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All sourcesNASA NTRSDOE OSTI
NASA NTRS2013

Surface Temperature Measurements from a Stator Vane Doublet in a Turbine Engine Afterburner Flame using Ultra-Bright Cr-Doped GdAlO3 Thermographic Phosphor

Luminescence-based surface temperature measurements from an ultra-bright Cr-doped GdAlO3 perovskite (GAP:Cr) coating were successfully conducted on an air-film-cooled stator vane doublet exposed to the afterburner flame of a J85 test engine at University of Tennessee Space Institute (UTSI). The objective of the testing at UTSI was to demonstrate that reliable thermal barrier coating (TBC) surface temperatures based on luminescence decay of a thermographic phosphor could be obtained from the surface of an actual engine component in an aggressive afterburner flame environment and to address the challenges of a highly radiant background and high velocity gases. A high-pressure turbine vane doublet from a Honeywell TECH7000 turbine engine was coated with a standard electron-beam physical vapor deposited (EB-PVD) 200-m-thick TBC composed of yttria-stabilized zirconia (YSZ) onto which a 25-m-thick GAP:Cr thermographic phosphor layer was deposited by EB-PVD. The ultra-bright broadband luminescence from the GAP:Cr thermographic phosphor is shown to offer the advantage of over an order-of-magnitude greater emission intensity compared to rare-earth-doped phosphors in the engine test environment. This higher emission intensity was shown to be very desirable for overcoming the necessarily restricted probe light collection solid angle and for achieving high signal-to-background levels. Luminescence-decay-based surface temperature measurements varied from 500 to over 1000C depending on engine operating conditions and level of air film cooling.

Eldridge, Jeffrey I.↗
NASA NTRS2013

Cu-Cr-Nb-Zr Alloy for Rocket Engines and Other High-Heat- Flux Applications

Rocket-engine main combustion chamber liners are used to contain the burning of fuel and oxidizer and provide a stream of high-velocity gas for propulsion. The liners in engines such as the Space Shuttle Main Engine are regeneratively cooled by flowing fuel, e.g., cryogenic hydrogen, through cooling channels in the back side of the liner. The heat gained by the liner from the flame and compression of the gas in the throat section is transferred to the fuel by the liner. As a result, the liner must either have a very high thermal conductivity or a very high operating temperature. In addition to the large heat flux (>10 MW/sq m), the liners experience a very large thermal gradient, typically more than 500 C over 1 mm. The gradient produces thermally induced stresses and strains that cause low cycle fatigue (LCF). Typically, a liner will experience a strain differential in excess of 1% between the cooling channel and the hot wall. Each time the engine is fired, the liner undergoes an LCF cycle. The number of cycles can be as few as one for an expendable booster engine, to as many as several thousand for a reusable launch vehicle or reaction control system. Finally, the liners undergo creep and a form of mechanical degradation called thermal ratcheting that results in the bowing out of the cooling channel into the combustion chamber, and eventual failure of the liner. GRCop-84, a Cu-Cr-Nb alloy, is generally recognized as the best liner material available at the time of this reporting. The alloy consists of 14% Cr2Nb precipitates in a pure copper matrix. Through experimental work, it has been established that the Zr will not participate in the formation of Laves phase precipitates with Cr and Nb, but will instead react with Cu to form the desired Cu-Zr compounds. It is believed that significant improvements in the mechanical properties of GRCop-84 will be realized by adding Zr. The innovation is a Cu-Cr-Nb-Zr alloy covering the composition range of 0.8 to 8.1 weight percent Cr, 0.7 to 7.2 weight percent Nb, 0.1 to 1.5 weight percent Zr, and balance Cu. The alloy combines two known strengthening mechanisms - dispersion strengthening by Cr2Nb precipitates (GRCop-84), and precipitation strengthening by CuxZr (AMZIRC) - to produce a synergistic increase in the capabilities of the alloy with the goal of achieving properties greater than either of the methods could achieve alone. The anticipated advantages of the alloy are higher strength at temperatures up to 700 C, improved creep strength, and significantly higher LCF lives relative to GRCop-84. The thermal expansion, thermal conductivity, and processing of the alloy are anticipated to remain largely unchanged relative to GRCop-84.

