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- -scale integrating project scale integrating project Large 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 Beneficiary no. Beneficiary no. Beneficiary name Beneficiary name Business Business Country Country 1 1 Fraunhofer ICT ( Fraunhofer ICT (co co- -ordinator ordinator) ) Research Research D D 2 DECHEMA Research D 2 DECHEMA Research D 3 3 SVÚ SV ÚM M Research Research CZ CZ 4 TECNATOM Industry E 4 TECNATOM Industry E 5 5 PyroGenesis PyroGenesis SME SME GR GR 6 6 WIP WIP Prague Prague Industry Industry CZ CZ 7 Sibthermochim SME RU 7 Sibthermochim SME RU 8 8 Universidad Universidad Carlos III Madrid Carlos III Madrid University University E E 9 9 Université Universit é de La Rochelle de La Rochelle University University F F 10 Turbocoating SME I 10 Turbocoating SME I 11 11 Acciona Acciona Infraestructuras Infraestructuras Industry Industry E E 12 Siemens Power Generation Industry D 12 Siemens Power Generation Industry D 13 13 Steinbeis Steinbeis R R- -Tech Tech SME SME D D 14 14 LARCO LARCO Industry Industry GR GR

The The Idea Idea The idea: oxidation of nano nano- - and micro and micro- -sized Al sized Al – – particles particles The idea: oxidation of Aluminium: 0,3 – 0,7 μ m Aluminium: 2-3 μ m Intensität Intensität 1 1 Al Al 0,9 0,9 α -Al 2 O 3 α -Al 2 O 3 0,8 0,8 0,7 0,7 0,6 0,6 IZ [norm.] IZ [norm.] 0,5 0,5 Θ -Al 2 O 3 0,4 0,4 0,3 0,3 0,2 0,2 γ -Al 2 O 3 0,1 0,1 Al 2.0 - 3.0 μ m ab 675°C Schmelze Al 0.3 - 0.7 μ m 0 0 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 T [°C] T [°C] Oxidation on heating from room temperature to 1100 ° C (Microscopy of Oxidation, Birmingham 2005)

Metal Oxide Oxygen Containing Metal Cations Environment Oxygen Anions Electrons Schematic view of the Schematic view of the Transport Processes Transport Processes Oxide Thickness x During Oxide Scale Growth During Oxide Scale Growth x Parabolic Oxidation k dx = p x² = 2k p ·t dt x t Bulk diffusion coefficients

Conversion of Metallic of Metallic Aluminum Aluminum Conversion Nano Nano/ / Micro Micro Powder Powder Particles Particles Into Into Hollow Hollow Aluminum Aluminum Oxide Oxide Spheres Spheres Aluminum Oxide Aluminum Oxide Al-diffusion Al-diffusion Aluminum Aluminum Aluminum Nano/micro size = low amount of grain boundaries Aluminum = very creep ductile, i. e. adherence to oxide maintained during conversion Potential of Nano- and Micro-Scale Metal Powders Al spherical Al spherical, 2 , 2- -3 3 µ µm m Scanning Electron Microscopy / EDX 10 μ m 10 μ m - Homogeneous distribution, no agglomerates - Spherical particles - Particle size 2-5 μ m

Potential of Nano- and Micro-Scale Metal Powders Al 31% 0- -5 5 µ µm, 69% 5 m, 69% 5- -10 10 µ µm m Al 31% 0 Al and α -Al 2 O 3 portion as a function of temperature Intensity Intensity curves iz(T) 1,0 0,9 α -Al 2 O 3 Al (cubic) 0,8 0,7 0,6 IZ [norm.] 0,5 0,4 0,3 0,2 0,1 0,0 0 200 400 600 800 1000 1200 1400 1600 T [°C] WORK FLOW CHART Binder: PVA Al/Binder Base powder: Al Suspension Dispersant Rheology Ni-Base alloys René 80 “GREEN“ COATING 347H SS steels MCrAlY-2231 TT1- SINTERING •Binder evaporation •Al sintering CHARACTERIZATION Thermal stability THERMAL TT2- ASSEMBLING Diffusion TREATMENTS 100, 300, 1000 h •Al 2 O 3 formation HT-XRD, metallography • Al diffusion

DEPOSITION PROCEDURE Production Deposition of source metal by brushing, particles by spraying, PSP and EEC rolling, sol-gel Spherical metal particles with defined size raw coating Heat treatment ev. pre-treatment oxidation sintering diffusion coating with quasi-foam top coat and diffusion layer THERMAL TREATMENT Dip-coating T/ ° C Assembling Sintering Binder evaporation 1 1 10 time

Examples of of Coatings Coatings Examples Produced So Far So Far Produced Binder # 1 400° °C C Binder # 1 400 500:1 500:1 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° °C C Binder # 1 650 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° °C C Binder # 1 900 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° °C C Binder # 3 650 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° °C C Binder # 3 900 100 100:1 :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 one 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 of 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 of the the Al Al rich rich bond bond coat coat and and are are converted converted into into hollow alumina hollow alumina spheres spheres by by oxidation oxidation ► 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 of 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 areas Application areas Gas turbines in electric power generation and ► Gas turbines in electric power generation and ► aero- -engines engines aero Abradable coatings coatings ► Abradable ► ► 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 ►