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7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on FePO4 by Materials Project

FePO4 is quartz (alpha)-derived structured and crystallizes in the trigonal P3_121 space group. The structure is three-dimensional. Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent PO4 tetrahedra. There is two shorter (1.88 Å) and two longer (1.89 Å) Fe–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent FeO4 tetrahedra. All P–O bond lengths are 1.55 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FePO4 by Materials Project

FePO4 is quartz (alpha)-derived structured and crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent PO4 tetrahedra. There is three shorter (1.88 Å) and one longer (1.89 Å) Fe–O bond length. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent FeO4 tetrahedra. There is one shorter (1.54 Å) and three longer (1.55 Å) P–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FePO4 by Materials Project

FePO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four equivalent PO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.88–1.91 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four equivalent FeO4 tetrahedra. All P–O bond lengths are 1.55 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Fe3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FePO4 by Materials Project

FePO4 crystallizes in the trigonal R3 space group. The structure is three-dimensional. there are two inequivalent Fe3+ sites. In the first Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four PO4 tetrahedra. There is two shorter (1.88 Å) and two longer (1.91 Å) Fe–O bond length. In the second Fe3+ site, Fe3+ is bonded to four O2- atoms to form FeO4 tetrahedra that share corners with four PO4 tetrahedra. There is one shorter (1.88 Å) and three longer (1.89 Å) Fe–O bond length. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO4 tetrahedra. There is three shorter (1.55 Å) and one longer (1.56 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four FeO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Fe3+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Fe3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FePO4 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
NASA NTRS1987

Phase equilibria in the iron oxide-cobalt oxide-phosphorus oxide system

Two novel ternary compounds are noted in the present study of 1000 C solid-state equilibria in the Fe-Co-P-O system's Fe2O3-FePO4-Co3(Po4)2-CoO region: CoFe(PO4)O, which undergoes incongruent melting at 1130 C, and Co3Fe4(PO4)6, whose incongruent melting occurs at 1080 C. The liquidus behavior-related consequences of rapidly solidified cobalt ferrite formation from cobalt ferrite-phosphate melts are discussed with a view to spinel formation. It is suggested that quenching from within the spinel-plus-liquid region may furnish an alternative to quenching a homogeneous melt.

De Guire, Mark R.↗
NASA NTRS1997

The Effects of Acid Passivation, Tricresyl Phosphate Pre-Soak, and UV/Ozone Treatment on the Tribology of Perfluoropolyether-Lubricated 440C Stainless Steel Couples

The boundary-lubrication performance of perfluoropolyether (PFPE) thin films in the presence of passivated 440 C stainless steel is presented. The study utilized a standard ball-on-disc tribometer. Stainless steel surfaces were passivated with one of four techniques: 1) submersion in a chromic acid bath for 30 minutes at 46 C, 2) submersion in a chromic acid bath for 60 minutes at 56 C, 3) submersion in a tricresyl phosphate (TCP) bath for 2 days at 107 C, or 4) UV/Ozone treated for 15 minutes. After passivation, each disc had a 400 A film of PFPE (hexafluoropropene oxide) applied to it reproducibly (+/- 20%) and uniformly (+/- 15%) using a film deposition device. The lifetimes of these films were quantified by measuring the number of sliding wear cycles required to induce an increase in the friction coefficient from an initial value characteristic of the lubricated wear couple to a final, or failure value, characteristic of an unlubricated, unpassivated wear couple. The lubricated lifetime of the 440 C couple was not altered as a result of the various passivation techniques. The resulting surface chemistry of each passivation technique was examined using X-ray Photoelectron Spectroscopy (XPS). It was found that chromic acid passivation altered the Cr to Fe ratio of the surface. TCP passivation resulted in a FePO4 layer on the surface, while UV/Ozone passivation only removed the carbonaceous contamination layer. None of the passivation techniques were found to dramatically increase the oxide film thickness.

Shogrin, Bradley A.↗