page 1 — le-tex 1 Abel Test This test on chemical stability was propos

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1
AbelTest
ThistestonchemicalstabilitywasproposedbyAbelin1875.Thetest
parameterdeterminedisthetimeafterwhichamoistpotassiumiodide
starchpaperturnsvioletorbluewhenexposedtogasesevolvedbyone
gramoftheexplosiveat82.2°C(180°F).
In commercial nitroglycerine explosives, for example, this coloration
onlydevelopsafter10minor more.Inamore sensitivevariantofthe
method,Zinciodide–starchpaperisemployed.
TheAbeltestisstillusedinqualitycontrolofcommercialnitrocellulose,
butiscurrentlynolongeremployedinstabilitytestingofpropellants.
Acceptor1)
Empfängerladung;chargeréceptrice
Achargeofexplosivesorblastingagentreceivinganimpulsefroman
exploding→Donorcharge.
Acremite
ThisisthenamegivenbytheUSinventorAcretohismixtureofabout
94%ammoniumnitratewith6%fueloil.Thismixturewasatfirstpre-
paredinaprimitivemannerbytheusersthemselvestoobtainavery
cheapexplosiveforopenpitminingunderdryconditions.Like→ANFO,
thematerialhaswidelydisplacedconventionalcartridgedexplosives.
Actuator
Mechanicaldeviceoperatedbyasolidpropellant.
Adiabatic
Processesorphenomenaassumedtooccurinaclosedsystemwithout
energyexchangewiththesurroundings.
adiabaticflametemperature
The temperature obtained by thermodynamics calculations for the
productsofcombustionofenergeticmaterialsneglectingenergyloss
tothesurroundings.
1) Textquotedfromglossary.
Explosives,7.Edition,RudolfMeyer,JosefKöhler,andAxelHomburg.
©2015WILEY-VCHVerlagGmbH&Co.KGaA.Published2015byWILEY-VCHVerlagGmbH&Co.KGaA.
AdobeCharge 2
isobaricadiabaticflametemperature
Adiabaticflame temperatureattained underconstant pressure condi-
tions.
isochoricadiabaticflametemperature
Adiabatic flame temperature attained under constant volume condi-
tions.
adiabatictemperature
Thetemperatureattainedbyasystemundergoingavolumeorpressure
changeinwhichnoheatentersorleavesthesystem.
AdobeCharge
Auflegerladung;pétardage
Synonymouswith→MudCap
ADR
Abbreviation for “Accord Européen Relatif au Transport des March-
andisesDangereusesparRoute”(EuropeanAgreementConcerningthe
internationalCarriageofDangerousGoodsbyRoad).Itisbasedonthe
RecommendationsontheTransportofDangerousGoodsModelRegu-
lations(UnitedNations).
Aerozin
Aliquidfuelforrocketenginesthatiscomposedof50%anhydroushy-
drazineand50%asym-dimethylhydrazine.
AGARD
Abbreviation for the NATO Advisory Group for Aeronautical Research
andDevelopment.
Airbag
Gasgenerator
Thebasicideaoftheairbagasapassiverestraintsysteminamotorve-
hiclewasalreadypatentedforthefirsttimein1951inGermany.How-
ever,ittook nearly20 years before developmentbegan on two basic
types–pyrotechnicandhybridgasgenerators.Bothtypesaremanufac-
turednearlyexclusivelyinseriesproductionandwereincludedincars
3 Airbag
Figure1 Sectionaldiagramofapyrotechnicalgasgeneratorforairbags.
startingin1975.Mainstreamapplicationsofairbagrestraintsystemsin
almosteverycarstartedin1990.
Nowadays four main types of gas generating principles are used for
airbag inflators in cars. Pyrotechnic gas generators inflate the bag by
gaseouscombustionproductsofpyrotechniccompositions.Hybridgas
generatorsarebasedonacombinationofpressurizedgasandpyrotech-
nic(heating) charge todeliverthe gas. Both typesare widelyusedin
driver, passenger, side and curtain airbag applications. So-called cold
gasgeneratorsutilizepressurizedheliumforbaginflationandareusu-
allyusedforkneeandsideairbagsystems.Thelatestdevelopmentin
gas generating principles uses a combustible mixture of pressurized
hydrogen,oxygenandinertgasbeingappliedfordriverandpassenger
applications.Hybridandpyrotechnicgasgeneratorsarethemostcom-
montypesusedandaredescribedindetailbelow.Theirconstructionis
shownschematicallyinFigures1and2.
