Comment on twinning in YNbO sub 4

Journal Article · Wed Apr 01 00:00:00 EST 1992 · Journal of the American Ceramic Society; (United States)

DOI:https://doi.org/10.1111/j.1151-2916.1992.tb04185.x· OSTI ID:5102435

Tsunekawa, S ^[1]

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1. Inst. for Materials Science, Tohoku Univ., Sendai, Miyagi 980 (JP)

The paper contains statements about an analogue of ZrO{sub 2} and the twins. The analogue is suggestive in connection with yttria-partially-stabilized zirconia, but an error is found in the description of the twins in YNbO{sub 4}. Because YNbO{sub 4} performs a pure, uncoupled ferroelastic transition (thermoelastic martensitic transformation), the composition plane is determined by the following formulas 4/mF2/m: x = pz and x = {minus}z/p, p = (b + (a{sup 2} + b{sup 2}){sup 1/2})/a a = (x{sub 33} {minus} x{sub 11})/2, b = {minus} tan ({beta} {minus} 90{degrees})/2) x{sub 11} = (a{sup I} {minus} a{sub 0})/a{sub 0}, x{sub 33} = (c{sup 1} {minus} a{sub 0})/a{sub 0} where a{sub 0} is the lattice parameter of a in the tetragonal phase, and a{sup I} and c{sup I} are the parameters of a and c, respectively, in the monoclinic phase represented by the I-lattice. The value of p at room temperature can be estimated by using the parameters included in this paper.

• OSTI ID: 5102435
• Journal Information: Journal of the American Ceramic Society; (United States), Vol. 75:4; ISSN 0002-7820
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
NIOBATES
TWINNING
YTTRIUM COMPOUNDS
CHEMICAL COMPOSITION
CRYSTAL STRUCTURE
LATTICE PARAMETERS
PHASE STABILITY
TETRAGONAL LATTICES
CRYSTAL LATTICES
NIOBIUM COMPOUNDS
OXYGEN COMPOUNDS
REFRACTORY METAL COMPOUNDS
STABILITY
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies