NUMERICAL INVESTIGATION ON CERAMIC COATINGS UNDER SPHERICAL INDENTATION WITH METALLIC INTERLAYER- PART I: UNCRACKED COATINGS

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4395-4400
Author(s):  
MINH-QUY LE ◽  
JIN-WO YI ◽  
SEOCK-SAM KIM
Keyword(s):  
Coating Thickness ◽  
Radial Stress ◽  
Ceramic Coating ◽  
Damage Zone ◽  
Ceramic Coatings ◽  
Spherical Indentation ◽  
Element Analysis ◽  
Surface And Interface ◽  
Plastic Damage ◽  
Ductile Substrate

Radial stress distribution and plastic damage zones evolution in ceramic coating/metallic interlayer/ductile substrate systems under spherical indentation were investigated numerically by axisymmetric finite element analysis (FEA) for a typical ceramic coating deposited on carbon steel with various indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios. The results showed that the suitable metallic interlayer could improve resistance of ceramic coating systems through reducing the peak tensile radial stress on the surface and interface of ceramic coatings and plastic damage zone size in the substrate under spherical indentation.

Finite Element Analysis of Ceramic Coating Systems Under Spherical Indentation With Metallic Interlayer: Part I — Uncracked Coatings

2005 ◽  
Author(s):  
Minh-Quy Le ◽  
Jin-Woo Yi ◽  
Seock-Sam Kim
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Coating Thickness ◽  
Radial Stress ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Spherical Indentation ◽  
Model Parameters ◽  
Element Analysis ◽  
Plastic Damage

Spherical indentation problems of ceramic coatings/metallic inter-layer/ductile substrate were investigated numerically by axisymmetric finite element analysis (FEA) for two typical ceramic coatings with relatively high and low elastic modulus deposited on aluminum alloy and carbon steel. Various indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios were used in the modeling. Radial stress distribution and plastic damage zones evolution were discussed in connection with model parameters. The results showed that the suitable metallic interlayer could improve resistance of ceramic coating systems through reducing the peak tensile radial stress on the surface and interface of ceramic coatings and plastic damage zone size in the substrate under spherical indentation.

scholarly journals Stress analysis of ceramic coatings under spherical indentation: Influence of a metallic interlayer

2006 ◽  
Vol 28 (1) ◽  
pp. 21-27
Author(s):  
Le Minh Quy ◽  
Tran Ich Thinh
Keyword(s):  
Coating Thickness ◽  
Radial Stress ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Spherical Indentation ◽  
Model Parameters ◽  
Stress Distributions ◽  
Surface And Interface ◽  
Low Elastic Modulus ◽  
Ductile Substrate

Spherical indentation problems of ceramic coatings/metallic interlayer/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. Various indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios were used in the modeling. Radial stress distributions were discussed in connection with model parameters. The results showed that the suitable metallic interlayer could improve resistance of ceramic coating systems through reducing the peak tensile radial stress on the surface and interface of ceramic coatings.

scholarly journals Plastic damage evolution in multilayer coatings/ductile substrate system under spherical indentation: Influence of a metallic interlayer

2005 ◽  
Vol 27 (2) ◽  
pp. 86-95
Author(s):  
Le Minh Quy ◽  
Tran Ich Thinh
Keyword(s):  
Coating Thickness ◽  
Damage Zone ◽  
Ceramic Coatings ◽  
Spherical Indentation ◽  
Model Parameters ◽  
Multilayer Coatings ◽  
Element Analysis ◽  
Plastic Damage ◽  
Low Elastic Modulus ◽  
Ductile Substrate

Spherical indentation problems of ceramic coatings/metallic inter-layer/ductile substrate were investigated numerically by axisymmetric finite element analysis (FEA) for two typical ceramic coatings with relatively high and low elastic modulus deposited on aluminum alloy and carbon steel. Various indenter radius-coating thickness ratios and interlayer thickness-coating thickness ratios were used in the modeling. Plastic damage zone evolution were discussed in connection with model parameters. The results' showed that the suitable metallic interlayer could improve resistance of ceramic coating systems through reducing the plastic damage zone size in the substrate under spherical indentation.  

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.

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.

Finite Element Modeling of Damage Formation in Rubber-Toughened Polymer

2005 ◽  
Vol 297-300 ◽  
pp. 1019-1024
Author(s):  
Mitsugu Todo ◽  
Yoshihiro Fukuya ◽  
Seiya Hagihara ◽  
Kazuo Arakawa
Keyword(s):  
Finite Element ◽  
Damage Zone ◽  
Damage Model ◽  
Crack Tip ◽  
Optical Microscope ◽  
Toughening Mechanism ◽  
Element Analysis ◽  
Zone Formation ◽  
Macro Scale ◽  
Rubber Toughened

Microscopic studies on the toughening mechanism of rubber-toughened PMMA (RTPMMA) were carried out using a polarizing optical microscope (POM) and a transmission electron microscope (TEM). POM result showed that in a typical RT-PMMA, a damage zone was developed in the vicinity of crack-tip, and therefore, it was considered that energy dissipation due to the damage zone development was the primary toughening mechanism. TEM result exhibited that the damage zone was a crowd of micro-crazes generated around rubber particles in the vicinity of notch-tip. Finite element analysis was then performed to simulate such damage formations in crack-tip region. Macro-scale and micro-scale models were developed to simulate damage zone formation and micro-crazing, respectively, with use of a damage model. It was shown that the damage model introduced was successfully applied to predict such kind of macro-damage and micro-craze formations.

