关键词: 硝基胍发射药, 超大弧厚, 力学性能, 燃烧性能

Abstract: With the transformation of the future war to the global mode of battle, combat weapons carrying ammunition will inevitably encounter extreme high or low temperature in storage, transportation and utilization environment. Nitroguanidine gun propellant has high energy and low ablative properties, which is widely used in large-caliber weapons. With the increase of the loading density of the propellant charge, the chamber pressure of the gun also increases. The main method to control the maximum chamber pressure of the gun is to improve the gradual increase of the propellant charge, while the main technical way is to increase the number of holes and arc thickness of the gun propellant. In order to study the mechanical and combustion properties of ultra-large thickness gun propellant (thickness 4.2mm) that used in a ship-borne large-caliber weapon, the thermal decomposition behavior, mechanical and combustion characteristics of ultra-large thickness nitroguanidine gun propellant with thickness 4.2mm have been studied by differential scanning calorimeter-thermogravimetric analysis (DSC-TG), closed bomb test, the charpy impact strength test and critical crushing strength test of drop hammer, respectively. The structure morphology and composition of the gun propellant is characterized through SEM, FT-IR and XPS. Results demonstrated that the combustion behavior ultra-large thickness nitroguanidine gun propellant under different temperatures, which maintains stable exhibiting smooth burning curves without step, that is accords with the combustion law of gun propellant. Compared with the approved azido-nitroguanidine gun propellant, under the same thickness and drop weight condition, the critical breaking height and impact strength of the ultra-large thickness nitroguanidine gun propellant are higher and larger under different temperature conditions, moreover, that of the impact strength of the simple supported beam is more than 1.6 times of the azido-nitroguanidine gun propellant. It demonstrated that the mechanical properties of ultra-large thickness nitroguanidine gun propellant is considerable excellent. Additionally, the ultra-large thickness nitroguanidine gun propellant exerts good thermal stability. Hence, this present work prospectively to provide basic support and guidance for the development of ultra-large thickness gun propellant used by large-caliber weapon for shipborne and other high-performance combat platforms in the future.

Key words: nitroguanidine gun propellant, ultra-large thickness, mechanical properties, burning behavior