Evaluation of thermal conductivity of thermal barrier coating by a laser flash method and a differential scanning calorimeter

Author(s):  
Daeho Kim ◽  
Sungjun Lee ◽  
Suyong Kwon
Coatings ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 253 ◽  
Author(s):  
Qi Wang ◽  
Lei Guo ◽  
Zheng Yan ◽  
Fuxing Ye

TiO2 was doped into Er2O3-stabilized ZrO2 (ErSZ) to obtain desirable properties for thermal barrier coating (TBC) applications. The phase composition, thermal conductivity, and mechanical properties of TiO2-doped ErSZ were investigated. ErSZ had a non-transformable metastable tetragonal (t′) phase, the compound with 5 mol % TiO2 consisted of t′ and cubic (c) phases, while 10 mol % TiO2 doped ErSZ had t′, c, and about 3.5 mol % monoclinic (m) phases. Higher TiO2 doping contents caused more m phase, and the compounds were composed of t′ and m phases. When the dopant content was below 10 mol %, TiO2 doping could decrease the thermal conductivity and enhance the toughness of the compounds. At higher doping levels, the compounds exhibited an increased thermal conductivity and a reduction in the toughness, mainly attribable to the formation of the undesirable m phase. Hence, 10 mol % TiO2-doped ErSZ could be a promising candidate for TBC applications.


Author(s):  
Jianhua Yu ◽  
Huayu Zhao ◽  
Shunyan Tao ◽  
Xiaming Zhou ◽  
Chuanxian Ding

Plasma-sprayed thermal barrier coating (TBC) systems are widely used in gas turbine blades to increase turbine entry temperature (TET) and better efficiency. Yttria stabilized zirconia (YSZ) has been the conventional thermal barrier coating material because of its low thermal conductivity, relative high thermal expansion coefficient and good corrosion resistance. However the YSZ coatings can hardly fulfill the harsh requirements in future for higher reliability and the lower thermal conductivity at higher temperatures. Among the interesting TBC candidates, materials with pyrochlore structure show promising thermo-physical properties for use at temperatures exceeding 1200 °C. Sm2Zr2O7 bulk material does not only have high temperature stability, sintering resistance but also lower thermal conductivity and higher thermal expansion coefficient. The sintering characteristics of ceramic thermal barrier coatings under high temperature conditions are complex phenomena. In this paper, samarium zirconate (Sm2Zr2O7, SZ) powder and coatings were prepared by solid state reaction and atmosphere plasma spraying process, respectively. The microstructure development of coatings derived from sintering after heat-treated at 1200–1500 °C for 50 h have been investigated. The microstructure was examined by scanning electron microscopy (SEM) and the grain growth was analyzed in this paper as well.


1981 ◽  
Vol 20 (4) ◽  
pp. 333-336 ◽  
Author(s):  
Yutaka Tada ◽  
Makoto Harada ◽  
Masataka Tanigaki ◽  
Wataru Eguchi

1998 ◽  
Vol 7 (1) ◽  
pp. 43-46 ◽  
Author(s):  
A.J. Slifka ◽  
B.J. Filla ◽  
J.M. Phelps ◽  
G. Bancke ◽  
C.C. Berndt

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