Ellis, David L.↗
NASA NTRS2019

Primary Nanocrystalline Anhydrous Chondrule Mesostasis: Limited Evidence of Secondary Alteration in Most CR Chondrites

The chondrule regions generally regarded to be most susceptible to aqueous alteration are mesostasis and Fe-Ni metal nodules. In CMs, studies of mesostasis have successfully placed contraints into their asteroidal histories. Unlike CM mesostasis, only a few studies of CR mesostasis are currently available [e.g. 1-4]. Here we study the effects aqueous alteration can have on the texture, composition, and mineralogy of CR chondrule mesostasis from 9 Antarctic CR chondrites: EET 92062,5, EET 96259,13, GRA 95229,77, GRO 95577,61 LAP 02342,44, LAP 04516,4, LAP 04720,16 and MIL 07525,7 and MIL 090001,2, generously provided by the U.S. Antarctic Meteorite Collection. To our knowledge, this is the first detailed TEM and compositional study of differences between chondrule setting in CR mesostasis. Based on these data, we place constraints on the degree to which these CRs record aqueous alteration.

Abreu, N. M.↗
DOE OSTI2024

Mechanical Response of Cr-Coated Zircaloy-4 Cladding to Pellet-Cladding Interactions

Chromium-coated zircaloy is a promising accident tolerant fuel (ATF) cladding design which can help mitigate high temperature oxidation. The mechanical response of the cladding during and after loading may be altered by the Cr coating throughout anticipated operational and accident occurrences such as a pellet-cladding interaction (PCI). In this work, the mechanical behavior of Cr-coated and uncoated cold worked stress-relieved (CWSR) Zircaloy-4 (Zry-4) cladding to PCI loading conditions are studied. Stress relaxation tests are performed on CWSR Zry-4 cladding using full-tube axial tension and internal pressurization to investigate mechanical anisotropy and rate-limiting deformation mechanisms of the uncoated Zry-4. These results are compared to internal pressure testing results of similar cladding with physical vapor deposition (PVD) Cr-coating to reveal how the Cr-coating affects the cladding mechanical response. Findings are discussed in the context of ATF cladding performance during operation and storage.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

Materials Data on Cr(PO3)3 by Materials Project

Cr(PO3)3 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.96–2.12 Å. In the second Cr3+ site, Cr3+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra and an edgeedge with one CrO6 octahedra. There are a spread of Cr–O bond distances ranging from 1.95–2.18 Å. There are six inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–46°. There are a spread of P–O bond distances ranging from 1.50–1.62 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 27°. There are a spread of P–O bond distances ranging from 1.45–1.66 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of P–O bond distances ranging from 1.46–1.66 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 22–49°. There are a spread of P–O bond distances ranging from 1.50–1.63 Å. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 48–54°. There are a spread of P–O bond distances ranging from 1.51–1.58 Å. In the sixth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–53°. There are a spread of P–O bond distances ranging from 1.49–1.59 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr3+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr3+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr3+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to two Cr3+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the tenth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr3+ and one P5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fourteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr3+ and one P5+ atom. In the fifteenth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr3+ and one P5+ atom. In the seventeenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr3+ and one P5+ atom. In the eighteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(MoS2)2 by Materials Project

