FORMATION OF ALUMINUM NANOPOWDERS AND THEIR APPLICATION IN NANOENERGETIC MATERIALS Dr. Jan A. Puszynski Chemistry and Chemical Engineering Department South Dakota School of Mines & Technology Rapid City, SD Tel: 605/ Fax: 605/

PARAMETRIC STUDIES: FORMATION OF ALUMINUM NANOPOWDERS 100 nm 1.5 nm

Mathematical Modeling of Aerosol Dynamics

Stages in Particle Formation

Modeling the Aerosol Dynamics The rate of change of various moments of the aerosol size distribution for the n th cell can be written by : First Moment, M 1 Aerosol Surface Area, A Aerosol Number Density, N

Modeling the Aerosol Dynamics d 1, s 1, v 1 are the monomer diameter, surface area and volume respectively. The saturation ratio S is given by: The nucleation rate I is given by:

Schematic Representation of Cascade Flow Model

Modeling the Aerosol Dynamics In the case of several CSTAGs (Continuous Stirred Tank Aerosol Generator) in series, the governing mass balance equation is given by:

2-D Temperature Profiles in the Al Nano-Powder Generator (P He =5Tr)

2-D Temperature Profiles in the Al Nano-Powder Generator (P Ar =5Tr)

Axial Temperature Profiles in the Generator for Helium and Argon

Median Particle Diameter vs. Inert Gas Pressure

Characterization of uncoated and coated aluminum nanopowders. DETERMINATION OF REACTIVE ALUMINUM CONTENT Thermogravimetric method (TGA) Volumetric method (VM) Bomb calorimetry method (BCM)

TGA of Aluminum Nanopowders wt % of reactive aluminum wt % of reactive aluminum

Comparison of TGA, Volumetric, and Bomb Calorimetry Methods Aluminum Average Particle Size TGA Method wt% Volumetric Method wt% Bomb Calorimetry wt% 50 nm nm  m

Surface Functionalization of Al Nanopowders And Their Reactivity with Moisture and Liquid Water Mixing Processing Long-term stability

Effect of Moisture on Aluminum Nanopowders

Effect of Moisture (97% RH) on Coated and Uncoated Aluminum Nanopowders

Ageing of Aluminum Nanopowders in Liquid Water

Ageing of Aluminum Nanopowders 97% RH and 40 o C Aged 0 hrs, 74 wt% reactive Al Aged 40 hrs, 59 wt% reactive Al

Ageing of Aluminum Nanopowders Aged 60 hrs (97% RH), 17 wt% reactive Al Aged 80 hrs (97% RH), 0 wt% reactive Al

Aluminum Nanopowder Coated with 4 wt% of Silane

DISPERSION AND MIXING OF NANO-POWDERS

Sedimentation of Aluminum Nano-powder in Hexane Time: 30 secTime: 50 sec Without dispersant Time: 5 minTime: 30 min J With dispersant (2 wt% sodium dioctyl sulfosuccinate, SDS)

Characterization of Mixing Quality of Binary Nano-powders (high resolution) Wet Mixing of Al(red) / TiO 2 (blue) System (with SDS dispersant): SE/Cameo Image 50,000X SE/BSE/Element Mapping 50,000X SE/Element Line Scan 50,000X

Al-TiO 2 -mixture prepared in absolute ethanol with sodium dioctyl sulfosuccinate as surfactant. Sample after three line scans of 10  m at X.

Dry mixing Wet mixing hexane Wet mixing ethanol(w/disp.) Wet mixing hexane (w /disp.) Mixing Index A K,L for different samples Mixing Index for the Mixtures of Nanosized Powders

INVESTIGATION OF COMBUSTION CHARACTERISTICS IN SYSTEMS CONTAINING ALUMINUM AND METAL OXIDES NANOPOWDERS

REACTIONT ad [K]  [kg/m 3 ] 2Al + MoO 3 3, Al + 3MnO 2 2, Al + 3I 2 O 5 >3, Al + 3CuO2, Al + WO 3 3, Al + Fe 2 O 3 3, Al + Bi 2 O 3 3, Adiabatic Temperature of Energetic Reacting Systems

Schematics of the Burn Test Equipment

Reacting System: Nanosize Al (40 nm) and Nanosize Fe 2 O 3 (Nanophase Technologies, Corp.) Combustion Front Velocity: 30 m/s Recording Speed: 8000 frames/sec Playback Rate: 30 frames/sec t= 0.1 t= 200 t= 600 t= 800 t= 100 t= 300 t= 500

Reacting System: Nanosize Al (50 nm NSWC/IH) and Micronsize MoO 3 (Climax Molybdenum Company) With Perforated Baffles t= 0.1 t= 100 t= 170 t= 200 t= 50 t= 150 t= 160

Effect of Coating on Combustion Front Velocity Under Unconfined Conditions

Wt% of Coating Effect of Coating on Ignition Delay Time

Effect of Average Particle Size of Aluminum on Burn Rate in Al-CuO System

Schematics of the pressure vessel equipment

Equipment for Burn test of Aluminum under confined conditions CAMERA REACTOR AUTO TRANSFORMER VACUUM PUMP VENT GAS INLET DATA ACQUISITION SYSTEM PRESSURE GAUGE THERMOCOUPLE WIRES SAFETY VALVE FLANGE 1 FLANGE 2 Reactor Alumin Boat LEADS FROM THERMOCOUPLE TO DATA AQUISITION MOLYBDENUM IGNITION WIRE Aluminum loose powder Pressure Vessel Experimental Set-up

Pressure Responses in Al (uncoated)-CuO System IDT Pmax

Wt% of Coating Effect of Coating on Ignition Delay Time

New experimental technique: Recoil force measurement during unconfined burn of a nanoenergetic mixture. Load cell (force transducer) : Entran Devices, Inc. Linear range: 0 – 1000 N Sensitivity : ~200 mV/1000 N

Average recoil force during combustion of the MICs