PARTICOAT PARTICOAT THEME 4 THEME 4 Nanoscience Nanoscience, - - PDF document

PARTICOAT PARTICOAT

THEME 4 THEME 4 Nanoscience Nanoscience, nanotechnologies, materials new production technologies (NMP) , nanotechnologies, materials new production technologies (NMP) Collaborative Project Collaborative Project Large Large-

• scale integrating project

scale 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 temperatures technology for extreme environments at high temperatures

Grant agreement no.: Grant agreement no.: CP CP-

• I P 211329

I P 211329-

• 2

2

Consortium

GR GR Industry Industry LARCO LARCO 14 14 D D SME SME Steinbeis Steinbeis R R-

• Tech

Tech 13 13 D D Industry Industry Siemens Power Generation Siemens Power Generation 12 12 E E Industry Industry Acciona Acciona Infraestructuras Infraestructuras 11 11 I I SME SME Turbocoating Turbocoating 10 10 F F University University Universit Université é de La Rochelle de La Rochelle 9 9 E E University University Universidad Universidad Carlos III Madrid Carlos III Madrid 8 8 RU RU SME SME Sibthermochim Sibthermochim 7 7 CZ CZ Industry Industry WIP WIP Prague Prague 6 6 GR GR SME SME PyroGenesis PyroGenesis 5 5 E E Industry Industry TECNATOM TECNATOM 4 4 CZ CZ Research Research SV SVÚ ÚM M 3 3 D D Research Research DECHEMA DECHEMA 2 2 D D Research Research Fraunhofer ICT ( Fraunhofer ICT (co co-

• ordinator
• rdinator)

) 1 1 Country Country Business Business Beneficiary Beneficiary name name Beneficiary Beneficiary no. no.

The The Idea Idea

Aluminium: 2-3 μm

Oxidation on heating from room temperature to 1100°C (Microscopy of Oxidation, Birmingham 2005)

Intensität

0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 100 200 300 400 500 600 700 800 900 1000 1100 1200 T [°C] IZ [norm.]

Al 0.3 - 0.7μm Al γ-Al2O3 Θ-Al2O3 α-Al2O3 Intensität

0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1 100 200 300 400 500 600 700 800 900 1000 1100 1200 T [°C] IZ [norm.]

Al 2.0 - 3.0μm Al α-Al2O3

Aluminium: 0,3 – 0,7 μm

The idea: oxidation of The idea: oxidation of nano nano-

• and micro

and micro-

• sized Al

sized Al – – particles particles

x t Parabolic Oxidation

x k dt dx

p

=

x² = 2kp·t

Schematic view of the Transport Processes During Oxide Scale Growth Schematic view of the Transport Processes During Oxide Scale Growth

Oxide Oxygen Containing Environment

Metal Cations Oxygen Anions Electrons Oxide Thickness x

Metal Bulk diffusion coefficients

Conversion Conversion of Metallic

• f Metallic Aluminum

Aluminum Nano Nano/ / Micro Micro Powder Powder Particles Particles Into Into Hollow Hollow Aluminum Aluminum Oxide Oxide Spheres Spheres

Aluminum Aluminum 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-diffusion Al-diffusion

Al Al spherical spherical, 2 , 2-

• 3

3 µ µm m

Scanning 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% 0 Al 31% 0-

• 5

5 µ µm, 69% 5 m, 69% 5-

• 10

10 µ µm m

Potential of Nano- and Micro-Scale Metal Powders

Intensity

0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9 1,0 200 400 600 800 1000 1200 1400 1600 T [°C] IZ [norm.]

α-Al2O3 Al (cubic)

Al and α-Al2O3 portion as a function of temperature

Thermal stability Diffusion 100, 300, 1000 h HT-XRD, metallography CHARACTERIZATION

Suspension Base powder: Al Binder: PVA Al/Binder Dispersant Rheology

“GREEN“ COATING René 80 347H 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

• f 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
• xidation

sintering diffusion

DEPOSITION PROCEDURE THERMAL TREATMENT

Dip-coating

T/°C time

Binder evaporation

Sintering 1 1 10 Assembling

Examples Examples of

• f Coatings

Coatings Produced Produced So Far So Far

Binder # 1 400 Binder # 1 400° °C C

500:1 500:1 5000 5000:1 :1

Vaporization of the organic binder and beginning of Al particle sintering

Binder # 1 650 Binder # 1 650° °C C

500:1 500:1

Densification of the metallic „green“ coating

Binder # 1 650 Binder # 1 650° °C C

3000: 3000:1

Densified aluminum „green“ coating

Binder # 1 900 Binder # 1 900° °C C

500:1 500:1 3000 3000:1 :1

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

Binder # 1 900 Binder # 1 900° °C C

2000: 2000:1 3000 3000:1 :1

Substrate/foam interface

Binder # 2 900 Binder # 2 900° °C C

100:1 100:1

Opened-up surface of the ceramic alumina foam

Binder # 3 650 Binder # 3 650° °C C

1000: 1000:1 5000 5000:1 :1

Hollow ceramic alumina spheres

Binder # 3 900 Binder # 3 900° °C C

1000: 1000:1 5000 5000:1 :1

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

Binder # 3 900 Binder # 3 900° °C C

100 100:1 :1 500 500:1 :1

Possibility to influence the coating/substrate interface (wavy interface = keying effect)

Summary Summary

► ► PARTICOAT

PARTICOAT is is developing developing an innovative an innovative concept concept for for thermal thermal barrier barrier coatings coatings where where in in one

• ne single

single thermal thermal treatment treatment step step a a combined combined bondcoat bondcoat/ / topcoat topcoat system system is is being being formed formed

► ► This

This is is achieved achieved by by the the use use of

• f spherical

spherical nano nano-

• /

/ micro micro-

• scale

scale metal metal particles

• particles. These

. These serve serve as a as a reservoir reservoir for for the the formation formation of

• f the

the Al Al rich rich bond bond coat coat and and are are converted converted into into hollow hollow alumina alumina spheres spheres by by oxidation

• xidation

► ► The

The top top coat coat, in , in the the form of form of the the sintered sintered hollow hollow alumina alumina spheres spheres, , provides provides a thermal a thermal barrier barrier

► ► Initial

Initial results results demonstrate demonstrate the the viability viability of

• f the

the concept concept

Properties Properties

► ►Easy to apply

Easy to apply

► ►Low cost

Low cost

► ►Low application temperatures

Low application temperatures

► ►Possibility to form dense layers with increased

Possibility to form dense layers with increased mechanical compliance mechanical 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 species corrosive species

► ►Significant potential for electrical and thermal

Significant potential for electrical and thermal insulation insulation

► ►Al subsurface reservoir for protective alumina

Al subsurface reservoir for protective alumina scale formation scale formation

Application Application areas areas

► ►Gas turbines in electric power generation and

Gas turbines in electric power generation and aero aero-

• engines

engines

► ►Abradable

Abradable coatings coatings

► ►Steam turbines in electric power generation

Steam turbines in electric power generation

► ►Combustion chambers, boilers

Combustion chambers, boilers

► ►Steam generators,

Steam generators, superheaters superheaters

► ►Waste incineration

Waste incineration

► ►Fire protection of composite materials in

Fire protection of composite materials in construction construction

► ►Reformers and reactors in chemical and

Reformers and reactors in chemical and petrochemical industry petrochemical industry

► ►Electrical insulation in arc melting furnaces

Electrical insulation in arc melting furnaces