Inthehybridsystemthepre-pressurizedgas(nitrogen,argon/helium)
is stored in pressure containers fitted with a burst disc. Opening this
membrane by pyrotechnic means allows the gas to flow out intothe
airbag.Thecoolingoftheexpandinggasiscompensatedorevenover-
compensatedbythepyrotechniccharge.Sincethetotalamountofpy-
rotechnicmixtureissmallinquantitativeterms,thecompulsorythresh-
oldvaluesofthetoxicimpuritiescontainedintheworkinggascanbe
adheredtorelativelyeasily.Thisfact,inadditiontotheidealtempera-
tureoftheworkinggas,isthemainadvantageofhybridgasgenerators.
Airbag 4
Figure2 Sectionaldiagramofahybridgasgeneratorforairbags.
Thedisadvantagesarethelargerweightcomparedtopyrotechnicgas
generators,themorecomplexproductiontechnologyneededandthe
subjectiontopressurevesselregulation.
Theuniquefeatureofalmostallpyrotechnicalgasgeneratorsisthecon-
centricassemblyofthreedifferentchamberswithdesignscorrespond-
ing to their pressure conditions and functions. The innermost cham-
ber containsthe booster unitconsisting of aplug,squiband booster
charge. An auto ignition charge is usually integrated in the booster
setup,whosetaskistoignitethepyrotechnicmixturewithoutelectric
current in case of high temperatures,e.g. in case of fire. Duringstan-
dardelectricalignitionthethinresistancewireoftheigniterisheated
andtheignitiontrainstarted.Theboosterchargeusuallyusedinearlier
times was boron/potassium nitrate. Nowadays pyrotechnic formula-
tionswithgoodignitionpropertiesareusedinpelletizedgraindesign
contributingnoticeablytotheoverallgasyieldofthegenerator.Thehot
gases and particles generatedby this charge enterthe concentrically
arrangedcombustionchamberandignitethepyrotechnicmaincharge.
Bothchambersaredesignedforhighpressuresupto60MPa.Thepy-
rotechnicmainchargeconsistsgenerallyofcompressedpelletswhich
5 Airbag
Table1 EffluentgaslimitsaccordingUSCAR-24regulation.
EffluentGas VehicleLevelLimit Driver-SideLimit
(ppm) (ppm)
Chlorine(Cl ) 1 0.25
2
Carbonmonoxide(CO) 461 115
Carbondioxide(CO ) 30000 7500
2
Phosgene(COCl ) 0.33 0.08
2
Nitricoxide(NO) 75 18.75
Nitrogendioxide(NO ) 5 1.25
2
Ammonia(NH ) 35 9
3
Hydrogenchloride(HCl) 5 1.25
Sulphurdioxide(SO ) 5 1.25
2
Hydrogensulfide(H S) 15 3.75
2
Benzene(C H ) 22.5 5.63
6 6
Hydrogencyanide(HCN) 4.7 1.18
Formaldehyde(HCHO) 1 0.25
generatetheworkinggasandslagresiduesbyacombustionprocess.
Theproductsleavethecombustionchamberthroughnozzlesanden-
terthe lowpressure regionofthe filtercompartment,where theslag
isremovedfromthegasflow.Thefiltercompartmentisequippedwith
varioussteelfiltersanddeflectorplates.Thegasthenflowsthroughthe
filtercompartmentnozzlesintothebag.
Thebasictaskofeachgasgeneratoristoprovidesufficientnontoxicgas
(seeTable1)withintherequiredtimeframeof11–30mstoinflatethe
airbagtothespecifiedpressure.Thefirstpyrotechnicmixtureusedin
airbaggasgeneratorswasbasedonsodiumazide.Duringcombustion,
sodiumazidereactswithoxidizingagents,whichbondchemicallythe
elementalsodiumasthenitrogenisreleased.Establishedoxidizerswere
alkaliandalkalineearthnitrates,metaloxides(e.g.CuO,Fe O ),metal
2 3
sulfides(MoS ) and sulfur.If necessaryslag forming agents(e.g. SiO ,
2 2
aluminosilicates)were also added.Advancesinenvironmental aware-
nessledconsequentlytothereplacementofsodiumazide,thoughpure
nitrogenasaworkinggaswasgeneratedbythiscomposition.Another
factortothedetrimentofsodiumazidewastherelativelowspecificgas
yieldandtheunsolveddisposalprocedureforthistypeofpyrotechnic
mixture.
With regard to azide-free gas mixtures, there have been numerous
patents and initial applications since the early 1990s. These new gas
mixtures generate more gas per gram (gas yields from gas mixtures
AirBlast 6
containing NaN : 0.30–0.35l/g) and thus enable smaller and to some
3
extentamorelightweightconstructionofthegasgenerators.