Variable Parameter Processes of Micro-Arc Oxidation for Aluminium Alloy

2011 ◽  
Vol 704-705 ◽  
pp. 1273-1278
Author(s):  
Cheng Gao ◽  
Jin Yong Xu ◽  
Xuan Yi Shi ◽  
Ya Juan Liu ◽  
Jing Chun Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Wear Rate ◽  
Ceramic Coating ◽  
Early Stage ◽  
Variable Parameter ◽  
Ceramic Coatings ◽  
Constant Current ◽  
Constant Voltage ◽  
Micro Arc Oxidation ◽  
The Way

In micro-arc oxidation process, ceramic coating had a rapid growth all along by the way of constant current oxidation, and ceramic coating had a low roughness by the way of constant voltage oxidation. But few research focus on the mixed control process of constant current oxidation and constant voltage oxidation. In this paper we propose a variable parameter process that can combine the advantages of constant current and constant voltage oxidation for the first time. The growth kinetics of different technics was analyzed according to the change law of current and voltage. Surface topographs of ceramic coating were observed using scanning electron microscopy (SEM). The friction tests were carried out using a self-made friction tester. The results show that ceramic coating has an upper growth rate and a low roughness by the process of constant current+constant voltage oxidation. The ceramic coating has a high growth rate by process of constant voltage+constant current oxidation. The results of friction test indicate that the wear rate and roughness of ceramic coating are positive correlation at early stage of friction. While the ceramic coatings treated by different technics have the close wear rate at stable friction stage, which embodies the inner layer of ceramic coating has a well antiwear behavior.

Interaction of a Crack in the Plasma-Sprayed Ceramic Coating with the Metal Substrate

2005 ◽  
Vol 482 ◽  
pp. 223-226
Author(s):  
Luboš Náhlík ◽  
Zdeněk Knésl ◽  
F. Kroupa
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Surface Crack ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Metal Substrate ◽  
High Density ◽  
Initial Surface ◽  
Young’S Moduli ◽  
Plasma Sprayed

Plasma-sprayed ceramic coatings contain a high density of intrasplat microcracks which are responsible for small Young’s moduli and low fracture toughness. The extension of an initial surface crack in the direction to the interface, where the crack is repelled by the metal substrate with higher Young’s modulus, is studied using the methods of fracture mechanics. It is shown that high tensile stresses induced by the crack in the interface can lead to a local decohesion along the interface so that the crack can deviate into the interface.

scholarly journals Effect of Anodic Current Density on Characteristics and Low Temperature IR Emissivity of Ceramic Coating on Aluminium 6061 Alloy Prepared by Microarc Oxidation

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Mohannad M. S. Al Bosta ◽  
Keng-Jeng Ma ◽  
Hsi-Hsin Chien
Keyword(s):  
Surface Roughness ◽  
Current Density ◽  
Ceramic Coating ◽  
Microarc Oxidation ◽  
Ceramic Coatings ◽  
Anodic Current Density ◽  
Ceramic Surface ◽  
Anodic Current ◽  
Alumina Phase ◽  
Current Densities

High emitter MAO ceramic coatings were fabricated on the Al 6061 alloy, using different bipolar anodic current densities, in an alkali silicate electrolyte. We found that, as the current density increased from 10.94 A/dm2 to 43.75 A/dm2, the layer thickness was increased from 10.9 μm to 18.5 μm, the surface roughness was increased from 0.79 μm to 1.27 μm, the area ratio of volcano-like microstructure was increased from 55.6% to 59.6%, the volcano-like density was decreased from 2620 mm−2 to 1420 mm−2, and the γ-alumina phase was decreased from 66.6 wt.% to 26.2 wt.%, while the α-alumina phase was increased from 3.9 wt.% to 27.6 wt.%. The sillimanite and cristobalite phases were around 20 wt.% and 9 wt.%, respectively, for 10.94 A/dm2 and approximately constant around 40 wt.% and less than 5 wt.%, respectively, for the anodic current densities 14.58, 21.88, and 43.75 A/dm2. The ceramic surface roughness and thickness slightly enhanced the IR emissivity in the semitransparent region (4.0–7.8 μm), while the existing phases contributed together to raise the emissivity in the opaque region (8.6–16.0 μm) to higher but approximately the same emissivities.

Finite element analysis of spherical indentation to study pile-up/sink-in phenomena in steels and experimental validation

2012 ◽  
Vol 54 (1) ◽  
pp. 74-83 ◽  
Author(s):  
V. Karthik ◽  
P. Visweswaran ◽  
Anand Bhushan ◽  
D.N. Pawaskar ◽  
K.V. Kasiviswanathan ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Validation ◽  
Spherical Indentation ◽  
Element Analysis ◽  
Pile Up
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