Synthesis, characterization and sintering of Gd2Hf2O7 powders synthesized by solid state displacement reaction at low temperature

被引：19

作者：

Matovic, Branko ^{[1
]}

Maletaskic, Jelena ^{[1
,2
]}

Bucevac, Dusan ^{[1
]}

Zagorac, Jelena ^{[1
]}

Fajar, Muhammad ^{[2
]}

Yoshida, Katsumi ^{[2
]}

Yano, Toyohiko ^{[2
]}

机构：

[1] Univ Belgrade, Inst Nucl Sci Vinca, Ctr Excellence CextremeLab Vinca, Mike Petrovica Alasa 12-14, Belgrade 11000, Serbia

[2] Tokyo Inst Technol, Inst Innovat Res, Lab Adv Nucl Energy, Meguro Ku, 2-12-1 Ookayama, Tokyo 1528550, Japan

来源：

CERAMICS INTERNATIONAL | 2018年 / 44卷 / 14期

关键词：

Pyrochlore; Gd2Hf2O7; Low-temperature synthesis; Phase evolution; Sinterability; Thermal conductivity; PYROCHLORE; CONDUCTIVITY; CALCINATION; LA2ZR2O7; GD;

D O I：

10.1016/j.ceramint.2018.06.138

中图分类号：

TQ174 [陶瓷工业]; TB3 [工程材料学];

学科分类号：

0805 ; 080502 ;

摘要：

Pyrochlore compound (Gd2Hf2O7) powder was prepared by reacting gadolinium nitrate and hafnium chloride with NaOH during solid state displacement reaction at low temperature (SSDR). The SSDR process at room temperature initially yielded amorphous powders, which crystallized after subsequent calcination to form crystalline ceramics. The formation of crystalline Gd2Hf2O7 took place at temperature as low as 600 degrees C. The phase evolution with thermal treatment as well as powder properties such as crystallite size, lattice strain and lattice parameter were studied by X-ray powder diffraction (XRPD) at room temperature. High-density ceramic pellets free of any additives were obtained after compaction of the obtained powders and subsequent sintering at 1600 degrees C for 4 h in air. Rietveld analysis of X-ray diffraction (XRD) pattern of sintered sample showed that the unit cell parameter of the obtained Gd2Hf2O7 is 10.5501 (2) angstrom with x value = 0.345(2) in Wyckoff positions, indicating small distortion of octahedra. Hardness of the sintered samples was found to be 7.1 GPa. The thermal conductivity measurements performed in temperature range from room temperature to 1000 degrees C showed that thermal diffusivity of sintered samples was between 0.5 and 1 mm(2)/s whereas thermal conductivity was between 4 and 7 W/(m K).

引用

页码：16972 / 16976

页数：5

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