Metal-based reactive nanomaterials

Metal-based nanoenergetic materials: Synthesis, properties, and applications

Catalytic effects of nano additives on decomposition and combustion of RDX-, HMX-, and AP-based energetic compositions

Highly stable aluminum nanoparticles (NPs) are generated via ablation of bulk Al in ethanol using either femtosecond (fs) or picosecond (ps) laser sources. The colloidal NPs solutions obtained with fs pulses exhibit a yellow coloration and show an increased optical absorption between 300 and 400 nm, tentatively assigned to the plasmon resonance of nanosized Al. The corresponding solutions after ps ablation are gray colored and opalescent. The average size of the NPs formed ranges from 20 nm for the fs case to 60 nm for the ps case, while a narrower distribution is obtained using the shorter pulses. High Resolution Transmission Electron Microscopy (HRTEM) studies indicate that the NPs are mostly amorphous with single crystalline inclusions. Al NPs generated with short laser pulses slowly react with air oxygen due to the presence of a native oxide cladding, which efficiently passivates their surface against further oxidation.

Generation of Al nanoparticles via ablation of bulk Al in liquids with short laser pulses

A compressive review on the effects of alcohols and nanoparticles as an oxygenated enhancer in compression ignition engine

The characterization of several differently sized aluminium powders, by BET (specific surface), EM (electron microscopy), XRD (x-ray diffraction), and XPS (x-ray photoelectron spectroscopy), was performed in order to evaluate their application in solid rocket propellant compositions. These aluminium powders were used in manufacturing several laboratory composite solid rocket propellants, based on ammonium perchlorate (AP) as oxidizer and hydroxil-terminated polybutadiene (HTPB) as binder. The reference formulation was an AP/HTPB/Al composition with 68/17/15% mass fractions respectively. The ballistic characterization of the propellants, in terms of steady burning rates, shows better performance for propellant compositions employing nano-aluminium when compared to micro-aluminium. Results obtained in the pressure range 1-70 bar show that by increasing the nano-Al mass fraction or decreasing the nano-Al size, larger steady burning rates are measured with essentially the same pressure sensitivity.

http://iopscience.iop.org/article/10.1088/0953-8984/18/33/S15/pdf

Nanoparticles for solid rocket propulsion

Carbon Nanotubes (CN) form a new class of materials that has attracted large interest in the scientific community because of their extraordinary properties (mechanical, electrical, thermal, etc.), as well as owing to the diversity of the proposed technological applications. The characterization of CN is the result of specific sample preparation procedures and requires the use of selected tools (e.g. SEM, HRTEM, EDX, Micro Raman, AFM, STM). We report some studies we carried out based on the CN characterization with the Atomic Force Microscopy (AFM). The general characteristics of the AFM employed and the sample preparation methods are illustrated. The research activities are focused on the development of specific analysis procedures. In fact, the interaction forces between the AFM cantilever tip and the sample, is the main parameter in the acquisition of a 3D topographic AFM micrograph.

https://iopscience.iop.org/article/10.1088/1742-6596/61/1/021/pdf

Atomic Force Microscopy Characterization of Carbon Nanotubes

Electrical and mechanical properties of composite materials based on Carbon Nanotubes are considered for aerospace applications. Nanostructured materials gained great importance in the past decade, owing to their wide ranging potential applications in many areas, e.g. mechanical, structural, sensor, biomedical, electronics. Of particular interest are carbon nanotubes, which can be used as a main constituent of composite materials with exceptional mechanical and electrical properties, very suitable for aerospace applications, also due to their light weight, mechanical strength and flexibility. We present results obtained recently in our laboratories concerning the electrical and mechanical properties (including resilience measurement, stress analysis, conductivity) of carbon nanotubes we synthesized by arc discharge and other techniques, embedded in a polymer matrix.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Composite materials based on Carbon Nanotubes for aerospace applications

Carbon nanotubes (CNT) were synthesized by DC thermal plasma method. After optimizing the synthesis parameters like the pressure, current etc., the synthesized products especially the anodic deposit was characterized by electron microscopies like Scanning Electron and Transmission Electron microscopies. The morphology of the product was ascertained to be multiwalled carbon nanotubes in large ratio. The diameters of these nanotubes were of the order of 30 – 50 nm and the lengths extending upto a micron and sometimes even 2 or 3 microns. These nanotubes were then studied for its field emission properties. The CNTs were deposited on a metal stub which acted as the cathode. Care was taken to ensure complete covering of the stub to remove any possibility of emission from the metallic stub itself. The emission studies were performed in a stainless steel chamber under a dynamic vacuum in the range of 10 -8 torr. The field emitted current was detected using a phosphor coated ITO (Indium tin oxide) glass. The phosphorous coating also helped in imaging the tips of the nanotubes. This was crucial in estimating accurately the emitting area and thus the field enhancement factor. The I-V curves for the field emission were recorded for various distances between the electrodes. These results will be shown in the presentation.

/pdf/study-of-field-emission-of-multiwalled-c-nanotubes-from-arc-1v59xvabvw.pdf

Study of field emission of multiwalled C nanotubes from arc discharge


An innovative recycling process for thermoset composite laminates is proposed by thermo-mechanical disassembly and further compression molding of hybrid thermoformable composite plates. Due to the thermo-mechanical process, single cured plies are extracted from the waste laminate. Subsequently re-lamination is performed by interposing thermoplastic films between the reclaimed composite plies. Final consolidation is carried out by compression molding. In order to show the feasibility of the novel recycling technology, carbon fiber reinforced composite plates by autoclave molding were thermo-mechanically disassembled in a manual roll bending machine after heating in oven. Reclaimed cured plies were laminated by alternating thermoplastic interlayers made of low density polyethylene. The hybrid laminate was consolidated at the temperature of 220�C and the holding pressure of 38.5 bar. Results from bending tests on virgin and recycled plates showed the very good agglomeration of the hybrid samples and the optimal preservation of performances of initial cured plies of the virgin material into the recycled plate.


/pdf/recycling-of-carbon-fiber-laminates-by-thermo-mechanical-3ak33uo0.pdf

M. Regi

Papers

Nanoparticles for solid rocket propulsion

Atomic Force Microscopy Characterization of Carbon Nanotubes

Composite materials based on Carbon Nanotubes for aerospace applications

Study of field emission of multiwalled C nanotubes from arc discharge

Recycling of Carbon Fiber Laminates by Thermo-mechanical Disassembly and Hybrid Panel Compression Molding