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Results for “Fe-Si-Zr”

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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Electronic Structure and Spin Correlations in Novel Magnetic Structures

The research has advanced understanding of the interrelation between the crystal structure and magnetism in several materials which are or can be of interest for the development of improved, specialized or more cost-effective permanent magnets, as well as in selected materials for biomedical and catalytic applications. Fundamental aspects of ferromagnetism were investigated for Mn-Ge, Co-V and Co-Ge nanoclusters and for melt-spun Co-Sn alloys. New solution-chemistry synthesis methods were designed and tested for Fe-Pt, Fe3C and Fe3O4 nanoparticles. Off-stoichiometric Laves phases in the Fe-Si-Zr, Fe-Nb and Fe-Ta systems, as well as Fe5(Si,Ge)B2 compounds were assessed as new rare-earth-free permanent magnet materials; all except the Fe-Si-Zr Laves phases were found to be promising enough to merit a further exploration. A new method for manufacturing rare-earth-free magnets based on the MnBi compound was developed; by purposely avoiding oxidation-sensitive fine single-crystalline powders, the new method yields magnets with a 50% larger energy storage capacity. Studies of rare-earth-lean permanent-magnet materials (lean compared to the currently predominant Nd-Fe-B materials) were focused on the tetragonal compound of the ThMn12 structure type and included both discovery and characterization of new formulations and exploration of new fabrication/processing techniques. Among the most significant achievements were successful preparation of a vanadium-lean SmFe11V compound, the first observation of thermomechanically induced texture in nanocrystalline Sm(Fe,V)12 alloys, and a breakthrough reduction-diffusion synthesis of Sm1-xZrx(Fe0.8Co0.2)11.2Ti0.8 single-crystal particles with a coercivity as high as 12.6 kOe. Several experiments aimed at improvement of the Nd-Fe-B magnet have also been undertaken including a five-fold increase of the coercivity through a grain-boundary diffusion treatment of a Nd10Fe84B6 nanocrystalline alloy.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr2Fe3Si by Materials Project

Zr2Fe3Si is Hexagonal Laves-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Zr is bonded in a 12-coordinate geometry to four equivalent Zr, nine equivalent Fe, and three equivalent Si atoms. There are one shorter (3.00 Å) and three longer (3.06 Å) Zr–Zr bond lengths. There are three shorter (2.90 Å) and six longer (2.91 Å) Zr–Fe bond lengths. All Zr–Si bond lengths are 2.93 Å. Fe is bonded to six equivalent Zr, four equivalent Fe, and two equivalent Si atoms to form FeZr6Fe4Si2 cuboctahedra that share corners with four equivalent SiZr6Fe6 cuboctahedra, corners with fourteen equivalent FeZr6Fe4Si2 cuboctahedra, edges with six equivalent FeZr6Fe4Si2 cuboctahedra, faces with six equivalent SiZr6Fe6 cuboctahedra, and faces with twelve equivalent FeZr6Fe4Si2 cuboctahedra. There are two shorter (2.45 Å) and two longer (2.54 Å) Fe–Fe bond lengths. Both Fe–Si bond lengths are 2.49 Å. Si is bonded to six equivalent Zr and six equivalent Fe atoms to form SiZr6Fe6 cuboctahedra that share corners with twelve equivalent FeZr6Fe4Si2 cuboctahedra, edges with six equivalent SiZr6Fe6 cuboctahedra, faces with two equivalent SiZr6Fe6 cuboctahedra, and faces with eighteen equivalent FeZr6Fe4Si2 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Zr4Fe4Si7 by Materials Project

Zr4Fe4Si7 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Zr2+ sites. In the first Zr2+ site, Zr2+ is bonded to seven Si+2.86- atoms to form ZrSi7 pentagonal bipyramids that share corners with eight equivalent FeSi6 octahedra, corners with eight ZrSi7 pentagonal bipyramids, an edgeedge with one ZrSi7 pentagonal bipyramid, faces with four equivalent FeSi6 octahedra, and faces with six ZrSi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 41–53°. There are a spread of Zr–Si bond distances ranging from 2.76–2.87 Å. In the second Zr2+ site, Zr2+ is bonded to seven Si+2.86- atoms to form ZrSi7 pentagonal bipyramids that share corners with eight equivalent FeSi6 octahedra, corners with eight ZrSi7 pentagonal bipyramids, edges with three equivalent ZrSi7 pentagonal bipyramids, faces with four equivalent FeSi6 octahedra, and faces with six ZrSi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 43–52°. There are a spread of Zr–Si bond distances ranging from 2.79–2.86 Å. Fe3+ is bonded to six Si+2.86- atoms to form distorted FeSi6 octahedra that share corners with six equivalent FeSi6 octahedra, corners with eight ZrSi7 pentagonal bipyramids, edges with three equivalent FeSi6 octahedra, faces with two equivalent FeSi6 octahedra, and faces with four ZrSi7 pentagonal bipyramids. The corner-sharing octahedra tilt angles range from 33–36°. There are a spread of Fe–Si bond distances ranging from 2.39–2.42 Å. There are four inequivalent Si+2.86- sites. In the first Si+2.86- site, Si+2.86- is bonded in a 10-coordinate geometry to eight Zr2+ and two equivalent Si+2.86- atoms. Both Si–Si bond lengths are 2.52 Å. In the second Si+2.86- site, Si+2.86- is bonded in a 6-coordinate geometry to one Zr2+, four equivalent Fe3+, and one Si+2.86- atom. The Si–Si bond length is 2.39 Å. In the third Si+2.86- site, Si+2.86- is bonded in a 12-coordinate geometry to four Zr2+ and four equivalent Fe3+ atoms. In the fourth Si+2.86- site, Si+2.86- is bonded in a 9-coordinate geometry to five Zr2+ and four equivalent Fe3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZrFe4Si by Materials Project

ZrFe4Si crystallizes in the cubic F-43m space group. The structure is three-dimensional. Zr is bonded in a 12-coordinate geometry to twelve equivalent Fe and four equivalent Si atoms. All Zr–Fe bond lengths are 2.78 Å. All Zr–Si bond lengths are 2.90 Å. Fe is bonded to three equivalent Zr, six equivalent Fe, and three equivalent Si atoms to form a mixture of edge, corner, and face-sharing FeZr3Fe6Si3 cuboctahedra. There are three shorter (2.34 Å) and three longer (2.40 Å) Fe–Fe bond lengths. All Fe–Si bond lengths are 2.78 Å. Si is bonded in a 4-coordinate geometry to four equivalent Zr and twelve equivalent Fe atoms.

36 MATERIALS SCIENCE↗