Wear Characteristics of Plasma-Sprayed Nanostructured Yttria Partially Stabilized Zirconia Coatings

2005 ◽  
Vol 14 (4) ◽  
pp. 518-523 ◽  
Author(s):  
Shunyan Tao ◽  
Bo Liang ◽  
Chuanxian Ding ◽  
Hanlin Liao ◽  
Christian Coddet
Keyword(s):  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
Wear Characteristics ◽  
Yttria Partially Stabilized Zirconia ◽  
Plasma Sprayed

Microstructural Investigations of Plasma Sprayed Yttria Partially Stabilized Zirconia TBC: in Relation to Thermomechanical Resistance and High Temperature Oxidation Mechanisms

1992 ◽  
Author(s):  
S. Alperine ◽  
L. Lelait
Keyword(s):  
High Temperature ◽  
Chemical Reduction ◽  
Diffusion Mechanism ◽  
Cubic Phase ◽  
High Temperature Annealing ◽  
Stabilized Zirconia ◽  
Temperature Oxidation ◽  
Partially Stabilized Zirconia ◽  
Yttria Partially Stabilized Zirconia ◽  
Plasma Sprayed

This study deals with microstructural investigations of plasma sprayed yttria partially stabilized zirconia thermal barrier coatings, performed by classical and analytical transmission electron microscopy. The aim of the study was to determine eventual relationships between coating microstructure and toughness. The ceramic/metal interface which plays an important role during TBC thermomechanical sollicitation, has also been studied. In the 6 to 8 weight % Y2O3 range, the metastable tetragonal t’ phase is observed, showing special faulted microstructural features, such as grain twinning and antiphase boundary planes. Moreover, after high temperature annealing in air, a very fine and stable precipitation of the equilibrium cubic phase appears. It is believed that these microstructural elements could act as crack deviation sites and enhance coatings intrinsic toughness. Microstructural investigations of the alumina scales grown during high temperature annealing reveal yttrium segregation at oxide grain boundaries as well as significant quantities of zirconium inside the alumina grains. The oxide growth seems to be dominated by a classical grain boundary oxygen diffusion mechanism. The presence of zirconium inside the alumina grains suggests that Al2O3 also partially forms by chemical reduction of ZrO2 by Al.

Microstructural Investigations of Plasma-Sprayed Yttria Partially Stabilized Zirconia TBC (In Relation to Thermomechanical Resistance and High-Temperature Oxidation Mechanisms)

1994 ◽  
Vol 116 (1) ◽  
pp. 258-265 ◽  
Author(s):  
S. Alpe´rine ◽  
L. Lelait
Keyword(s):  
High Temperature ◽  
Chemical Reduction ◽  
Diffusion Mechanism ◽  
Cubic Phase ◽  
High Temperature Annealing ◽  
Stabilized Zirconia ◽  
Temperature Oxidation ◽  
Partially Stabilized Zirconia ◽  
Yttria Partially Stabilized Zirconia ◽  
Plasma Sprayed

This study deals with microstructural investigations of plasma-sprayed yttria partially stabilized zirconia thermal barrier coatings, performed by classical and analytical transmission electron microscopy. The aim of the study was to determine eventual relationships between coating microstructure and toughness. The ceramic/metal interface, which plays an important role during TBC thermomechanical solicitation, has also been studied. In the 6–8 wt. percent Y2O3 range, the metastable tetragonal t′ phase is observed, showing special faulted microstructural features, such as grain twinning and antiphase boundary planes. Moreover, after high-temperature annealing in air, a very fine and stable precipitation of the equilibrium cubic phase appears. It is believed that these microstructural elements could act as crack deviation sites and enhance the coatings’ intrinsic toughness. Microstructural investigations of the alumina scales grown during high-temperature annealing reveal yttrium segregation at oxide grain boundaries as well as significant quantities of zirconium inside the alumina grains. The oxide growth seems to be dominated by a classical grain boundary oxygen diffusion mechanism. The presence of zirconium inside the alumina grains suggests that Al2O3 also partially forms by chemical reduction of ZrO2 by Al.

Nitriding of yttria-stabilized zirconia in atmospheric pressure microwave plasma

2009 ◽  
Vol 24 (6) ◽  
pp. 2021-2028 ◽  
Author(s):  
R. Milani ◽  
R.P. Cardoso ◽  
T. Belmonte ◽  
C.A. Figueroa ◽  
C.A. Perottoni ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Atmospheric Pressure ◽  
Microwave Plasma ◽  
Plasma Nitriding ◽  
Nitrided Layer ◽  
Zirconium Nitride ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
X Ray ◽  
Yttria Partially Stabilized Zirconia

High temperature plasma nitriding of yttria-partially-stabilized zirconia in atmospheric pressure microwave plasma was investigated. The morphological, mechanical, and physicochemical characteristics of the resulting nitrided layer were characterized by different methods, such as optical and scanning electron microscopy, microindentation, x-ray diffraction, narrow resonant nuclear reaction profiling, secondary neutral mass spectrometry, and x-ray photoelectron spectroscopy, aiming at investigating the applicability of this highly efficient process for nitriding of ceramics. The structure of the plasma nitrided layer was found to be complex, composed of tetragonal and cubic zirconia, as well as zirconium nitride and oxynitride. The growth rate of the nitrided layer, 4 µm/min, is much higher than that obtained by any other previous nitriding process, whereas a typical 50% increase in Vickers hardness over that of yttria-partially-stabilized zirconia was observed.

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