Combustion Analysis Of Nanoenergetic Materials

NEEM MURIARO Final Review of "A Unified Multiscale Approach for NanoEngineered Energetic Materials,” Heat Center, Aberdeen, Maryland,15 March 2010Combustion Analysis ofNanoenergetic MaterialsRichard Yetter, Jongguen Lee, Mike Weismiller,Justin Sabourin, Steven Dean, and Bruce YangThe Pennsylvania State UniversityTim Foley, Blaine Asay(L Alamos(LosAlNNationaltilLLaboratory)b t )Steven F. Son (Purdue University)Tim Eden, Orlando Cabarcos, Dave Allara (PennState)

NEEM MURIResearch Areas Flame spread across thin fuel films of nano metallic particles. Combustion of nAl with O2/Ar mixtures – unified theory developed. Combustion of nAl with CO2, CO,CO N2O,O and N2. Combustion of nano metallic particles and flame propagation throughquasi-homogeneous mixtures of nano metallic particles and liquid andgaseous oxidizers. Combustion of nAl/liquid H2O Combustion of nAl/H2O/H2O2 Combustion of nAl/CH3NO2 Combustion of nB/CH3NO2 Combustion of nano metallic particles and flame propagation throughquasi-homogeneous mixtures of nano metallic particles and solid oxidizers. Combustion of nano Al/MoO3 thermites – stoichiometry and channelsize. Combustion of nano Al/CuO thermites –fuel particle size, density, anddil tion effects.dilutioneffects Combustion of nB in Al/CuO thermites. Self-assembly of ordered microspheres of a nanoscale thermite.

NEEM MURIResearch Areas Liquid propellants with nanostructured additivesand nano aluminum gelled propellantspropellants. Temperature, pressure, and oxidizer particle effectson nanothermitesnanothermites. Nano intermetallic powder systems.

NEEM MURISelf-Assembled NanoscaleThermite MicrospheresOpal gem: organized nanoparticle self assemblySanders, J. V., Murray, M. J., Nature v275, 1978.Laboratory assembled nAu & nAg compositesKalsin et al., Science, v312, 2006Structure of the Abalone Shell (A reactive material structure?)A. Lin and A. Meyers, Mat. Sci. Eng. A 390, 27-41, 2005.inorganico ga c layers:aye s ((inter-metallicteeta c fuelue layers?)aye s )organic layers: (energetic binder layers?) Create Self‐Assembled Monolayer (SAM) on surface of particles Monolayers contain a functionalized group at tail end (either or– charged) When mixed in a diluted and elevated temperature they formenergetic macroscale structures with nanoscale yl) Malchi, J., Foley,T., Yetter, R.A., Reactive Compositepammonium chloride)nAl (38nm)ACS APPLIED MATERIALS &INTERFACES, 2009nCuO‐MUAnCuO(33nm)(11‐mercaptoundecanoic acid ) 4 μm

NEEM MURINanostructured Additives forEnhanced Propellant CombustionAluminummonohydroxideGraphene3.5Neat NM;5.23 MPa,rb 1.2 mm/sNM 00.39%39% (mass)SiO2 gel; 5.25 MPa,rb 1.9 mm/s2 s steps, under ArgonNM 0.3% (mass)FGS22; 5.16 MPa,rb 2.2 mm/sPchamber 5.24 /- 0.05 MPa3Linear Burning Rate, mm//sNM 0.5% (mass)AlOOH; 5.16 MPa,rb 1.6 mm/sSilicaFGSAl O Plus22.53Porous SiO221.5r , neatt NM 11.2020 mm/s/b100.10.20.30.4Concentration, volume %0.50.6

NEEM MURICombustion of Nano AluminumGelled Propellants

NEEM MURIWhen ignited in a burntube, ‘fast’ nanothermites(Al/C O Al/M(Al/CuO,Al/MoOO 3,Al/Bi2O3) react through aconvective mechanismConvective burning isdriven by the creation ofa large pressure gradientin the porous mixture,and not by a temperaturegradientPressureTransducersFiber OpticCablesPropagation Mechanisms ofNanothermite ReactionsConvection wavePPressureGradientdrivesgasesforward forwardPressuregradientdrivesreactionHeat ConductionHot gasespenetrate theFlame Zone granular mixturePorousReactantsTemp ardforwardThPowder –FilledTubeT0

