Green-Flame Metal Oxide Synthesis
Laboratory synthesis of the target green-flame metal oxides began using standard chemical precursor materials. Initial batch yields were acceptable, but quality control testing revealed significant purity issues. Chemical analysis showed 10-15% contamination from precursor materials and synthesis byproducts not removed during workup procedures.
Contamination Sources and Effects
Detailed analysis identified multiple contamination sources: residual precursor compounds, intermediate oxidation products, and trace metals from reaction vessels. These impurities altered combustion behavior in unpredictable ways. Batches with different contamination profiles showed widely varying specific impulse values, ranging from 180 to 240 seconds for nominally identical formulations. Flame color also varied with impurity content, from pale yellow-green to deep green.
Batch-to-Batch Variability
The high level of contamination created severe batch-to-batch variability, making it impossible to establish reproducible propellant specifications. Small changes in synthesis procedure or precursor purity led to significantly different final product properties. This variability is unacceptable for any propulsion application and represents a fundamental barrier to development.
Purification Development
Laboratory work is focused on developing purification procedures to achieve 99%+ purity in the final product. Multiple purification strategies are being evaluated: recrystallization, selective precipitation, and high-temperature annealing. Initial purification tests show promise but require optimization. Synthesis procedure modifications are also underway to reduce contamination formation during the reaction. Achieving consistent, high-purity batches is critical for program advancement.