Effects of Yb3+ doping on phase structure,thermal conductivity and fracture toughness of (Nd1-xYbx)2Zr2O7 |
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Authors: | Yang Wu Lei Zheng Wenting He Jian He Hongbo Guo |
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Affiliation: | 1. School of Materials Science and Engineering, Beihang University, No. 37 Xueyuan Road, Beijing 100191, China;2. Key Laboratory of High-Temperature Structure Materials and Protective Coatings (Ministry of Industry and Information Technology), Beihang University, No. 37 Xueyuan Road, Beijing 100191, China |
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Abstract: | To investigate the effects of Yb3+ doping on phase structure, thermal conductivity and fracture toughness of bulk Nd2Zr2O7, a series of (Nd1-xYbx)2Zr2O7 (x?=?0, 0.2, 0.4, 0.6, 0.8, 1.0) ceramics were synthesized using a solid-state reaction sintering method at 1600?°C for 10?h. The phase structures were sensitive to the Yb3+ content. With increasing doping concentration, a pyrochlore-fluorite transformation of (Nd1-xYbx)2Zr2O7 ceramics occurred. Meanwhile, the ordering degree of crystal structure decreased. The substitution mechanism of Yb3+ doping was confirmed by analyzing the lattice parameter variation and chemical bond of bulk ceramics. The thermal conductivities of (Nd1-xYbx)2Zr2O7 ceramics decreased first and then increased with the increase of Yb3+ content. The lowest thermal conductivity of approximately 1.2?W?m?1 K?1 at 800?°C was attained at x?=?0.4, around 20% lower than that of pure Nd2Zr2O7. Besides, the fracture toughness reached a maximum value of ~1.59?MPa?m1/2 at x?=?0.8 but decreased with further increasing Yb3+ doping concentration. The mechanism for the change of fracture toughness was discussed to result from the lattice distortion and structure disorder caused by Yb3+ doping. |
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Keywords: | Phase structure Thermal conductivity Fracture toughness |
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