2 Al 3CuO Al2O3 3Cu1000HeVf[m/ss]f510P 0510P [MPa]a1510 1 m/sSlow Constannt VelocityOscillating100V [m/s]]V [m/s]]N210010010Oscillating10001000Ar10100’s m/sPressure (MPa)Acceelerating As pressure is increased, several different modes ofpropagation are observedPPressureatt whichhi h propagationti moded changeshddependsd onpressurizing gas; He has a high thermal conductivityVf (m//s) AcceleraatingNano-aluminum from Novacentrix (avg. dp 38nm) Nano CuO from Sigma-Aldrich (avg. dp 33nm) Studies conducted in an optical strand burner (V 23 liters) Pressurized with 3 differentffgases (Ar,(He, or N2) 1 kmm/sEffect of Pressure on the PropagationRate in a Al/CuO NanothermiteFast Constannt VelocityNEEM MURI510P [MPa]a15

NEEM MURIPrevious work: gas fraction at equilibriumDrawbacks: No intermediate gases (not present at equilibrium) Many of the equilibrium gases will not be realized untilvery high temperatures (ex. Cu: BP of 2835K)30Preessure [MPa]nAl/MoO3Temperature Measurements forunderstanding Gas GenerationnAl/MoO3nAl/CuO in burn tube at1atm in air2010000.0005Time [s]0.001The measured over-pressures (in excess of 10 [MPa])can only be explained by gas generation N genP1 R T2 P1ΔP Vint R T1 Generation ofgaseous speciesHeating ofinterstitial gas

NEEM MURIOptical TemperatureMeasurementsTime integrated temperaturemeasurement set-upPile of energeticthemite to be sampledTemporally resolved temperaturemeasurements via streak cameraHigh Speed CameraOptical fiberImage ProcessorSpark igniter CLSpark Igniter-SignalGeneratorCCD CameraThermite-FilledBurn TubeOutput OpticsExternal TriggerSignalGeneratorStreakCamera(C7700-01)Input OpticsOptical fiberData AcquisitionComputerpOcean Optics HR2000SpectrometerpCoupling lens Spectrograph

NEEM MURI Optical Pyrometry requires considerationof Material Spectral EmissivityIn general:ε ε (λ , T )Simplest Solution:ε const.Two-color pyrometryMore Accurate Solution:Assume emissivity has a knownrelationship with λ ( ε λn )Planck’s LawE (T , λ ) ε (λ , T ) C1λ [nm] C2 λT 1 λ e 5C3λε λλ-22 andd ε const,t alsol consideredid dCurve Fitting Equation [used by Ng et al Review of ScientificInstruments (2001)] C CZ Ln 61 E (λ , T ) 2 Ln(C 3 ) λ T λ161000667500y 6.06961E-06x 5.0513T 2370 KZε (λ ) 1814121E 61.5E 6-11/λ [m ]2E 6

Temperature Measurements Suggestthat the Final Products are not Gasified500Al BPAl boiling pointt321000Al O boiling pointAlBP2O3 B1500Cu boiling PointCuBP2000Measured2500Measured TemperaturreBurn Tube Propagationp gRate 1 km/sCombustion Temperature 2350 150 K3000Equilibrum TempeeratureEquilibrium2 Al 3CuO Al2O3 3CuAl/CuO3500TemperatuureTemperature[K] (K)NEEM MURI02000150010005000Al/F 2O3Al/Fe5000Al/Fe2O3Al BBP32Al boiling point1000Fe 2500boilingpointAlAl2 O3 OBP3000EquilibrrumEquilibrriumTemperaatureBurn Tube Propagation Rate 0.1 m/sCombustion Temperature 1700 150 KAl/MoO33500Tempperature(K)Tempperature [K]2 Al Fe 2 O 3 Al 2 O 3 2 FeAlAl perature3500Al2 O int4500EquilibriiumTemperatuureBurn Tube Propagation Rate 1 km/sp 2150 150 KCombustion TemperatureTempeerature(K)Tempeerature [K]2 Al MoO3 Al 2O3 MoAl/CuO5000

NEEM MURIMetal Oxides Vaporize orDecompose at Low 1750MoO310751428n/aCu1210Volume28OCu O 00 2000 3000 4000 5000Temperature [K]13Fe2O3 2Fe3O4 O221 10FeO (l)4800010Fe O (s)8260003Volum e6Fe O (s)34O2040O210002000Tem perature [K ]321412CuO Cu2O O22V [cm[/g]Cu O (l)8000V [cm /g]ConcentrationCn [mol/kg]14ConcentrationCn [mol/kg]Compound40002200003000

