• Title/Summary/Keyword: Yttria

Search Result 347, Processing Time 0.031 seconds

Synthesis of Yttria Stabilized Zirconia Powder with Rare Earth Using Oxalate Method (옥살산법을 이용하여 희토류를 첨가한 안정화 지르코니아 분말 합성)

  • Nam, Jeong Sic;Lee, Ji-Sun;Lee, Young-Jin;Jeon, Dae-Woo;Kim, Sun-Woog;Ra, Yong-Ho;Kim, Sae-Hoon;Kim, Jin-Ho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.32 no.2
    • /
    • pp.174-177
    • /
    • 2019

  • The traditional yttria-stabilized zirconia (YSZ) used in thermal barrier coatings has a limited operating temperature owing to densification and volume changes at high temperatures. A $(La_{1-x}Y_x)_2Zr_2O_7$ sintered compound was prepared by the co-precipitation and oxalate methods, by adding lanthanum zirconate to yttria. The thermal properties and crystallinity obtained by the two different methods were compared. Both methods yielded pyrochlore structures, and the oxalate method confirmed phases at low temperatures. The thermal conductivity of the sintered bulk prepared by co-precipitation was 0.93 W/mK, while that prepared by the oxalate method was 0.85 W/mK. These values are superior to that of 4YSZ at $1,000^{\circ}C$, which is widely used in industries.

  • https://doi.org/10.4313/JKEM.2019.32.2.174 인용 PDF KSCI HTML

Neutron Diffraction Study on the Crystal Structure of Yttria-Stabilized Zirconium Oxide (중성자회절법을 이용한 이트리아 저코니아의 결정구조 연구)

  • Jin-Ho Lee;Chang-Hee Lee;Won-Sa Kim
    • Journal of the Mineralogical Society of Korea
    • /
    • v.13 no.3
    • /
    • pp.164-170
    • /
    • 2000

  • Neutron single crystal and powder diffraction techniques have been applied to the structure analysis of yttria-stabilized zirconium, Z $r_{0.73}$ $Y_{0.27}$ $O_{1.87}$., prepared by the skull-melting method. The crystal structure has been determined to be cubic symmetry, space group Fm/equation omitted/ with a=5.155(2)$\AA$, V=136.99(5)$\AA$, Z=4, and R(F)=5.65%, $\omega$R(I)=10.57% for 70 integrated intensities of Bragg Peaks observed from single crystal of Z $r_{0.73}$ $Y_{0.27}$ $O_{1.87}$. The stabilizer atoms randomly occupy the zirconium sites and there are displacements of oxygen atoms with amplitudes of $\Delta$/a~0.033 and 0.11 along <110> and <100> directions from the ideal positions of the fluorite structure, respectively. There are no significant differences in crystallographic data between the single crystal and powder studies. Diffraction pattern after Rietveld refinement, using neutron powder data, has shown the evidence of a tetragonal impurity phase, or a slight tetragonal distortion.

  • PDF