MAGNESIUM DIBORIDE AS A SYNERGISTIC ADDITIVE IN AP/HTPB COMPOSITE PROPELLANT

• DOI: 10.1615/intjenergeticmaterialschemprop.2025054746
• Publication Date: 2025-01-30T18:33:31Z
• Authors: Mikel J. Zaitzeff; Adam R. Lawrence; Justin Lajoie; Travis R. Sippel; Lori J. Groven

Composite solid propellant consisting of hydroxyl-terminated polybutadiene (HTPB) and ammonium perchlorate (AP) has been the workhorse for solid rocket propulsion for the past several decades. To enhance the performance of the propellant, catalysts and/or fuels are often added. However, catalysts do not contribute to the overall reaction, and fuels such as aluminum can lead to agglomeration, which negatively influences performance. Thus, an additive that serves as both fuel and a catalyst is of interest. Magnesium diboride (MgB₂) has been investigated to act as this synergistic fuel and catalyst. In this effort, we report the influence of MgB₂ on the combustion properties of a composite propellant. The thermal decomposition, pressurized burning rate, and calculated performance were investigated as a function of MgB₂ loading. The thermal decomposition events were reduced by 23°C and 27°C at 15 wt% MgB₂ compared to the neat propellant. Thermochemical calculations indicate that the specific impulse is maximized at 16 wt% MgB₂, at 241 s, while the adiabatic flame temperature reaches its maximum at 2382 K at 18 wt%. Pressurized burning rates reveal that as the MgB₂ content increases, the burning rate and pressure sensitivity generally increase, likely due to additional heat feedback from the emissive metal species. This work presents the influence of MgB₂ on both catalytic and combustion performance, demonstrating its potential to serve as a synergistic fuel and catalyst in composite propellant.