Cr(MoS2)2 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are four inequivalent Mo+2.50+ sites. In the first Mo+2.50+ site, Mo+2.50+ is bonded to six S2- atoms to form distorted MoS6 octahedra that share corners with six CrS6 octahedra, edges with six MoS6 octahedra, and a faceface with one CrS6 octahedra. The corner-sharing octahedra tilt angles range from 47–56°. There are a spread of Mo–S bond distances ranging from 2.37–2.61 Å. In the second Mo+2.50+ site, Mo+2.50+ is bonded to six S2- atoms to form distorted MoS6 octahedra that share corners with six CrS6 octahedra, edges with six MoS6 octahedra, and a faceface with one CrS6 octahedra. The corner-sharing octahedra tilt angles range from 48–57°. There are a spread of Mo–S bond distances ranging from 2.37–2.61 Å. In the third Mo+2.50+ site, Mo+2.50+ is bonded to six S2- atoms to form distorted MoS6 octahedra that share corners with six CrS6 octahedra, edges with six MoS6 octahedra, and a faceface with one CrS6 octahedra. The corner-sharing octahedra tilt angles range from 48–59°. There are a spread of Mo–S bond distances ranging from 2.38–2.64 Å. In the fourth Mo+2.50+ site, Mo+2.50+ is bonded to six S2- atoms to form distorted MoS6 octahedra that share corners with six CrS6 octahedra, edges with six MoS6 octahedra, and a faceface with one CrS6 octahedra. The corner-sharing octahedra tilt angles range from 48–58°. There are a spread of Mo–S bond distances ranging from 2.37–2.64 Å. There are two inequivalent Cr3+ sites. In the first Cr3+ site, Cr3+ is bonded to six S2- atoms to form CrS6 octahedra that share corners with twelve MoS6 octahedra, edges with two equivalent CrS6 octahedra, and faces with two MoS6 octahedra. The corner-sharing octahedra tilt angles range from 47–59°. There are a spread of Cr–S bond distances ranging from 2.45–2.51 Å. In the second Cr3+ site, Cr3+ is bonded to six S2- atoms to form CrS6 octahedra that share corners with twelve MoS6 octahedra, edges with two equivalent CrS6 octahedra, and faces with two MoS6 octahedra. The corner-sharing octahedra tilt angles range from 48–58°. There are a spread of Cr–S bond distances ranging from 2.45–2.53 Å. There are eight inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to three Mo+2.50+ and two Cr3+ atoms. In the second S2- site, S2- is bonded in a 5-coordinate geometry to three Mo+2.50+ and two Cr3+ atoms. In the third S2- site, S2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Cr3+ atom. In the fourth S2- site, S2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Cr3+ atom. In the fifth S2- site, S2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Cr3+ atom. In the sixth S2- site, S2- is bonded in a 4-coordinate geometry to three Mo+2.50+ and one Cr3+ atom. In the seventh S2- site, S2- is bonded in a 5-coordinate geometry to three Mo+2.50+ and two Cr3+ atoms. In the eighth S2- site, S2- is bonded in a 5-coordinate geometry to three Mo+2.50+ and two Cr3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(CO)6 by Materials Project

Cr(CO)6 is beta Np structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four Cr(CO)6 clusters. Cr3+ is bonded in an octahedral geometry to six C+1.50+ atoms. There is four shorter (1.92 Å) and two longer (1.93 Å) Cr–C bond length. There are four inequivalent C+1.50+ sites. In the first C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Cr3+ and one O2- atom. The C–O bond length is 1.16 Å. In the second C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Cr3+ and one O2- atom. The C–O bond length is 1.16 Å. In the third C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Cr3+ and one O2- atom. The C–O bond length is 1.16 Å. In the fourth C+1.50+ site, C+1.50+ is bonded in a distorted linear geometry to one Cr3+ and one O2- atom. The C–O bond length is 1.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+1.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+1.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+1.50+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C+1.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(CO)6 by Materials Project

Cr(CO)6 is beta Np structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four Cr(CO)6 clusters. Cr3+ is bonded in an octahedral geometry to six O2- atoms. There are one shorter (2.00 Å) and five longer (2.02 Å) Cr–O bond lengths. There are four inequivalent C+1.50+ sites. In the first C+1.50+ site, C+1.50+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.16 Å. In the second C+1.50+ site, C+1.50+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.16 Å. In the third C+1.50+ site, C+1.50+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.16 Å. In the fourth C+1.50+ site, C+1.50+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Cr3+ and one C+1.50+ atom. In the second O2- site, O2- is bonded in a linear geometry to one Cr3+ and one C+1.50+ atom. In the third O2- site, O2- is bonded in a linear geometry to one Cr3+ and one C+1.50+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to one Cr3+ and one C+1.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(PO4)2 by Materials Project

Cr(PO4)2 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of two Cr(PO4)2 sheets oriented in the (0, 0, 1) direction. Cr6+ is bonded to six O2- atoms to form distorted CrO6 octahedra that share corners with five PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.59–2.15 Å. 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 three equivalent CrO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 27–55°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and a cornercorner with one PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 31–48°. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr6+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr6+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one Cr6+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr6+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr6+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(PO3)5 by Materials Project

