Microstructural Features of EB-PVD Thermal Barrier Coatings Irradiated by High-Intensity Pulsed Ion Beam

2008 ◽  
Vol 373-374 ◽  
pp. 300-303 ◽  
Author(s):  
C. Liu ◽  
X.G. Han ◽  
X.P. Zhu ◽  
M.K. Lei
Keyword(s):  
Electron Microscope ◽  
Thermal Barrier Coatings ◽  
High Intensity ◽  
Physical Vapor Deposition ◽  
Ion Beam ◽  
Thermal Barrier ◽  
X Ray Diffraction ◽  
Barrier Coatings ◽  
Transmission Electron ◽  
Single Column

Thermal barrier coatings (TBCs) fabricated by electron-beam physical-vapor deposition (EB-PVD) were irradiated by high-intensity pulsed ion beam (HIPIB) at an ion current density of 100 A/cm2 with a shot number of 1-10. Microstructural features of the irradiated EB-PVD TBCs were characterized by using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM), respectively. All the HIPIB-irradiated EB-PVD TBC surfaces present smooth and densified features. The originated intercolumnar channels growing out to the top-coat surface and nanometer-scale gaps inside each single column were sealed after the remelting of TBC surface induced by HIPIB, resulting in formation of a continuous remelted layer about 1-2 μm in thickness. The dense remelted layer can work as a barrier against the heat-flow and corrosive gases, and gives the possibility of improving thermal conductivity and oxidation resistance of the HIPIB irradiated EB-PVD TBC.

Structure and Performance of YSZ Thermal Barrier Coatings Irradiated by High Intensity Pulsed Ion Beam

2012 ◽  
Vol 538-541 ◽  
pp. 2377-2381 ◽  
Author(s):  
Xian Xiu Mei ◽  
Yue Liu ◽  
Xue Ma ◽  
You Nian Wang
Keyword(s):  
Thermal Barrier Coatings ◽  
High Intensity ◽  
Ion Beam ◽  
Xrd Analysis ◽  
Isothermal Oxidation ◽  
Atmospheric Plasma ◽  
Cubic Phase ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Micro Cracks

The thermal barrier coatings (TBC) of the yttria-stabilized zirconia (YSZ) has been deposited by the atmospheric plasma spraying (APS),followed by the irradiation of high intensity pulsed ion beam (HIPIB) with the voltage of 250 KV and the ion current density of 300 A/cm2 and pulsed times of 2, 5, 10 and 20, respectively. The X-ray diffraction (XRD) analysis reveals that the coating is characterized by the tetragonal ZrO2 phase instead of the cubic phase and the original monoclinic phase after the irradiation. The scanning electron micros cope analysis demonstrates that the HIPIB treatment leads to a smooth TBC surface, but produces micro-cracks and round grain at the surface. This implies that the plasma erupts during the ion beam interaction with the coatings with poor thermal conductivity, and the micro-cracks were produced in the cooling process. The isothermal oxidation experiment performed at 1050°C in air and suggests that the oxidation resistance of the coating can be largely enhanced after HIPIB treatment.

Research on ZrO 2 Thermal Barrier Coatings Modified by High-Intensity Pulsed Ion Beam

2008 ◽  
Vol 25 (4) ◽  
pp. 1266-1269 ◽  
Author(s):  
Wu Di ◽  
Liu Chen ◽  
Zhu Xiao-Peng ◽  
Lei Ming-Kai
Keyword(s):  
Thermal Barrier Coatings ◽  
High Intensity ◽  
Ion Beam ◽  
Thermal Barrier ◽  
Barrier Coatings

Cyclic Oxidation Behavior of Thermal Barrier Coatings Irradiated by High-Intensity Pulsed Ion Beam

2008 ◽  
Vol 33-37 ◽  
pp. 1337-1344
Author(s):  
Yi Qi Wang ◽  
W.K. Joo ◽  
Chae Sil Kim ◽  
Jung I. Song
Keyword(s):  
Weight Gain ◽  
Thermal Barrier Coatings ◽  
High Intensity ◽  
Cyclic Oxidation ◽  
Ceramic Coating ◽  
Ion Beam ◽  
Thermal Barrier ◽  
Bonding Layer ◽  
Barrier Coatings ◽  
Columnar Grains

High-temperature oxidation resistance of 7 wt.％Y2O3-ZrO2 thermal barrier coatings (TBCs) irradiated by high-intensity pulsed ion beam (HIPIB) has been investigated in a cyclic oxidation condition at 1050 °C ×1 h. The ceramic coating of a tetragonal ZrO2 phase structure was prepared on GH33 superalloy substrates with a NiCoCrAlY bond coat by using electron-beam physical-vapor deposition (EB-PVD). The ceramic coating is composed of columnar grains forming dense clusters spacing with several-μm gaps among grain clusters. The characteristics of the columnar grains disappeared after HIPIB irradiation at the ion current densities of 100-200 A/cm2, and the irradiated surface presented a smoothed, densified feature after the remelting and ablation due to the HIPIB irradiation. The thickness of the densified layer is about 1 μm. After oxidation with 15 cycles at 1050 °C ×1 h, the oxidation kinetics curves of the as-deposited and irradiated TBCs showed a parabolic shape. The weight gain of original sample is about 0.8-0.9 mg/cm2, while the values of the HIPIB-irradiated TBCs decreased to some extent. The lowest weight gain is obtained for the irradiated TBCs at 200 A/cm2 with one shot, being 0.3-0.4 mg/cm2, and those at 100 A/cm2 have a medium weight gain of 0.6-0.7 mg/cm2. The cross-sectional morphologies of HIPIB-irradiated TBCs show less oxidation of the NiCoCrAlY bonding layer, with a thinner thermally grown oxide (TGO) layer. The morphology observation is consistent with the results of cyclic oxidation test. It is found that the inward diffusion of oxygen through TBCs can be significantly impeded by the densified top layer by the HIPIB irradiation, thus limiting the oxidation of the bonding layer, improving the overall oxidation resistance of the irradiated TBCs.

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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