Investigations of the small-scale thermal behavior of sol-gel thermites.
Abstract
Sol-gel thermites, formulated from nanoporous oxides and dispersed fuel particles, may provide materials useful for small-scale, intense thermal sources, but understanding the factors affecting performance is critical prior to use. Work was conducted on understanding the synthesis conditions, thermal treatments, and additives that lead to different performance characteristics in iron oxide sol-gel thermites. Additionally, the safety properties of sol-gel thermites were investigated, especially those related to air sensitivity. Sol-gel thermites were synthesized using a variety of different techniques and there appear to be many viable routes to relatively equivalent thermites. These thermites were subjected to several different thermal treatments under argon in a differential scanning calorimeter, and it was shown that a 65 C hold for up to 200 minutes was effective for the removal of residual solvent, thus preventing boiling during the final thermal activation step. Vacuum-drying prior to this heating was shown to be even more effective at removing residual solvent. The addition of aluminum and molybdenum trioxide (MoO{sub 3}) reduced the total heat release per unit mass upon exposure to air, probably due to a decrease in the amount of reduced iron oxide species in the thermite. For the thermal activation step of heat treatment, three differentmore »
- Authors:
- Publication Date:
- Research Org.:
- Sandia National Laboratories (SNL), Albuquerque, NM, and Livermore, CA (United States)
- Sponsoring Org.:
- USDOE
- OSTI Identifier:
- 947823
- Report Number(s):
- SAND2009-0705
TRN: US0901557
- DOE Contract Number:
- AC04-94AL85000
- Resource Type:
- Technical Report
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 22 GENERAL STUDIES OF NUCLEAR REACTORS; ADDITIVES; ALUMINIUM; ARGON; BOILING; FUEL PARTICLES; HEAT TREATMENTS; HEATING; IGNITION; IRON OXIDES; MIXTURES; MOLYBDENUM; OXIDES; REMOVAL; SAFETY; SENSITIVITY; SYNTHESIS; THIN FILMS; TUNGSTEN; Explosives.; Thermal diffusivity.; Thermite.
Citation Formats
Warren, Mial E, Farrow, Matthew, and Tappan, Alexander Smith. Investigations of the small-scale thermal behavior of sol-gel thermites.. United States: N. p., 2009.
Web. doi:10.2172/947823.
Warren, Mial E, Farrow, Matthew, & Tappan, Alexander Smith. Investigations of the small-scale thermal behavior of sol-gel thermites.. United States. https://doi.org/10.2172/947823
Warren, Mial E, Farrow, Matthew, and Tappan, Alexander Smith. 2009.
"Investigations of the small-scale thermal behavior of sol-gel thermites.". United States. https://doi.org/10.2172/947823. https://www.osti.gov/servlets/purl/947823.
@article{osti_947823,
title = {Investigations of the small-scale thermal behavior of sol-gel thermites.},
author = {Warren, Mial E and Farrow, Matthew and Tappan, Alexander Smith},
abstractNote = {Sol-gel thermites, formulated from nanoporous oxides and dispersed fuel particles, may provide materials useful for small-scale, intense thermal sources, but understanding the factors affecting performance is critical prior to use. Work was conducted on understanding the synthesis conditions, thermal treatments, and additives that lead to different performance characteristics in iron oxide sol-gel thermites. Additionally, the safety properties of sol-gel thermites were investigated, especially those related to air sensitivity. Sol-gel thermites were synthesized using a variety of different techniques and there appear to be many viable routes to relatively equivalent thermites. These thermites were subjected to several different thermal treatments under argon in a differential scanning calorimeter, and it was shown that a 65 C hold for up to 200 minutes was effective for the removal of residual solvent, thus preventing boiling during the final thermal activation step. Vacuum-drying prior to this heating was shown to be even more effective at removing residual solvent. The addition of aluminum and molybdenum trioxide (MoO{sub 3}) reduced the total heat release per unit mass upon exposure to air, probably due to a decrease in the amount of reduced iron oxide species in the thermite. For the thermal activation step of heat treatment, three different temperatures were investigated. Thermal activation at 200 C resulted in increased ignition sensitivity over thermal activation at 232 C, and thermal activation at 300 C resulted in non-ignitable material. Non-sol-gel iron oxide did not exhibit any of the air-sensitivity observed in sol-gel iron oxide. In the DSC experiments, no bulk ignition of sol-gel thermites was observed upon exposure to air after thermal activation in argon; however ignition did occur when the material was heated in air after thermal treatment. In larger-scale experiments, up to a few hundred milligrams, no ignition was observed upon exposure to air after thermal activation in vacuum; however ignition by resistively-heated tungsten wire was possible. Thin films of thermite were fabricated using a dispersed mixture of aluminum and iron oxide particles, but ignition and propagation of these films was difficult. The only ignition and propagation observed was in a preheated sample.},
doi = {10.2172/947823},
url = {https://www.osti.gov/biblio/947823},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Feb 01 00:00:00 EST 2009},
month = {Sun Feb 01 00:00:00 EST 2009}
}