Cr(PO3)5 crystallizes in the monoclinic Pc space group. The structure is two-dimensional and consists of one Cr(PO3)5 sheet oriented in the (0, 1, 0) direction. Cr5+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.98–2.07 Å. There are five inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–43°. There is two shorter (1.50 Å) and two longer (1.61 Å) P–O bond length. In the third P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.60 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–48°. There is two shorter (1.51 Å) and two longer (1.62 Å) P–O bond length. In the fifth P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–43°. There is two shorter (1.50 Å) and two longer (1.61 Å) P–O bond length. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr5+ and one P5+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr5+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the seventh O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr5+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr5+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr5+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr5+ and one P5+ atom. In the fourteenth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the fifteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(PO3)5 by Materials Project

Cr(PO3)5 crystallizes in the monoclinic P2_1/m space group. The structure is two-dimensional and consists of one Cr(PO3)5 sheet oriented in the (0, 0, 1) direction. Cr5+ is bonded to six O2- atoms to form CrO6 octahedra that share corners with six PO4 tetrahedra. There are a spread of Cr–O bond distances ranging from 1.91–1.99 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedral tilt angles are 41°. There are a spread of P–O bond distances ranging from 1.47–1.64 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent CrO6 octahedra and corners with two PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–49°. There are a spread of P–O bond distances ranging from 1.51–1.60 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There is two shorter (1.51 Å) and two longer (1.61 Å) P–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr5+ and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cr5+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two P5+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent P5+ atoms. In the seventh O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cr5+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(GaS2)2 by Materials Project

Cr(GaS2)2 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one Cr(GaS2)2 sheet oriented in the (0, 0, 1) direction. Cr2+ is bonded to six S2- atoms to form CrS6 octahedra that share corners with six GaS4 tetrahedra and edges with six equivalent CrS6 octahedra. There are four shorter (2.47 Å) and two longer (2.49 Å) Cr–S bond lengths. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three equivalent CrS6 octahedra and corners with six equivalent GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are a spread of Ga–S bond distances ranging from 2.29–2.36 Å. In the second Ga3+ site, Ga3+ is bonded to four S2- atoms to form GaS4 tetrahedra that share corners with three equivalent CrS6 octahedra and corners with six equivalent GaS4 tetrahedra. The corner-sharing octahedra tilt angles range from 59–60°. There are a spread of Ga–S bond distances ranging from 2.29–2.36 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to three equivalent Cr2+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing SCr3Ga trigonal pyramids. In the second S2- site, S2- is bonded to three equivalent Cr2+ and one Ga3+ atom to form a mixture of distorted edge and corner-sharing SCr3Ga trigonal pyramids. In the third S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Ga3+ atoms. In the fourth S2- site, S2- is bonded in a trigonal non-coplanar geometry to three equivalent Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(NO2)2 by Materials Project

CrN2O5CrN2O3 crystallizes in the monoclinic Pm space group. The structure is one-dimensional and consists of one CrN2O3 ribbon oriented in the (0, 1, 0) direction and one CrN2O5 ribbon oriented in the (0, 1, 0) direction. In the CrN2O3 ribbon, Cr6+ is bonded in a tetrahedral geometry to one N1+ and three O2- atoms. The Cr–N bond length is 1.55 Å. There is one shorter (1.61 Å) and two longer (1.98 Å) Cr–O bond length. There are two inequivalent N1+ sites. In the first N1+ site, N1+ is bonded in a water-like geometry to two equivalent O2- atoms. Both N–O bond lengths are 1.28 Å. In the second N1+ site, N1+ is bonded in a single-bond geometry to one Cr6+ atom. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr6+ and one N1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom. In the CrN2O5 ribbon, Cr6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Cr–O bond distances ranging from 1.60–1.92 Å. There are two inequivalent N1+ sites. In the first N1+ site, N1+ is bonded in a single-bond geometry to one O2- atom. The N–O bond length is 1.22 Å. In the second N1+ site, N1+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.15 Å) and two longer (2.02 Å) N–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one Cr6+ and one N1+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr6+ and one N1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one Cr6+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one N1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(NO3)5 by Materials Project

Cr(NO3)5 is alpha Selenium structured and crystallizes in the trigonal P3_221 space group. The structure is zero-dimensional and consists of three Cr(NO3)5 clusters. Cr5+ is bonded in an octahedral geometry to six O2- atoms. There are a spread of Cr–O bond distances ranging from 2.04–2.07 Å. There are three inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.24 Å) and one longer (1.31 Å) N–O bond length. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.30 Å. In the third N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.21 Å) and two longer (1.31 Å) N–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the second O2- site, O2- is bonded in an L-shaped geometry to one Cr5+ and one N5+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr5+ and one N5+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr5+ and one N5+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one N5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cr(PO3)2 by Materials Project

