Effects of Y sub(2)O sub(3) addition on the phase evolution and thermophysical properties of lanthanum zirconate

Lanthanum zirconate (La sub(2)Zr sub(2)O sub(7), LZ) powders with the addition of various Y sub(2)O sub(3) contents for potential thermal barrier coatings (TBCs) application were synthesized by solid-state reaction. The structure evolution, sintering-resistance and thermophysical properties of the s...

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Bibliographic Details
Published in:Journal of alloys and compounds 2009-07, Vol.480 (2), p.220-224
Main Authors: Xu, Zhenhua, He, Limin, Zhong, Xinghua, Zhang, Jiangfeng, Chen, Xiaolong, Ma, Hongmei, Cao, Xueqiang
Format: Article
Language:English
Subjects:
Ceramics
Density
Diffraction
Evolution
Lanthanum
Thermophysical properties
Yttrium oxide
Zirconates
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Summary:Lanthanum zirconate (La sub(2)Zr sub(2)O sub(7), LZ) powders with the addition of various Y sub(2)O sub(3) contents for potential thermal barrier coatings (TBCs) application were synthesized by solid-state reaction. The structure evolution, sintering-resistance and thermophysical properties of the synthesized powders and sintered ceramics were systematically studied. X-ray diffraction (XRD) results indicate that LZ containing 3-12 wt.% Y sub(2)O sub(3) mainly keeps a pyrochlore-type structure, and two new phases of LaYO sub(3) and Y sub(0.18)Zr sub(0.82)O sub(1.91) are also detected. Raman spectra confirm that the higher the Y sub(2)O sub(3) content, the easier is the formation of LaYO sub(3). With the increase of Y sub(2)O sub(3) content, the linear thermal expansion coefficients (TEC) of different La sub(2)O sub(3)-ZrO sub(2)-Y sub(2)O sub(3) ceramics may gradually decrease. Additionally, LZ ceramics doped with 3 wt.% Y sub(2)O sub(3) have the lowest relative density and the highest sintering-resistance among all samples, implying that it is the best candidate for TBCs among those samples in this investigation.
ISSN:0925-8388
DOI:10.1016/j.jallcom.2009.02.048