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226 records · Page 13
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on YbSiPt by Materials Project

YbPtSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Yb2+ is bonded in a 4-coordinate geometry to six equivalent Si4- atoms. There are a spread of Yb–Si bond distances ranging from 3.03–3.24 Å. Pt2+ is bonded to four equivalent Si4- atoms to form a mixture of distorted edge and corner-sharing PtSi4 trigonal pyramids. There are a spread of Pt–Si bond distances ranging from 2.48–2.58 Å. Si4- is bonded in a 4-coordinate geometry to six equivalent Yb2+ and four equivalent Pt2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbSm3S4 by Materials Project

YbSm3S4 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Yb2+ is bonded to six equivalent S2- atoms to form YbS6 octahedra that share corners with six equivalent SmS6 octahedra, edges with six equivalent YbS6 octahedra, and edges with six equivalent SmS6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Yb–S bond lengths are 2.81 Å. There are two inequivalent Sm2+ sites. In the first Sm2+ site, Sm2+ is bonded to six S2- atoms to form SmS6 octahedra that share corners with three equivalent YbS6 octahedra, corners with three equivalent SmS6 octahedra, edges with three equivalent YbS6 octahedra, and edges with nine SmS6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. There are three shorter (2.81 Å) and three longer (2.87 Å) Sm–S bond lengths. In the second Sm2+ site, Sm2+ is bonded to six equivalent S2- atoms to form a mixture of edge and corner-sharing SmS6 octahedra. The corner-sharing octahedral tilt angles are 1°. All Sm–S bond lengths are 2.84 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Yb2+ and three equivalent Sm2+ atoms to form a mixture of edge and corner-sharing SYb3Sm3 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the second S2- site, S2- is bonded to six Sm2+ atoms to form a mixture of edge and corner-sharing SSm6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb3Si11Pt23 by Materials Project

Yb3Pt23Si11 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Yb2+ is bonded to eight equivalent Pt+1.83- atoms to form distorted corner-sharing YbPt8 cuboctahedra. All Yb–Pt bond lengths are 3.16 Å. There are four inequivalent Pt+1.83- sites. In the first Pt+1.83- site, Pt+1.83- is bonded in a distorted square co-planar geometry to four equivalent Si+3.27+ atoms. All Pt–Si bond lengths are 2.59 Å. In the second Pt+1.83- site, Pt+1.83- is bonded in a 5-coordinate geometry to two equivalent Yb2+ and three Si+3.27+ atoms. There are a spread of Pt–Si bond distances ranging from 2.43–2.47 Å. In the third Pt+1.83- site, Pt+1.83- is bonded to four Si+3.27+ atoms to form a mixture of edge and corner-sharing PtSi4 tetrahedra. There are one shorter (2.41 Å) and three longer (2.50 Å) Pt–Si bond lengths. In the fourth Pt+1.83- site, Pt+1.83- is bonded to four Si+3.27+ atoms to form a mixture of distorted edge and corner-sharing PtSi4 tetrahedra. All Pt–Si bond lengths are 2.52 Å. There are three inequivalent Si+3.27+ sites. In the first Si+3.27+ site, Si+3.27+ is bonded in a 7-coordinate geometry to seven Pt+1.83- atoms. In the second Si+3.27+ site, Si+3.27+ is bonded in a body-centered cubic geometry to eight Pt+1.83- atoms. In the third Si+3.27+ site, Si+3.27+ is bonded in a 7-coordinate geometry to seven Pt+1.83- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbSm4S5 by Materials Project

YbSm4S5 is Caswellsilverite-like structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Yb2+ is bonded to six equivalent S2- atoms to form YbS6 octahedra that share corners with six equivalent SmS6 octahedra, edges with six equivalent YbS6 octahedra, and edges with six equivalent SmS6 octahedra. The corner-sharing octahedral tilt angles are 2°. All Yb–S bond lengths are 2.81 Å. There are two inequivalent Sm2+ sites. In the first Sm2+ site, Sm2+ is bonded to six S2- atoms to form SmS6 octahedra that share corners with three equivalent YbS6 octahedra, corners with three equivalent SmS6 octahedra, edges with three equivalent YbS6 octahedra, and edges with nine SmS6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. There are three shorter (2.80 Å) and three longer (2.89 Å) Sm–S bond lengths. In the second Sm2+ site, Sm2+ is bonded to six S2- atoms to form a mixture of edge and corner-sharing SmS6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.80 Å) and three longer (2.86 Å) Sm–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Yb2+ and three equivalent Sm2+ atoms to form a mixture of edge and corner-sharing SYb3Sm3 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the second S2- site, S2- is bonded to six equivalent Sm2+ atoms to form a mixture of edge and corner-sharing SSm6 octahedra. The corner-sharing octahedral tilt angles are 2°. In the third S2- site, S2- is bonded to six Sm2+ atoms to form a mixture of edge and corner-sharing SSm6 octahedra. The corner-sharing octahedra tilt angles range from 2–3°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb2H6Ru by Materials Project

