Paper TF-ThA4
Combustion Characterization of Blade Cast Magnesium and Manganese Dioxide

Thursday, October 31, 2013, 3:00 pm, Room 102 C

There is a current need for low cost heat sources for a variety of applications, from local joining and welding, to providing local heat for power sources. In this work, powders of magnesium and manganese oxide were mixed with a fluorpolymer or paraffin binder and blade cast onto a stainless steel foil substrate. The three binder-solvent systems investigated were Methyl Pyrrolidone (NMP) and Polyvinylidene Fluoride (PVDF), Acet one and Viton A, as well as Paraffin and Xylene. Films were prepared by mixing the energetic composites with the binder and solvent to create a 40% solids content suspension, and then casting onto stainless steel foil to a 200um wet film thickness. In this study, binder content and type was varied, and calorific output and open flame propagation speed was investigated for each mixture ratio. It was found that calorific output increased with increasing binder content, to a maximum observed value of 954 calories per gram, indicating participation of the binder in the exothermic reaction. Flame speed was shown to decrease with increasing binder content, with a maximum recorded value of 0.14 m/s for unconfined tests. This may reflect the lower heat transfer of the binder, or some mechanism that blocks propagation with increasing binder content. Confined tests were also conducted for the PVDF/NMP system, with a maximum recorded flame speed of 3.46 m/s. High speed video of the flame propagation shows significant gas generation ahead of the flame front, which may explain the observed difference between confined and open burn speeds, as the ejecta plume preheats the material in advance of the flame front.