Thermal Fracture Resistance of Ceramic Coatings Applied to Metal: I, Elastic Deformation

1959 ◽  
Vol 42 (3) ◽  
pp. 146-150 ◽  
Author(s):  
J. H. LAUCHNER ◽  
D. G. BENNETT
Keyword(s):  
Elastic Deformation ◽  
Fracture Resistance ◽  
Ceramic Coatings ◽  
Thermal Fracture

Finite Element Analysis of Ceramic Coating Systems Under Spherical Indentation With Metallic Interlayer: Part II — Ring Crack Analysis

2005 ◽  
Author(s):  
Minh-Quy Le ◽  
Jin-Woo Yi ◽  
Seock-Sam Kim
Keyword(s):  
Fracture Mechanics ◽  
Fracture Resistance ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Spherical Indentation ◽  
J Integral ◽  
Element Analysis ◽  
Linear Fracture ◽  
Low Elastic Modulus ◽  
Ductile Substrate

Spherical indentation problems of ceramic coatings/metallic inter-layer/ductile substrate were investigated numerically by axisymmetric FEA for two typical ceramic coatings with relatively high and low elastic modulus deposited on aluminum alloy and carbon steel. The fracture mechanics of the ceramic coatings due to occurrence of surface ring cracks extending traverse coating thickness under spherical indenter were considered under the framework of linear fracture mechanics. The J-integral associated to such cracks was computed. The evolution of J-integral versus crack length and indentation depth was studied. The results show that metallic inter-layers can improve the fracture resistance of the ceramic layer under the same indentation conditions.

MULTIPLE SURFACE THERMAL FRACTURE OF GRADED CERAMIC COATINGS

1998 ◽  
Vol 21 (7) ◽  
pp. 715-725 ◽  
Author(s):  
K. Kokini ◽  
Y. R. Takeuchi
Keyword(s):  
Ceramic Coatings ◽  
Thermal Fracture

Electron microscopy studies of plasma-sprayed materials

1983 ◽  
Vol 41 ◽  
pp. 70-71
Author(s):  
K.R. Subramanian ◽  
A.H. King ◽  
H. Herman
Keyword(s):  
Plasma Spraying ◽  
Substrate Surface ◽  
Flame Temperature ◽  
Ceramic Coatings ◽  
Metallic Substrates ◽  
Hot Plasma ◽  
Almost All ◽  
Plasma Sprayed ◽  
Hostile Environments ◽  
Plasma Spraying Process

Plasma spraying is a technique which is used to apply coatings to metallic substrates for a variety of purposes, including hardfacing, corrosion resistance and thermal barrier applications. Almost all of the applications of this somewhat esoteric fabrication technique involve materials in hostile environments and the integrity of the coatings is of paramount importance: the effects of process variables on such properties as adhesive strength, cohesive strength and hardness of the substrate/coating system, however, are poorly understood.Briefly, the plasma spraying process involves forming a hot plasma jet with a maximum flame temperature of approximately 20,000K and a gas velocity of about 40m/s. Into this jet the coating material is injected, in powder form, so it is heated and projected at the substrate surface. Relatively thick metallic or ceramic coatings may be speedily built up using this technique.

Characterization of thermal barrier coatings formed by electon-beam physical vapor deposition (EB-PVD)

1989 ◽  
Vol 47 ◽  
pp. 426-427
Author(s):  
Ozer Unal
Keyword(s):  
Thermal Barrier Coatings ◽  
Physical Vapor Deposition ◽  
Ceramic Coating ◽  
High Vacuum ◽  
Ceramic Coatings ◽  
High Energy ◽  
Thermal Barrier ◽  
Protective Oxide ◽  
Barrier Coatings ◽  
Energy Beam

Interest in ceramics as thermal barrier coatings for hot components of turbine engines has increased rapidly over the last decade. The primary reason for this is the significant reduction in heat load and increased chemical inertness against corrosive species with the ceramic coating materials. Among other candidates, partially-stabilized zirconia is the focus of attention mainly because ot its low thermal conductivity and high thermal expansion coefficient.The coatings were made by Garrett Turbine Engine Company. Ni-base super-alloy was used as the substrate and later a bond-coating with high Al activity was formed over it. The ceramic coatings, with a thickness of about 50 μm, were formed by EB-PVD in a high-vacuum chamber by heating the target material (ZrO2-20 w/0 Y2O3) above its evaporation temperaturef >3500 °C) with a high-energy beam and condensing the resulting vapor onto a rotating heated substrate. A heat treatment in an oxidizing environment was performed later on to form a protective oxide layer to improve the adhesion between the ceramic coating and substrate. Bulk samples were studied by utilizing a Scintag diffractometer and a JEOL JXA-840 SEM; examinations of cross-sectional thin-films of the interface region were performed in a Philips CM 30 TEM operating at 300 kV and for chemical analysis a KEVEX X-ray spectrometer (EDS) was used.

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