Sol-gel preparation and characterization of corundum based ceramic oxidation protection coatings [Elektronische Ressource] / Martin Dressler

Mdressle

Informations

• Publié par: technische_universitat_bergakademie_freiberg
• Publié le: 01 janvier 2006
• Nombre de lectures: 15
• Langue: English
• Poids de l'ouvrage: 4 Mo

Extrait

“Sol-Gel Preparation and Characterization of
Corundum Based Ceramic Oxidation
Protection Coatings”


Von der Fakultät für Maschinenbau, Verfahrens- und Energietechnik
der Technischen Universität Bergakademie Freiberg
genehmigte



DISSERTATION



zur Erlangung des akademischen Grades
Doktor der Ingenieurwissenschaften
Dr.-Ing.



vorgelegt



1von: Dipl.-Ing. Martin Dressler



geboren am: 30. August 1977 in: Freiberg



Gutachter:
Prof. Dr.-Ing. habil. Christos G. Aneziris, TU-Bergakademie Freiberg
Prof. Dr.-Ing. habil. Horst Biermann, TU-Bergakademie Freiberg
Dr. sc. nat. Marianne Nofz, Bundesanstalt für Materialforschung und -prüfung




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ii






dedicated to

M. Nofz












I believe what true scientific
work constitutes is the
unselfish thirst for
knowledge; which is paradox
because eventually it is this
approach which brings about
the most sensational
practical consequences.

Irène Joliot-Curie, winner of the Nobel prize
for chemistry 1938

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iv ABSTRACT

he Ni-base superalloy, IN-718, has been coated with alumina sols. Coated surfaces, carrying T alumina layers having thicknesses between 0.6 µm and 3.6 µm show a significantly reduced
oxidation rate when compared with uncoated reference surfaces, even if heating temperature is
increased up to 900 °C and heating time is extended to 800 h.
Alumina layers were prepared via sol-gel processing using a modified Yoldas procedure to obtain
alumina sols. No change in rheological sol behavior was observed for more than 1 year of aging
under static conditions at room temperature. Depending on pH value, modified Yoldas sols
contain a manifold of Al species, among them Al polycations. Thermal evolution of sol derived 13
alumina powders depends on Al speciation of parent sols. Depending on sol composition, both
gamma-Al O and eta-Al O occur as intermediate transition aluminas. 2 3 2 3
Phase composition and gas phase velocity influence oxygen permeability of thin layers prepared
with modified Yoldas sols.





























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vi LIST OF ABBREVIATIONS


AC .....................................................................acrylate
AS......................................................................acoustic spectrometer (spectrometry)
ASB ...................................................................aluminum tri-sec-butoxide
BCbond coat
CTEcoefficient of thermal expansion
DTAdifferential thermal analysis
DTGal gravimetry
EDXenergy dispersive X-ray
FIB.....................................................................focused ion beam
MAS ..................................................................magic angle sample spinning
MSmass spectrometry
NMRnuclear magnetic resonance
POE ...................................................................polyethyleneoxide
PVP....................................................................polyvinylpyrrolidon
SEMscanning electroni microscope (microscopy)
SSAsingle scattering approximation
SSPsol-suspension
TBCthermal barrier coating
TEM ..................................................................transmission electron microscope (microscopy)
TGOthermally grown oxide



























viiLIST OF FIGURES


Figure 2.1 ................................................................................................4
Figure 2.26
Figure 2.37
Figure 2.410
Figure 2.510
Figure 3.118
Figure 3.218
Figure 3.319
Figure 3.422
Figure 3.5 ................................................................................................23
Figure 3.627
Figure 3.727
Figure 3.828
Figure 3.928
Figure 4.129
Figure 4.2 ................................................................................................31
Figure 4.331
Figure 4.432
Figure 4.532
Figure 4.633
Figure 4.733
Figure 4.834
Figure 4.9 ................................................................................................34
Figure 4.10 ..............................................................................................35
Figure 4.1136
Figure 4.1236
Figure 4.1337
Figure 4.1437
Figure 4.1538
Figure 4.1638
Figure 4.1739
Figure 4.1839
Figure 4.1940
Figure 4.2040
Figure 4.21 ..............................................................................................41
Figure 4.2242
Figure 4.2342
Figure 4.2443
Figure 4.2543
Figure 4.2644
Figure 4.2744
Figure 4.2844
Figure 4.2947
Figure 4.3048
Figure 4.3148
Figure 4.32 ..............................................................................................49
Figure 4.3350

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Figure 4.34 ..............................................................................................53
Figure 4.3554
Figure 4.3656
Figure 4.3757
Figure 4.3857
Figure 4.3958
Figure 4.4058
Figure 4.4159
Figure 4.4259
Figure 4.43 ..............................................................................................61
Figure 4.4462
Figure 4.4564
Figure 4.4664
Figure 4.4765
Figure 4.4865
Figure 4.4965
Figure 4.50 ..............................................................................................66
Figure 4.5167
Figure 4.5267
Figure 4.5368
Figure 4.5469
Figure 4.5569
Figure 4.5670
Figure 4.5771
Figure 4.5872
Figure 4.5972
Figure 4.6073
Figure 4.61 ..............................................................................................73
Figure 5.1 ................................................................................................76
Figure 5.280
Figure 5.384
Figure 5.488
Figure 5.594
Figure 5.6107
Figure 5.7118
Figure 9.1138
Figure 9.2138
Figure 9.3138
Figure 9.4139
Figure 9.5 ................................................................................................140






ixLIST OF TABLES


Table 2.1 .................................................................................................11
Table 3.123
Table 4.130
Table 4.232
Table 4.345
Table 4.454
Table 4.555
Table 4.660
Table 4.760
Table 4.8 .................................................................................................63
Table 4.966
Table 4.10 ...............................................................................................67
Table 4.1169
Table 4.1270
Table 5.189
Table 5.2 .................................................................................................93
Table 9.1143































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