Pyrophoric Nanoparticles and Nanoporous Foils for Defense Applications
Abstract
The formation of pyrophoric Fe-nanoparticles and foils from Fe(II)-oxalate and Fe-oxyhydroxide gel was investigated after thermal decomposition and reduction under H2 atmosphere. The Fe(II)-oxalate was synthesized by a controlled nucleation process involving the addition of oxalic acid in an FeC12 .2H2O solution followed by separation and drying. The gel was synthesized using the Fe(II) salt, non-ionic surfactant, and propylene oxide. Oxalate powder was sandwiched between two mesoporous Y2O3 barrier layers on a metal foil, whereas the Fe-oxyhydroxide gel was coated directly on a foil to prepare the reactive substrates. In other experiments, the gel was infiltrated inside a porous alumina substrate. Assynthesized reactive materials were decomposed in a quartz tubular reactor at 450-520 deg C, reduced with a gas mixtures containing 5-100 vol% of H2 in N2, and exposed to air at ambient conditions to determine their pyrophoric properties. The bulk powder and foils prepared from Feoxalate produced a pyrophoric reaction temperature of about 800 deg C in less than 1 sec. The porous substrates containing reduced Fe from the gel produced a pyrophoric temperature above 900 deg C. Tunable pyrophoric materials were obtained by mixing Fe-oxalate in different weight proportions in the Y2O3 gels, which showed a variation in pyrophoric reaction temperature from 80 deg to 600 deg C at the weight ratio of 30-80%.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 2008
- Accession Number
- ADA505824
Entities
People
- Alok Vats
- Chris Haines
- Darold Martin
- Deepak Kapoor
- Jan Puszynski
- Rajesh Shende
- Zac Doorenbos
Organizations
- South Dakota School of Mines and Technology