Interfacial stability and contact damage resistance by incorporating buffer layer in thermal barrier coatings

2010 ◽  
Vol 67 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Jae-Young Kwon ◽  
Sung-Il Jung ◽  
Sang-Yeop Lee ◽  
Pyung-Ho Lee ◽  
Je-Hyun Lee ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Interfacial Stability ◽  
Contact Damage ◽  
Damage Resistance ◽  
Barrier Coatings

Interfacial stability and contact damage resistance by incorporating buffer layer in thermal barrier coatings

2010 ◽  
Vol 68 (1-2) ◽  
pp. 135-141 ◽  
Author(s):  
Jae-Young Kwon ◽  
Sung-Il Jung ◽  
Sang-Yeop Lee ◽  
Pyung-Ho Lee ◽  
Je-Hyun Lee ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Interfacial Stability ◽  
Contact Damage ◽  
Damage Resistance ◽  
Barrier Coatings

Improving Contact Damage Resistance of Thermal Barrier Coatings by Incorporating Buffer Layer

2009 ◽  
Vol 620-622 ◽  
pp. 319-322
Author(s):  
Sung Il Jung ◽  
Young Seok Sim ◽  
Jae Hyun Kim ◽  
Je Hyun Lee ◽  
Yeon Gil Jung ◽  
...  
Keyword(s):  
Buffer Layer ◽  
Thermal Barrier Coatings ◽  
Dwell Time ◽  
Thermal Exposure ◽  
Thermal Barrier ◽  
Lower Stress ◽  
Stress Strain ◽  
Barrier Coatings ◽  
Bond Coats ◽  
Tbc Systems

The effects of the introduction of a buffer layer between the bond and top coats on the indentation stress-strain behavior and the contact damage were investigated in air-plasma sprayed (APS) zirconia (ZrO2)–based thermal barrier coatings (TBCs). The microstructure is relatively continuous in the TBC system with the buffer layer, showing Zr, Ni, Cr, and Mg elements between the top and bond coats, whereas the Zr element suddenly disappears by passing the interface between the top and bond coats. The TBC system with the buffer layer shows less strain than that without the buffer layer in the higher stress regions above about 1.3 GPa, while both TBC systems become soft by forming the top coat in the lower stress regions compared with the substrate. The stress–strain curve in both TBC systems is dependent on the dwell time of thermal exposure condition. The TBC system with the buffer layer shows the lower stress-strain curves than that without the buffer layer in thermal cycles with the relatively short dwell time of 1 h, showing the reverse trend with the relatively long dwell time of 10 h. Subsurface damage in substrate is reduced at both indentation loads of P = 500 N and P = 2000 N by introducing the buffer layer, independent of thermal exposure. Therefore, the TBC system with the buffer layer is more efficient in protecting the substrate from contact environments than that without the buffer layer, showing cracking or delamination between the top coat and the buffer layer in the TBC system with the buffer layer.

Mechanical Properties and Damage Durability of Thermal Barrier Coatings with Thermal Fatigue

2006 ◽  
Vol 317-318 ◽  
pp. 525-528
Author(s):  
Hyung Jun Jang ◽  
Dong Beak Kim ◽  
Yeon Gil Jung ◽  
Jung Chel Chang ◽  
Sung Churl Choi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Barrier Coatings ◽  
Thermal Fatigue ◽  
Bond Coat ◽  
Fatigue Behavior ◽  
Cyclic Fatigue ◽  
Thermal Barrier ◽  
Contact Damage ◽  
Barrier Coatings ◽  
Different Thickness

The effects of thermal fatigue conditions on the mechanical and contact damage behavior in thermal barrier coatings (TBCs) are investigated as functions of the bond coat thickness and the preparation method. Three kinds of TBCs with different thickness in the bond coat are prepared by two different methods of APS and HVOF. The static and cyclic thermal fatigues for the TBCs are conducted at temperatures of 950 and 1100 with different dwell times of 10 and 100 hr and 10 cycles at each temperature. Mechanical properties, hardness H and modulus E, in each condition and component are measured by nano-indentation. The contact damage behaviors are investigated by Hertzian indentation, including the cyclic fatigue behavior on the surface of the TBCs. The TGO formation is dependent on both temperature tested and time exposed, showing a similar effect with the cyclic thermal fatigues. The mechanical properties of the TBCs are increased due to the re-sintering of the top coating and the composition change of the bond coat during the thermal fatigues. The contact damage behaviors are affected by the thermal fatigue conditions and the fabrication method, independent of the bond coat thickness.

Thermal cycling behavior and interfacial stability in thick thermal barrier coatings

2010 ◽  
Vol 205 (5) ◽  
pp. 1250-1255 ◽  
Author(s):  
Pyung-Ho Lee ◽  
Sang-Yup Lee ◽  
Jae-Young Kwon ◽  
Sang-Won Myoung ◽  
Je-Hyun Lee ◽  
...  
Keyword(s):  
Thermal Cycling ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Interfacial Stability ◽  
Barrier Coatings ◽  
Thermal Cycling Behavior ◽  
Cycling Behavior

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.

Sign in / Sign up

Export Citation Format

Share Document