Yb2RuH6 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Yb2+ is bonded to twelve equivalent H1- atoms to form YbH12 cuboctahedra that share corners with twelve equivalent YbH12 cuboctahedra, faces with six equivalent YbH12 cuboctahedra, and faces with four equivalent RuH6 octahedra. All Yb–H bond lengths are 2.51 Å. Ru2+ is bonded to six equivalent H1- atoms to form RuH6 octahedra that share faces with eight equivalent YbH12 cuboctahedra. All Ru–H bond lengths are 1.72 Å. H1- is bonded to four equivalent Yb2+ and one Ru2+ atom to form a mixture of corner, edge, and face-sharing HYb4Ru square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb(Ni2As)2 by Materials Project

YbNi4As2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Yb2+ is bonded to six equivalent As3- atoms to form a mixture of corner and edge-sharing YbAs6 octahedra. The corner-sharing octahedral tilt angles are 40°. There are two shorter (2.88 Å) and four longer (2.90 Å) Yb–As bond lengths. Ni1+ is bonded in a trigonal non-coplanar geometry to three equivalent As3- atoms. There are two shorter (2.38 Å) and one longer (2.40 Å) Ni–As bond lengths. As3- is bonded in a 9-coordinate geometry to three equivalent Yb2+ and six equivalent Ni1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbSiO3 by Materials Project

YbSiO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Yb2+ is bonded to twelve equivalent O2- atoms to form YbO12 cuboctahedra that share corners with twelve equivalent YbO12 cuboctahedra, faces with six equivalent YbO12 cuboctahedra, and faces with eight equivalent SiO6 octahedra. All Yb–O bond lengths are 2.52 Å. Si4+ is bonded to six equivalent O2- atoms to form SiO6 octahedra that share corners with six equivalent SiO6 octahedra and faces with eight equivalent YbO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Si–O bond lengths are 1.78 Å. O2- is bonded in a distorted linear geometry to four equivalent Yb2+ and two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbC6 by Materials Project

YbC6 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Yb2+ is bonded to twelve equivalent C+0.33- atoms to form edge-sharing YbC12 cuboctahedra. All Yb–C bond lengths are 2.63 Å. C+0.33- is bonded in a 5-coordinate geometry to two equivalent Yb2+ and three equivalent C+0.33- atoms. All C–C bond lengths are 1.45 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb(CuS)2 by Materials Project

Yb(CuS)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Yb2+ is bonded to six equivalent S2- atoms to form YbS6 octahedra that share corners with twelve equivalent CuS4 tetrahedra, edges with six equivalent YbS6 octahedra, and edges with six equivalent CuS4 tetrahedra. All Yb–S bond lengths are 2.78 Å. Cu1+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with six equivalent YbS6 octahedra, corners with six equivalent CuS4 tetrahedra, edges with three equivalent YbS6 octahedra, and edges with three equivalent CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–54°. There are three shorter (2.36 Å) and one longer (2.42 Å) Cu–S bond lengths. S2- is bonded to three equivalent Yb2+ and four equivalent Cu1+ atoms to form a mixture of distorted edge and corner-sharing SYb3Cu4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗
NASA NTRS2015

Kinetic Monte Carlo Simulation of Oxygen Diffusion in Ytterbium Disilicate

Silicon-based ceramic components for next-generation jet turbine engines offer potential weight savings, as well as higher operating temperatures, both of which lead to increased efficiency and lower fuel costs. Silicon carbide (SiC), in particular, offers low density, good strength at high temperatures, and good oxidation resistance in dry air. However, reaction of SiC with high-temperature water vapor, as found in the hot section of jet turbine engines in operation, can cause rapid surface recession, which limits the lifetime of such components. Environmental Barrier Coatings (EBCs) are therefore needed if long component lifetime is to be achieved. Rare earth silicates such as Yb2Si2O7 and Yb2SiO5 have been proposed for such applications; in an effort to better understand diffusion in such materials, we have performed kinetic Monte Carlo (kMC) simulations of oxygen diffusion in Ytterbium disilicate, Yb2- Si2O7. The diffusive process is assumed to take place via the thermally activated hopping of oxygen atoms among oxygen vacancy sites or among interstitial sites. Migration barrier energies are computed using density functional theory (DFT).

Computer Simulation↗