Ignition in Al-Fe 2 O 3 Nanocomposites
- PDF / 251,082 Bytes
- 4 Pages / 612 x 792 pts (letter) Page_size
- 51 Downloads / 243 Views
0901-Ra11-16-Rb11-16.1
Ignition in Al-Fe2O3 Nanocomposites L. Menon, K. Bhargava Ram1, S. Patibandla1, C. Richter2 and A. Sacco, Jr2. Physics, Northeastern University, Boston, MA 02115 2 Chemical Engineering, Northeastern University, Boston, MA 02115 3 Electrical Engineering, Virginia Commonwealth University, Richmond, VA 23284 ABSTRACT We demonstrated a novel approach to fabricate a self-assembled array of energetic nanocomposites which undergo an exothermic reaction at high temperature. The nanocomposites are a mixture of fuel and oxidizer materials where one of the components (fuel or oxidizer) is in the form of an array of nanowires embedded in the other component (oxidizer or fuel) which is in the form of a thin film. Our fabrication approach allows for a very high packing density of the nanocomposites, precise control of oxidizer-fuel sizes at the nanoscale level and intimate mechanical contact between oxidizer and fuel. Such nanocomposites will have important applications in novel energetic devices, for example MEMS-based fuzes, nanoexplosives and in applications requiring light-weight, single-use energy sources. INTRODUCTION Recently, we demonstrated a new kind of nanocomposite material, which exhibits ignition at moderate temperatures [1]. The material is a mixture of oxidizer and fuel material and is in the form of a nanowire array-based thin film. Fe2O3 (oxidizer) is in the form of nanowires embedded vertically in a thin Al (fuel) film. The unique features of our nanocomposites are their highly structured nature and tight packing, precisely controlled oxidizer-fuel sizes and positions at the nanometer scale, and intimate mechanical contact between oxidizer and fuel components. Such nanocomposites have several potential applications in energy sources, MEMS-based energetic devices, etc. More importantly, our samples are model systems in which we can study fundamental properties of energetic phenomena at the nanoscale level. EXPERIMENTAL RESULTS AND DISCUSSIONS A brief description of the fabrication procedure of our nanocomposite material is given here. More details can be found in ref [1]. First, Fe nanowires, are created in a regular array by means of electrodeposition inside nanoporous alumina membranes. These are aluminum oxide membranes consisting of an array of cylindrical nanosized holes. Such membranes are prepared electrochemically in our laboratory using a dc anodization technique. Electrodeposition of Fe is followed by several processing steps, including wet and dry etching, annealing and thin film deposition techniques to create the final product, namely Al film attached to an array of Fe2O3 nanowires [1,2]. A typical cross-section scanning electron microscopy (SEM) image of the final product is shown in Fig. 1. In the image, the diameter of a single nanowire is about 50 nm and the density of nanowires for all observed specimens is 1010 wires/cm2 with a surface fill factor of 0.2. In our fabrication approach, the size of fuel and oxidizer can be easily controlled. The smallest achievable wire di
Data Loading...