Theycanbeclassifiedintotwocategories:
1. High-nitrogen organic compounds(C, H,O, N)are combined with
inorganicoxidizers:
The fuels are, for example, 5-aminotetrazole, azodicarbonamide,
→Guanidinenitrate,→Nitroguanidine,dicyandiamide,→Triamino-
guanidinenitrateandsimilarcompounds,aswellassaltsof,forex-
ample, 5-nitrobarbituric acid, urea derivativesand also nitramines
andsimilarcompounds.Theoxidizersare,forexample,alkalioral-
kaline earth nitrates, →Ammoniumnitrate, alkali or alkaline earth
perchloratesandmetaloxides.
Gasyieldofthesemixtures:0.50–0.65l/g.
2. High-oxygen,nitrogen-freeorganiccompounds(C,H,O)areblended
with inorganic oxidizers.The fuelsused are, for example,tri or di-
carboxylicacids(e.g.citricacid,tartaricacid,fumaricacid)orsimilar
compounds.Theoxidizersusedareespeciallyperchloratesandchlo-
rateswithadditionalassistancefrommetaloxides.Thisenablesany
formationofNOxtobeexcluded.Gasyieldofthemixture:0.5–0.6l/g.
Thegasgeneratorformulationsareusuallymanufacturedbygrinding
andblendingtherawmaterials,whichafterapre-compactingstepare
pressedintopelletsordisksonrotarytablepresses.Somegasgenera-
torformulationsusingplastic(reactive)bindersaremanufacturedbyan
extrusionprocess.
AirBlast
Druckwelle;ondedechoc
Theairborneacousticorshockwavegeneratedbyanexplosion→De-
tonation,→FuelAirExplosives,→ThermobaricExplosives.
AirLoaders
Blasgeräte;chargeurspneumatiques
Airloadersserve tocharge prilled→ANFOblastingagentsintobore-
holes.Ifthefree-runningprillscannotbechargedbypouring,e.g.hor-
izontalboreholes,boreholeswithneglectableslopeorboreholeswith
smalldiameters,theycanbeintroducedbyairloaders.Thisisdoneby
loadingthechargeintoapressurizedvesselandapplyinganairpressure
ofabout0.4MPa;avalveatthelowestpointofthemachine,whichcan
becontrolledfromtheboreholetobefilled,leadstoalonghose;when
thevalveisopened,astreamofaircontainingtheexplosivechargein
suspensionissentthroughitintotheborehole.Otherportablemachines
workontheinjectorprinciple.
7 AkarditeII
AkarditeI
diphenylurea;Diphenylharnstoff;diphénylurée
colorlesscrystals(molecularweight:212.25g/mol)
empiricalformula:C H N O
energyofformation:13−11127.23kcal∕kg=−490.6kJ∕kg
enthalpyofformation:−138.2kcal∕kg=−578.2kJ∕kg
oxygenbalance:−233.7%
nitrogencontent:13.21%
density:1.276g∕cm3
Akardite I serves as a →Stabilizer for gunpowders, in particular for
→Double-BasePropellants.
Specifications
meltingpoint: atleast183°C=361°F
moisture: notmorethan0.2%
ashes: notmorethan0.1%
chlorides: notmorethan0.02%
pHvalue: atleast5.0
acid,0.1NNaOH∕100g: notmorethan2.0cm3
AkarditeII
methyldiphenylurea; Methyldiphenylharnstoff; N-méthyl-N′,N′-diphényl-
urée
colorlesscrystals
empiricalformula:C H N O
14 14 2
molecularweight:226.3g/mol
energyofformation:−90.5kcal∕kg=−378.5kJ∕kg
enthalpyofformation:−112.7kcal∕kg=−471.5kJ∕kg
oxygenbalance:−240.4%
nitrogencontent:12.38%
density:1.236g∕cm3
AkarditeIIisaneffective→Stabilizerfordouble-basegunpowders
AkarditeIII 8
Specifications
sameasforAkarditeI,
exceptmeltingpoint atleast170−172°C=338−342°F
AkarditeIII
ethyldiphenylurea;Ethyldiphenylharnstoff;N-éthyl-N′,N′-diphénylurée
colorlesscrystals
empiricalformula:C H N O
15 16 2
molecularweight:240.3g/mol
energyofformation:−128.5kcal∕kg=−537.7kJ∕kg
enthalpyofformation:−151.9kcal∕kg=−635.5kJ∕kg
oxygenbalance:−246.3%
nitrogencontent:11.65%
density:1.128g∕cm3
AkarditeIIIisaneffective→Stabilizerfordouble-basepropellants.Both
AkarditeIIandIIIaregelatinizersaswellas→Stabilizers.
Specifications
sameasforAkarditeI,
exceptmeltingpoint atleast89°C=192°F
Alex
Alexisan→aluminumpowderformedbyexplosionofelectricallyheated
aluminumwiresininertatmosphereswithparticlesizesbetween50and
200nm.Duetoapassivationlayerofthicknessbetween2and4nm,a
substantial numberof theparticlesare alreadyconvertedtoalumina,
theformationofwhichshouldbeavoidedbyinsitucoating.Inaddition
tothediffusioncontrolledoxidationatlowertemperatures,apartialoxi-
dationoftheparticlescanoccurbyafastchemicallycontrolledreaction.
Alexcanincreasetheburningrateofsolidcompositerocketpropellants
uptoafactoroftwo.Anincreaseofdetonationvelocityisnotconfirmed
butAlexmightimprove→airblastorfragmentvelocitiesofsomehigh
explosives,andviscosityincreasesinformulationswithliquidbinders.
Alginates
Saltsofalginicacidwhicharecapableofbinding200–300timestheir
ownvolumeofwater.Theyareaddedasswellingorgellingagentsto
9 Amatols
explosivemixturesinordertoimprovetheirresistancetomoistureand
to→Slurriestoincreaseviscosity.
AllFire
Mindestzündstrom;ampèrageminimed’amorcage
Minimumcurrentthatmustbeappliedtoanignitercircuitforreliable
ignitionoftheprimerchargewithoutregardtotimeofoperation.
AluminumPowder
Aluminiumpulver;poudred’aluminum
Aluminumpowderisfrequentlyaddedtoexplosivesandpropellantsto
improvetheirperformance.Theadditionofaluminumresultsinconsid-
erablegaininheatofexplosionbecauseofthehighheatofformationof
aluminia(1658kJ/mol,16260kJ/kg)leadingtohighertemperaturesof
thefumes.Aluminumnotreactedinthedetonationfrontmightbeox-
idizedbyatmosphericoxygentoinducepost-heatinginthefumezone
andtoincreasethe→airblastoreventoinitiateadelayedsecondary
explosion.
Widely used mixtures of explosives with aluminum powder include
→Ammonals,→DBX,→HBX-1,→Hexal,→Minex,→Minol,→Torpex,
→Trialenes,→Tritonal andHexotonal. Inaddition,underwaterexplo-
sivesoftencontainaluminumpowders.
The performance effect produced by aluminumpowder is frequently
utilizedin→Slurries,alsoin→CompositePropellants.
Importantcharacteristicsofaluminumpowdersareshapeandgrainsize
of the powder granules. Waxed and unwaxed qualitiesare marketed.
Propellantformulationsoftenprescribesystematicallyvariedgrainsizes
forobtainingoptimaldensities.
Amatex
Apourablemixtureoftrinitrotoluene,ammoniumnitrateandRDX.
Amatols
Pourablemixturesofammoniumnitrateandtrinitrotolueneofwidely
varying compositions (40 : 60,50 : 50, 80 : 20). The composition 80 :
20maybeloadedintogrenades,forexample,usingascrewpress(ex-
truder).
Ammonals 10
Ammonals
Compressibleorpourablemixturescontainingammoniumnitrateand
aluminumpowder;thepourablemixturescontain→TNT
AmmoniumAzide
Ammoniumazid;azotured’ammonium
NH N
4 3
colorlesscrystals
molecularweight:60.1g/mol
energyofformation:+499.0kcal∕kg=+2087.9kJ∕kg
enthalpyofformation:+459.6kcal∕kg=+1922.8kJ∕kg
oxygenbalance:−53.28%
nitrogencontent:93.23%
density:1.346g∕cm3
Ammoniumazideispreparedbyintroducingasolutionofammonium
chlorideandsodiumazideintodimethylformamideat100°C.Thesol-
ventisthendrawnoffinvacuum.Owingtoitshighvaporpressure,this
compoundhasnotyetfoundanypracticalapplication.
Vaporpressure:
Pressure Temperature
(mbar) (°C) (°F)
1.3 29.2 84.6
7 49.4 121.0
13 59.2 138.6
27 69.4 157.0
54 80.1 176.2
80 86.7 188.1
135 95.2 203.4
260 107.7 225.9
530 120.4 248.7
1010 133.8 272.8
AmmoniumChloride
Ammoniumchlorid;chlorured’ammonium
NH Cl
4
colorlesscrystals
molecularweight:53.49g/mol