PARTICOATPARTICOATTHEME 4THEME 4

NanoscienceNanoscience, nanotechnologies, materials new production technologies (NMP), nanotechnologies, materials new production technologies (NMP)

Collaborative ProjectCollaborative ProjectLargeLarge--scale integrating projectscale integrating project

Proposal full title:Proposal full title:New multipurpose coating systems based on novel particle New multipurpose coating systems based on novel particle technology for extreme environments at high temperaturestechnology for extreme environments at high temperatures

Grant agreement no.: Grant agreement no.: CPCP--IP 211329IP 211329--22

Consortium

GRGRIndustryIndustryLARCOLARCO1414

DDSMESMESteinbeis Steinbeis RR--TechTech1313

DDIndustryIndustrySiemens Power GenerationSiemens Power Generation1212

EEIndustryIndustryAccionaAcciona InfraestructurasInfraestructuras1111

IISMESMETurbocoatingTurbocoating1010

FFUniversityUniversityUniversitUniversitéé de La Rochellede La Rochelle99

EEUniversityUniversityUniversidadUniversidad Carlos III MadridCarlos III Madrid88

RURUSMESMESibthermochimSibthermochim77

CZCZIndustryIndustryWIP WIP PraguePrague66

GRGRSMESMEPyroGenesisPyroGenesis55

EEIndustryIndustryTECNATOMTECNATOM44

CZCZResearchResearchSVSVÚÚMM33

DDResearchResearchDECHEMADECHEMA22

DDResearchResearchFraunhofer ICT (Fraunhofer ICT (coco--ordinatorordinator))11

CountryCountryBusinessBusinessBeneficiaryBeneficiary namenameBeneficiaryBeneficiary no.no.

TheThe

IdeaIdea

Aluminium: 2-3 μm

Oxidation on heating from room temperature to 1100°C

(Microscopy of Oxidation, Birmingham 2005)

Intensität

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

T [°C]

IZ [n

orm

.]

Al 0.3 - 0.7μm

Al

γ-Al2O3

Θ-Al2O3

α -Al2O3

Intensität

0

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9

1

0 100 200 300 400 500 600 700 800 900 1000 1100 1200

T [°C]

IZ [n

orm

.]

Al 2.0 - 3.0μm

Al

α -Al2O3

ab 675°C Schmelze

Aluminium: 0,3 – 0,7 μm

The idea: oxidation of The idea: oxidation of nanonano-- and microand micro--sized Al sized Al –– particlesparticles

x

t

Parabolic Oxidation

xk

dtdx p= x² = 2kp·t

Schematic view of theTransport ProcessesDuring Oxide Scale Growth

Schematic view of theTransport ProcessesDuring Oxide Scale Growth

Oxide OxygenContainingEnvironment

Metal Cations

Oxygen Anions

Electrons

Oxide Thickness x

Metal

Bulk diffusioncoefficients

ConversionConversion of Metallic of Metallic AluminumAluminumNanoNano//MicroMicro PowderPowder ParticlesParticles

IntoInto HollowHollow AluminumAluminum Oxide Oxide SpheresSpheres

AluminumAluminum Aluminum

Aluminum Oxide Aluminum Oxide

Nano/micro size = low amount of grain boundaries

Aluminum = very creep ductile, i. e. adherence to oxide maintained during conversion

Al-diffusionAl-diffusion

Al Al sphericalspherical, 2, 2--3 3 µµmmScanning Electron Microscopy / EDX

- Homogeneous distribution, no agglomerates

- Spherical particles

- Particle size 2-5 μm

10 μm

10 μm

Potential of Nano- and Micro-Scale Metal Powders

Intensity curves iz(T)

Al 31% 0Al 31% 0--5 5 µµm, 69% 5m, 69% 5--10 10 µµmm

Potential of Nano- and Micro-Scale Metal Powders

Intens ity

0,0

0,1

0,2

0,3

0,4

0,5

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0,7

0,8

0,9

1,0

0 200 400 600 800 1000 1200 1400 1600

T [°C]

IZ [

no

rm.]

