準安定HfO_2-YO_<1.5>固溶体の格子定数と酸素の変位

概要

論文の詳細を見る
HfO_2-X mol% YO_<1.5> solid solutions (X=0-22) were prepared by arc melting to investigate the compositional dependence of the unit-cell parameters of diffusion-lessly formed metastable phases through X-ray powder diffraction measurements at room temperature. Unit-cell parameters of monoclinic and tetragonal phases of HfO_2-X mol% YO_<1.5>(X=0, 2, 4, 5, 6, 7, 8 and 9) were refined by the Rietveld analysis. The lattice parameter and oxygen displacement were estimated for samples of X=10 to 22 by the profile-fitting technique. In the monoclinic phase(0≨X≨7), the lattice parameter a increased, while the b and the β angle decreased with an increase of YO_<1.5> content. In the tetragonal phase, the lattice parameter a increased (6≨X<13), while the c and the axial ratio c/a_f decreased (7≨X<13) with increasing of YO_<1.5> content, and then a_f and c axes values coincided each other at X=13, where the suffix f denotes the distorted pseudo-fluorite cell. In the tetragonal hafnia (10≨X≨16), the oxygen displacement from the ideal fluorite site decreased with increasing of YO_<1.5< content. The HfO_2-13 mol% YO_<1.5> sample exhibited an axial ratio of unity within the experimental resolution, but showed 112_f reflection peak, strongly suggesting the existence of the t″-form, which is defined as a tetragonal phase with a c/a_f of unity. The t″-form is interpreted to appear in the compositional region of 13 to 16 mol% YO_<1.5>.
社団法人日本セラミックス協会の論文
1995-06-01

準安定HfO_2-YO_<1.5>固溶体の格子定数と酸素の変位

スポンサーリンク

概要

著者

関連論文

スポンサーリンク