Lan Wang,Xiaoyan Shu,Facheng Yi,Dadong Shao,Kuibao Zhang,Haibin Zhang,Xirui Lu
A series of Nd and Ce co-doped Gd 2- x Nd x Zr 2- y Ce y O 7 (0.0 ≤ x , y ≤ 2.0) ceramics were rapidly fabricated through spark plasma sintering (SPS) within 3 min. The effects of Nd and Ce contents on the phase composition, lattice parameter , active modes, microtopography and microstructure have been investigated in detail. XRD studies reveal that the compositions corresponding to 0.0 ≤ y ≤ 1.0 show a single phase and beyond 1.0 exhibit multiphase. The lattice parameters increase with elevated Nd and Ce content. The grains are densely packed on each other with cube-like shape, and the elements are almost homogeneously distributed in the compound. This synthetic method provides a simple pathway for the preparation of highly densified single phase ceramic at 1600–1700 ℃ for 3 min under pressure of 80 MPa.
Jin Wang,Junxia Wang,Yibing Zhang,Yuxiang Li,Yuancheng Teng,Zhe Wang,Hongbin Tan
A series of Nd and Ce co-doped (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) pyrochlores were synthesized by flux method at 900–1000 °C using nitrates as starting materials and a small amount of NaF as fluxing agent . The influences of contents of Nd/Ce, fluxing agent and reaction temperature on the phase structure of the pyrochlores were systematically investigated by X-ray diffraction (XRD) and Raman spectroscopy (Raman). The chemical stability of Nd and Ce co-doped pyrochlore bulk ceramics was also evaluated. XRD and Raman results showed that the crystalline phase of (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 (0 ≤ x ≤ 1) pyrochlores always remained a single disordered defect-fluorite structure for any x value. XRD, Raman spectrum and SEM-EDX results revealed that the Nd and Ce could be co-doped at the Gd-site and Zr-site of the Gd 2 Zr 2 O 7 pyrochlore structure, respectively. The normalized release rates of Gd, Zr, Nd and Ce in (Gd 1−x Nd x ) 2 (Zr 1−x Ce x ) 2 O 7 pyrochlore bulk ceramics (x = 0.25, 0.5 and 0.75) remained relatively constant in a low value below 10 −4 g m −2 d −1 at 90 °C for 7 days, exhibiting superior chemical stability.
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