scholarly journals Microstructural evolution and growth kinetics of thermally grown oxides in plasma sprayed thermal barrier coatings

2016 ◽  
Vol 26 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Xiaoju Liu ◽  
Teng Wang ◽  
Caicai Li ◽  
Zhenhuan Zheng ◽  
Qiang Li
Keyword(s):  
Thermal Barrier Coatings ◽  
Microstructural Evolution ◽  
Growth Kinetics ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Thermally Grown Oxides ◽  
Plasma Sprayed ◽  
Kinetics Of ◽  
Thermally Grown

MICROSTRUCTURAL EVOLUTION AND RESIDUAL STRESSES OF AIR-PLASMA SPRAYED THERMAL BARRIER COATINGS UNDER THERMAL EXPOSURE

2010 ◽  
Vol 17 (03) ◽  
pp. 337-343 ◽  
Author(s):  
JAE-YOUNG KWON ◽  
JAE-HYOUN KIM ◽  
SANG-YEOP LEE ◽  
YEON-GIL JUNG ◽  
HYUN CHO ◽  
...  
Keyword(s):  
Thermal Barrier Coatings ◽  
Microstructural Evolution ◽  
Thermal Exposure ◽  
Thermally Grown Oxide ◽  
Thermal Barrier ◽  
Air Plasma ◽  
Barrier Coatings ◽  
Before And After ◽  
Peak Areas ◽  
Plasma Sprayed

Microstructural evolution and fracture behavior of zirconia ( ZrO2 )-based thermal barrier coatings (TBCs) were investigated under thermal exposure. New ZrO 2 granule with 8 wt.% yttria ( Y2O3 ) with a deformed hollow morphology was developed through a spray drying process and employed to prepare TBCs. The thermal exposure tests were conducted at 1210°C with a dwell time of 100 h till 800 h. The residual stress at the interface between top coat and thermally grown oxide (TGO) layer was measured using a nanoindentation technique before and after thermal exposure. Vertical cracks on the top coat were newly formed and interlamellar cracks at the interface were enhanced after the thermal exposure of 800 h. Especially, partial delamination was observed at the interface after the thermal exposure of 800 h in TBC samples tested. The microstructural evolution in the top coat could be defined through load–displacement curves, showing a higher load or a less displacement after the thermal exposure of 800 h. The stress state was strongly dependent on the TGO geometry, resulting in the compressive stresses at the "valleys" or the "troughs," and the tensile stresses at the "crests" or peak areas, in the ranges of -500 to -75 MPa and of +168 to + 24 MPa, respectively. These stress terms incorporated with resintering during thermal exposure affected the mechanical properties such as hardness and elastic modulus of the top coat.

In-Plane Cracking Behavior Near and Away from Interface of Thermal Barrier Coatings and Thermally Grown Oxides

2000 ◽  
Vol 645 ◽  
Author(s):  
Z. Zhang ◽  
J. Kameda ◽  
A. H. Swanson ◽  
S. Sakurai
Keyword(s):  
Tensile Stress ◽  
Thermal Barrier Coatings ◽  
Thermal Barrier ◽  
Element Analysis ◽  
Cracking Behavior ◽  
Barrier Coatings ◽  
Thermally Grown Oxides ◽  
Out Of Plane ◽  
Point Bend ◽  
Thermally Grown

ABSTRACTThe initiation characteristics of in-plane cracks near and away from the interface of thermal barrier coatings (TBC) and thermally grown oxides (TGO) have been studied using a protruded four-point bend testing technique together with a finite element analysis. In-plane TBC cracks were initiated near and away from the TBC/TGO interface, respectively, in protruded specimens without and with grooved substrates. It was shown that the onset of in-plane TBC cracks near or away from the interface in the protruded TBC tests was controlled by the out-of-plane tensile stress but not by the principal tensile stress acting upon an inclined plane to the interface. The critical local tensile stress for the initiation of TBC cracks near the interface was found to be 20% lower than that away from the interface. The TBC cracking near and away from the TBC/TGO interface is discussed in light of the residual stress distribution through the TBC thickness.

Sign in / Sign up

Export Citation Format

Share Document