NEEM MURITemperature continues to Riseafter Luminous Front PassesWave speed 800 m/sEnergy being released800m/s x 50μs 40 mm 80 mmT still increasing,const.1.2Al/CuO 14μs 28μs 42μs 0650 700 750 800 850 900Time from Trigger [micro sec]Temmperature [KK]t0Intennsity [arb. unnits]11/lambda1/lambda 2

NEEM MURI Effects of Oxidizer vs Fuel ParticleSizeAluminum: nanoparticles (38nm) from Technanogy, micron-particles (2μm) from ValimetCopper-Oxide: nanoparticles (33nm) and micron particles (3μm) from Sigma AldrichNano Al/ Nano CuOMicron Al/Nano CuONano Al/Micron CuOMicron Al/Micron CuOEnergetic MassLinear Burning Mass Burning Burning Rate Avg. mass perRate [m/s]Rate [kg/s][kg/s]run [g]% mass .080.5317.11822.022.000.891.0micron Al - micron CuOmicron Al / micron CuOLinear propagationrate was moredependant on theCuO particles sizenm Al - micron CuOnm Al / micron CuOmicron Al - nm CuOmicron/ nmnm AlAl-nmAl nmCuOCuO12CuO Cu 2 O O22Evidence that the oxidedecomposition drivesconvective burningnm Al / nm CuO0200400600800LinearBurn rateRate[m/s][m/s]LinearBurning1000

NEEM MURIAl/MoO3 System has Similar TrendEnergetic MassLinear Burning Mass Burning Burning Rate Avg. mass perRate [m/s]Rate [kg/s][kg/s]run [g]% mass Al2O3Oxide ShellThickness(nm)Nano Al/ Nano MoO36781.951.430.2326.46.21Micron Al/Nano MoO33621.541.510.341.722.26Nano Al/Micron MoO3Micron Al/Micron icron Al - micron MoO3micron Al / micron MoO3MoO3 vaporizes atrelatively lowtemperaturestemperatures.Reducing the size ofthese particlespromotes convectiveburningnm Al - micron MoO3nm Al / micron MoO3micron Al - nm MoO3nm Almicron Al / nm MoO3 - nm MoO3nm Al / nm MoO302004006008001000LiLinearBurnBRateRratet [m/s][[m/s]/ ]LinearBurningreducing the oxidizer particle size has greater impact on increasing propagation rate

NEEM MURI Pressure Profiles for Mixtures of Al/CuOand Al/MoO3 with different Powder Sizes30201.82 [[MPa/μs]μ ]Prressure [MMPa]15100.0005Time [[s]]15micro-Al /nano-MoO30.44 [MPa/μs]0.00075Time [s]000.001500200.50 [MPa/μs]101000nano-Al / micro-CuOPrressure [MMPa]micro-Al / nano-CuO0.0015Prressure [MMPa]Prressure [MMPa]300.0005Time [[s]]0.001nano-Al / micro-MoO3100.20 [MPa/μs]5000.00075Time [s]0.0015

NEEM MURI nNi-nAl Burning RatesAl Ni AlNi -1.38 kJ/gTaf 1912 KVertical glass tubes 2”2 in lengthIgnited with Nichrome wireFlame propagation measured withPhantom 7.3StoichiometryCombination123Molar RatioAl : Ni1:11 : 0.561 : 1.38MaterialManufact.SizeAlNovacentrix(nm)80NiAlfa Aesar5-20Mass Percentage (%)Al : Ni29.2 : 90.836 : 6420 : 802Morphology Purity(%)Spherical80Spherical99.9Heat treatment performedon nm Ni powder in ovenat 250 CBurning Rates after HeatTreatment3.5nNi-nAl Burning Rates29% Al1.831.62.51.41.2210.815202530% Al35401.505101520Heat Treatment Duration (min)

NEEM MURIOur work has led to the followingconclusions Further evidence showing that the fast propagationrates in nanothermites are induced by the convectiveburning mechanism Increasing ambient pressure leads to decreased gasgeneration and a changegg in the ppropagationp gmechanism Gas generation is due to decomposition of oxideparticles Temperature rise takes place over a thick region– Reaction relies on pressure, not temperature,gradient to drive propagation– Need only heat mixture to point of gas generation topropagate Reducing the size of oxidizer particles seems toincrease rate of gas generation and promote convectiveburning

NEEM MURISummary - continued Electrostatic self-assembly of nanoscale thermitesinto microspheres show improved mixing oversonication. Nano functionalized colloids of metal oxides andgraphene demonstrated to affect pressureexponentpand burningg rate. Nano aluminum affectsburning rate.