Improving the burn-rate of thermite reactions using mesoporous copper-oxide and aluminum nano-particles [abstract]

Abstract only availableEnergetic materials are defined as substances in which fuel and oxidizer react to release energy. The amount and rate of energy released by this reaction can be improved by increasing the amount of interfacial contact between fuel and oxidizer. Using a surfactant templating method a mesoporous copper oxide material was prepared. The copper oxide was then mixed with a fuel composed of aluminum nano-particles (80nm) to create an energetic material. When reacted, the burn rate for the self propagating reaction was higher than that of any previously known energetic material. Further improvement can be made by ordering the arrangement of pores, using surfactant templating. In this method surfactant is introduced into a colloidal suspension called sol that will eventually form the copper-oxide gel. Due to the lyphobic and lyophilic interactions in the solution, the surfactant molecules form ordered miceller structure. Using various methods the surfactant can then be removed leaving an ordered network of empty pores in the copper oxide material. When combined with the aluminum nanoparticles, the fuel fills in these pores creating an ordered network of fuel filled pores, greatly increases the amount of interfacial contact between fuel and oxidizer as well as the performance. Although this method has been shown to dramatically improve the performance of this material its applications have been limited by its costs. The primary precursor used in preparing mesoporous copper oxide is copper ethoxide which is extremely costly. The precursor alone cost well over $1600 for every 100g of material prepared. However it has recently been found that similar results can be achieved using much less expensive CuCl2 as a precursor. This material promises to reduce the precursor cost to around$26 per 100g of material produced and greatly expand the number of applications for which this material is suited.Discovery Fellowship Progra

Generation of fast propagating combustion and shock waves with copper oxide/aluminum nanothermite composites

doi:10.1063/1.2787972Nanothermite composites containing metallic fuel and inorganic oxidizer are gaining importance due to their outstanding combustion characteristics. In this paper, the combustion behaviors of copper oxide/aluminum nanothermites are discussed. CuO nanorods were synthesized using the surfactant-templating method, then mixed or self-assembled with Al nanoparticles. This nanoscale mixing resulted in a large interfacial contact area between fuel and oxidizer. As a result, the reaction of the low density nanothermite composite leads to a fast propagating combustion, generating shock waves with Mach numbers up to 3.We gratefully acknowledge the financial support by U.S. Army, ARDEC, New Jersey and National Science Foundation

Erratum: “Generation of fast propagating combustion and shock waves with copper oxide/aluminum nanothermite composites” [ Appl. Phys. Lett. 91, 243109 (2007) ]

doi:10.1063/1.2938420 Related to http://hdl.handle.net/10355/8197 and to http://hdl.handle.net/10355/8198Another erratum concerning “Generation of fast propagating combustion and shock waves with copper oxide/aluminum nanothermite composites” [ Appl. Phys. Lett. 91, 243109 (2007) ]

Nano-synthesis of Energetic Materials [abstract]

Abstract only availableEnergetic materials are defined as substances in which fuel and oxidizer react chemically to release energy. The amount and rate of energy released by this reaction can be improved by increasing the amount of interfacial contact between fuel and oxidizer. In conventional energetic materials macroscopic particles of fuel and oxidizer are mixed randomly. In this arrangement energy is lost due decreased contact between fuel and oxidizer as a result of the large particle size and random distribution. To reduce the amount of energy lost much smaller nano-particles can be used. The smaller particles allow for increased interfacial contact between fuel and oxidizer, resulting in improved performance. Even with smaller particles some energy is still lost due to the random arrangement. In order to further improve performance it is necessary to order the arrangement of fuel and oxidizer. Utilizing a method known as surfactant templating ordered structures such as nanorods, nanowires, and nanowells (similar to a honeycomb) can be created from oxide materials such as Copper Oxide, and Iron Oxide. When Aluminum Nano-particle fuel is mixed with these ordered oxide materials the resulting material has greatly increased interfacial contact between fuel and oxidizer. When reacted, these materials have minimal energy loss and greatly improved energetic performance. The increased performance of this type of material has created the possibility of many new applications for energetic materials. The potential uses for this material range from on chip power generation, to shockwave generation for medical imaging.College of Engineering Undergraduate Research Optio

Electric arc production of nanoparticles for energetic materials [abstract]

Abstract only availableThermites are a class of energetic material (similar to explosives) which consists of a fuel and oxidizer which react chemically to release energy. These materials are of interest because they can contain over 2.5 times more energy than TNT and they can be made from relatively benign components. The rate at which these materials react depends on the size of the fuel and oxidizer particles. Traditionally prepared thermites have relatively large particle sizes and therefore tend to react slowly. We are producing a new type of thermite called super-thermite which uses very small particles known as nanoparticles. These small particles of fuel and oxidizer react much more quickly than traditionally prepared thermites. Using this method we can prepare super-thermites which burn at over 2,000 meters/second. These properties make super-thermite an ideal replacement for several toxic lead containing energetic materials. However, super-thermite materials are currently too expensive for most applications. We are researching several new methods of preparing nanoparticles for super-thermite which will reduce their cost. One method we are using is called plasma arc-discharge, and actually very similar to an arc welding process. In arc welding electricity is used to form plasma arc. The heat from the arc melts the metals and fuses them together. In our process we continue to heat the material until it evaporates and forms a vapor. When the vapor cools it condenses forming nanoparticles. This process has been used previously to prepare nanoparticles of aluminum, silicon, and copper oxide. In the near future we will extend this method to other materials as well. The benefit of this method is nanoparticles can be prepared from relatively affordable bulk materials. Using this method we hope reduce the cost of preparing super-thermite from over $20.00/gram to less than$0.25 per gramCollege of Engineering Undergraduate Research Optio