combustion reaction performance of nanothermites,the complex process and the rule of reaction between oxides and fuels were investigated in this paper.The effects of different nanothermites on the energy release,combustion flame propagation performance and pressure generation were investigated in term of morphology and interface contact.Firstly,the morphology control of nano-Co₃O₄ prepared by hydrothermal method was discussed.Co₃O₄ particles with different nanostructures were prepared by changing the reaction conditions such as reactant concentration,reactant ratio and reaction time.Then,several different types of nanothermites were prepared to make nanospheres Co₃O₄ and nanorods Co₃O₄ mix with Al using physical mixing,GO self-assembly and P4VP self-assembly methods,respectively.It was found that the heat released from the spherical nanothermites prepared by GO self-assembly was 2618J·g-1,and the heat released was 2612J·g-1 by P4VP self-assembly method.Subsequently,the prepared nanothermites was filled in quartz tube,and the flame propagation behavior of nanothermites in the combustion channel was recorded by high speed camera,and the combustion behaviors were studied from the aspect of different preparation methods,oxide morphology and charge density.The results showed that the convective effect was dominant in the process of flame propagation,but it can not form a stable burning rate at the initial stage of flame growth.Finally,the pressure generation in nanothermites was tested by a closed bomb.The experiment results showed that the combustion pressure of the nanorods Co₃O₄/Al prepared by physical mixing method was 14.25MPa under ignition condition.The spherical Co₃O₄/Al prepared by GO self-assembly method had a short ignition delay time of 3.8ms.The sphere Co₃O₄/Al prepared by P4VP self-assembly method generated the pressure up to 12.11 MPa and the pressurization rate was 31.938GPa·s-1.The results also indicated that the self-assembly method can improve the interface contact between the components and enhance the combustion reaction performance.