Synthesis of nanocrystalline La sub(2O) sub(3)-Y sub(2O) sub(3)-ZrO sub(2 solid solutions by hydrothermal method: A crystal growth and structural study)

• Published in: Journal of crystal growth 2011-11, Vol.335 (1), p.165-171
• Main Authors: Wang, Chunjie, Wang, Yue, Cheng, Yongliang, Zhu, Ling, Zou, Binglin, Zhao, Yu, Huang, Wenzhi, Fan, Xizhi, Khan, Zuhair Subhani, Cao, Xueqiang
• Format: Article
• Language: English
• Subjects: Crystal growth; Nanocomposites; Nanocrystals; Nanomaterials; Nanostructure; Phase transformations; Scanning electron microscopy
• ISSN: 0022-0248
• DOI: 10.1016/j.jcrysgro.2011.09.026

Well-size-distributed nanopowders of lanthana-yttria-zirconia ternary oxide were synthesized by hydrothermal method. The effects of La sub(2O) sub(3) on crystal growth and phase transition of YSZ nanocrystallite were investigated in detail with 8La sub(2O) sub(3)-8YSZ as an example. X-ray Diffraction (XRD), Thermogravimetric analysis (TG) and Differential Scanning Calorimeter analysis (DSC), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM) and High Resolution Transmission Electron Microscopy (HRTEM) were applied to characterize the phase formation, thermal decomposition and morphology of nanopowders. The XRD results indicate that 8La sub(2O) sub(3)-8YSZ is composed of both the face-centered cubic (ZrO sub(2) and pyrochlore (La) sub(2)Zr sub(2O) sub(7), LZ) structures. The average crystallite size obtained from TEM observation is 5-7 nm. The sample has a specific surface area of 201.2 m super(2 g) super(-)1, which is obviously higher than that of 8YSZ (145.9 m super(2 g) super(-)1). Moreover, the effective activation energy (Q) of crystal growth of 8La sub(2O) sub(3)-8YSZ and 8YSZ can be divided into two stages: below 900 degree C, Q sub(8YSZ=5.68 kJ mol) super(-)1 and [inline image]; in the range of 900-1300 degree C, Q sub(8YSZ=53.2 kJ mol) super(-)1 and [inline image].