Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “La-Yb”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Chemical durability and surface alteration of lanthanide zirconates (A 2 Zr 2 O 7 : A = La-Yb)

Chemical durability of lanthanide zirconates (A 2 Zr 2 O 7 ) (A = La-Yb) under near-field environments is important for evaluating their application as potential nuclear waste forms. In this work, A 2 Zr 2 O 7 (A = La-Yb) are synthesized by spark plasma sintering with controlled microstructure and their chemical durability are evaluated in a nitric acid solution (pH = 1). Scanning transmission electron microscopy analysis reveals an amorphous passivation film either enriched with Zr or lanthanide. The complex chemistry of the passivation films can be correlated with a transition in corrosion mechanisms from a preferential release of lanthanide in La 2 Zr 2 O 7 to a preferential release of Zr in Er 2 Zr 2 O 7 and Yb 2 Zr 2 O 7 . These results suggest a dominant mechanism of incongruent dissolution and surface reorganization for the formation of passivation films. Strong correlations are identified between the leaching rates and cation ionic size, ionic potential, electronegativity differences between A-site cation and Zr, and bonding valence sum of oxygen, suggesting important impacts of structural and bonding characteristics in controlling chemical durability of lanthanide zirconates.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on La3Yb by Materials Project

YbLa3 is Copper-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Yb is bonded to twelve La atoms to form YbLa12 cuboctahedra that share corners with four equivalent YbLa12 cuboctahedra, corners with eight equivalent LaLa8Yb4 cuboctahedra, edges with eight equivalent YbLa12 cuboctahedra, edges with sixteen equivalent LaLa8Yb4 cuboctahedra, faces with four equivalent YbLa12 cuboctahedra, and faces with fourteen LaLa8Yb4 cuboctahedra. There are four shorter (3.74 Å) and eight longer (3.75 Å) Yb–La bond lengths. There are two inequivalent La sites. In the first La site, La is bonded to four equivalent Yb and eight La atoms to form LaLa8Yb4 cuboctahedra that share corners with twelve equivalent LaLa8Yb4 cuboctahedra, edges with eight equivalent YbLa12 cuboctahedra, edges with sixteen LaLa8Yb4 cuboctahedra, faces with four equivalent YbLa12 cuboctahedra, and faces with fourteen LaLa8Yb4 cuboctahedra. There are four shorter (3.74 Å) and four longer (3.75 Å) La–La bond lengths. In the second La site, La is bonded to four equivalent Yb and eight equivalent La atoms to form LaLa8Yb4 cuboctahedra that share corners with four equivalent LaLa8Yb4 cuboctahedra, corners with eight equivalent YbLa12 cuboctahedra, edges with twenty-four LaLa8Yb4 cuboctahedra, faces with six equivalent YbLa12 cuboctahedra, and faces with twelve LaLa8Yb4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La3Yb by Materials Project

YbLa3 is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Yb is bonded to twelve La atoms to form YbLa12 cuboctahedra that share corners with six equivalent YbLa12 cuboctahedra, corners with twelve LaLa8Yb4 cuboctahedra, edges with eighteen LaLa8Yb4 cuboctahedra, faces with eight equivalent YbLa12 cuboctahedra, and faces with twelve LaLa8Yb4 cuboctahedra. There are six shorter (3.74 Å) and six longer (3.80 Å) Yb–La bond lengths. There are three inequivalent La sites. In the first La site, La is bonded to four equivalent Yb and eight La atoms to form LaLa8Yb4 cuboctahedra that share corners with four equivalent YbLa12 cuboctahedra, corners with fourteen LaLa8Yb4 cuboctahedra, edges with six equivalent YbLa12 cuboctahedra, edges with twelve LaLa8Yb4 cuboctahedra, faces with four equivalent YbLa12 cuboctahedra, and faces with sixteen LaLa8Yb4 cuboctahedra. There are a spread of La–La bond distances ranging from 3.72–3.83 Å. In the second La site, La is bonded to four equivalent Yb and eight La atoms to form LaLa8Yb4 cuboctahedra that share corners with four equivalent YbLa12 cuboctahedra, corners with fourteen LaLa8Yb4 cuboctahedra, edges with six equivalent YbLa12 cuboctahedra, edges with twelve LaLa8Yb4 cuboctahedra, faces with four equivalent YbLa12 cuboctahedra, and faces with sixteen LaLa8Yb4 cuboctahedra. There are a spread of La–La bond distances ranging from 3.72–3.83 Å. In the third La site, La is bonded to four equivalent Yb and eight La atoms to form LaLa8Yb4 cuboctahedra that share corners with four equivalent YbLa12 cuboctahedra, corners with fourteen LaLa8Yb4 cuboctahedra, edges with six equivalent YbLa12 cuboctahedra, edges with twelve LaLa8Yb4 cuboctahedra, faces with four equivalent YbLa12 cuboctahedra, and faces with sixteen LaLa8Yb4 cuboctahedra. There are a spread of La–La bond distances ranging from 3.72–3.83 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaYb3 by Materials Project

Yb3La is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent Yb sites. In the first Yb site, Yb is bonded in a distorted body-centered cubic geometry to four equivalent Yb and four equivalent La atoms. All Yb–Yb bond lengths are 3.70 Å. All Yb–La bond lengths are 3.70 Å. In the second Yb site, Yb is bonded in a distorted body-centered cubic geometry to eight equivalent Yb atoms. La is bonded in a distorted body-centered cubic geometry to eight equivalent Yb atoms.

36 MATERIALS SCIENCE↗