α-Al2O3 Al (cubic)

Al and α-Al2O3 portion as a function of temperature

Thermal stabilityDiffusion

100, 300, 1000 hHT-XRD, metallography

CHARACTERIZATION

SuspensionBase powder: AlBinder: PVAAl/BinderDispersantRheology

“GREEN“ COATING René 80347H

MCrAlY-2231

THERMAL TREATMENTS

TT1-SINTERING

•Binder evaporation•Al sintering

TT2-ASSEMBLING

•Al2O3 formation• Al diffusion

WORK FLOW CHART

Ni-Base alloys

SS steels

Production of source metal

particles by PSP and EEC

Spherical metal particles with defined size

Deposition by brushing,

spraying, rolling, sol-gel

raw coating

coating with quasi-foam top coat and diffusion layer

Heat treatment ev. pre-treatment

oxidation sintering diffusion

DEPOSITION PROCEDURE

THERMAL TREATMENTDip-coating

T/°C

time

Binder evaporation

Sintering

1 1 10

Assembling

ExamplesExamples of of CoatingsCoatingsProducedProduced So FarSo Far

Binder #1 400Binder #1 400°°CC

500:1 5000:1

Vaporization of the organic binder and beginning of Al particle sintering

Binder #1 650Binder #1 650°°CC

500:1

Densification of the metallic „green“ coating

Binder #1 650Binder #1 650°°CC

3000:1

Densified aluminum „green“ coating

Binder #1 900Binder #1 900°°C C

500:1 3000:1

Broken up „cross-section“ of the ceramic alumina „foam“

Binder #1 900Binder #1 900°°CC

2000:1 3000:1

Substrate/foam interface

Binder #2 900Binder #2 900°°CC

100:1

Opened-up surface of the ceramic alumina foam

Binder #3 650Binder #3 650°°CC

1000:15000:1

Hollow ceramic alumina spheres

Binder #3 900Binder #3 900°°CC

1000:1 5000:1

Influence of binder:

Example of reduced sintering activity and appearance of meta-stable alumina phases

Binder #3 900Binder #3 900°°CC

100:1 500:1

Possibility to influence the coating/substrate interface

(wavy interface = keying effect)

SummarySummary

►► PARTICOAT PARTICOAT isis developingdeveloping an innovative an innovative conceptconcept forforthermal thermal barrierbarrier coatingscoatings wherewhere in in oneone singlesingle thermal thermal treatmenttreatment stepstep a a combinedcombined bondcoatbondcoat//topcoattopcoat systemsystem isisbeingbeing formedformed

►► ThisThis isis achievedachieved byby thethe useuse of of sphericalspherical nanonano--//micromicro--scalescalemetal metal particlesparticles. These . These serveserve as a as a reservoirreservoir forfor thetheformationformation of of thethe Al Al richrich bondbond coatcoat and and areare convertedconverted intointohollowhollow aluminaalumina spheresspheres byby oxidationoxidation

►► TheThe toptop coatcoat, in , in thethe form of form of thethe sinteredsintered hollowhollow aluminaaluminaspheresspheres, , providesprovides a thermal a thermal barrierbarrier

►► Initial Initial resultsresults demonstratedemonstrate thethe viabilityviability of of thethe conceptconcept

PropertiesProperties►►Easy to applyEasy to apply►►Low costLow cost►►Low application temperaturesLow application temperatures►►Possibility to form dense layers with increased Possibility to form dense layers with increased

mechanical compliancemechanical compliance►►Alumina is no oxygen conductor and provides a Alumina is no oxygen conductor and provides a

very good barrier effect against ingress of very good barrier effect against ingress of corrosive speciescorrosive species

►►Significant potential for electrical and thermal Significant potential for electrical and thermal insulationinsulation

►►Al subsurface reservoir for protective alumina Al subsurface reservoir for protective alumina scale formationscale formation

ApplicationApplication areasareas►►Gas turbines in electric power generation and Gas turbines in electric power generation and

aeroaero--engines engines ►►AbradableAbradable coatingscoatings►►Steam turbines in electric power generationSteam turbines in electric power generation►►Combustion chambers, boilersCombustion chambers, boilers►►Steam generators, Steam generators, superheaterssuperheaters►►Waste incinerationWaste incineration►►Fire protection of composite materials in Fire protection of composite materials in

constructionconstruction►►Reformers and reactors in chemical and Reformers and reactors in chemical and

petrochemical industrypetrochemical industry►►Electrical insulation in arc melting furnacesElectrical insulation in arc melting furnaces