Cr(PO3)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Cr2+ sites. In the first Cr2+ site, Cr2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cr–O bond distances ranging from 2.08–2.13 Å. In the second Cr2+ site, Cr2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cr–O bond distances ranging from 2.07–2.43 Å. There are four inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.63 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.50–1.61 Å. In the third P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.47–1.63 Å. In the fourth P5+ site, P5+ is bonded to four O2- atoms to form corner-sharing PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.49–1.62 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two Cr2+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to one Cr2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Cr2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to one P5+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the eighth O2- site, O2- is bonded in a bent 120 degrees geometry to two P5+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Cr2+ and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr2+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cr2+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Mechanical and chemical properties of PVD and cold spray Cr-coatings on Zircaloy-4

In this paper, accident-tolerant fuel (ATF) cladding materials aim to improve fuel reliability and safety during accident scenarios in water-cooled reactors. These ATF cladding should also perform comparable or better than the current zirconium alloy cladding under reactor normal operating conditions. Surface-modified Zircaloy-4 was produced by depositing a protective coating of chromium by two different coating techniques, Physical Vapor Deposition (PVD) and Cold Spray (CS). The coating thickness, structure, composition, and mechanical properties of the coated Zircaloy were assessed with advanced materials characterization techniques. Results showed a strengthening effect of the Cr-coating, along with ~83% higher hardness compared to that of the Zircaloy-4 substrate. Surface topography and surface chemistry of the Cr-coated Zircaloy-4 were assessed with contact profilometry, atomic force microscopy, contact angle goniometry, and X-ray photoelectron spectroscopy. Deposited Cr-coating significantly improved surface wettability compared to the substrate Zircaloy-4. The formation of surface oxides on the coatings by prolonged exposure to ambient air showed a further increase in the hydrophobic behavior. Surface parameters and surface chemistry after flow boiling critical heat flux tests, conducted at atmospheric pressure, evidenced a slight increase in surface roughness with notable changes in wettability associated with the formation of surface oxides.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Revealing the chemical environment of Cr, Fe, and Ni in high temperature-ultrafine precipitate strengthened steel subjected to low fluence neutron irradiation

High-temperature ultrafine-precipitate-strengthened (HT-UPS) steel has potential applications in advanced nuclear reactors as a structural material. However, little is currently known about its response to neutron irradiation. This research provides insight into the neutron irradiation-induced physicochemical changes of the major constituents in HT-UPS steels, including Fe, Cr, and Ni, using synchrotron X-ray absorption near edge structure (XANES) and diffraction. This study is the first known investigation using XANES to characterize HT-UPS steel to analyze the evolution of the atomic level chemistry. It was found that following irradiation, nucleation, ballistic dispersion, and/or coarsening of Cr 23 C 6 precipitates occurred at very low neutron irradiation fluences, from 0.003 displacements per atom (dpa) up to 0.3 dpa, at ~600°C, which were at least an order of magnitude lower than previous studies. Calculations of the angular momentum projections, partial density of states, and the XANES spectra confirmed the experimental findings of the Cr 23 C 6 precipitate evolution. In contrast, the local atomic structure around Fe and Ni atoms demonstrated irradiation resistance.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Advanced neutron absorber Ni-Cr-Mo-Gd alloys seawater corrosion mechanism and susceptibility study

Previous studies demonstrated the corrosion susceptibility of advanced neutron absorber (ANA) Ni-Cr-Mo-Gd in a seawater environment but remained inconclusive. In this paper, scanning electron microscopy was employed to identify the corrosion phase in Ni-Cr-Mo-Gd, and computational thermodynamic simulation was used to study phase corrosion potentials. Results showed that the Ni 5 Gd second phase, distributed along FCC grain boundaries in Ni-Cr-Mo-Gd, has lower corrosion potential than the substrate. Furthermore, heat treatment and alloy chemistry adjustment would not ameliorate the ANA corrosion susceptibility. Finally, isolating the Ni 5 Gd from the corrosion medium through advanced manufacturing is a viable way to improve the ANA corrosion resistance.

36 MATERIALS SCIENCE↗