Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca2
 RE
 8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2

Crum, Jarrod V.; Chong, Saehwa; Peterson, James M.; Riley, Brian J.

doi:10.1107/s2056989019008442

Cited by 21 publications

(9 citation statements)

References 25 publications

(21 reference statements)

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“…After being corroded at 1250 for 1 h, ℃ MOCVD YSZ coating possessed a 5 μm-thick reaction layer while YSZ pellet infiltrated by CMAS for 4 h has a reaction layer with a depth of 50 μm. [65,66] are identified. However, XRD patterns of these three phases cannot match any of the unknown peaks in Fig.…”

Section: Mechanical Properties Of (Eumentioning

confidence: 99%

Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

et al. 2021

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Y2O3 is regarded as one of the potential environmental barrier coating (EBC) materials for Al2O3f/Al2O3 ceramic matrix composites owing to its high melting point and close thermal expansion coefficient to Al2O3. However, the relatively high thermal conductivity and unsatisfactory calcium-magnesium-aluminosilicate (CMAS) resistance are the main obstacles for the practical application of Y2O3. In order to reduce the thermal conductivity and increase the CMAS resistance, four cubic bixbyite structured high-entropy oxides RE2O3, including (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3, (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3, (Sm0.2Eu0.2Er0.2Y0.2Yb0.2)2O3, and (Sm0.2Eu0.2Lu0.2Y0.2Yb0.2)2O3 were designed and synthesized, among which (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 bulks were prepared by spark plasma sintering (SPS) to investigate their mechanical and thermal properties as well as CMAS resistance. The mechanical properties of (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 are close to those of Y2O3 but become more brittle than Y2O3. The thermal conductivities of (Eu0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 and (Sm0.2Er0.2Lu0.2Y0.2Yb0.2)2O3 (5.1 and 4.6 W·m−1·K−1) are only 23.8% and 21.5% respectively of that of Y2O3 (21.4 W·m−1·K−1), while their thermal expansion coefficients are close to those of Y2O3 and Al2O3. Most importantly, HE RE2O3 ceramics exhibit good CMAS resistance. After being attacked by CMAS at 1350 °C for 4 h, the HE RE2O3 ceramics maintain their original morphologies without forming pores or cracks, making them promising as EBC materials for Al2O3f/Al2O3 composites.

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Section: Mechanical Properties Of (Eumentioning

confidence: 99%

Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

et al. 2021

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“…Oxygen stoichiometric Ca‐RE oxyapatites, that is, Ca 2 RE 8 (SiO 4 ) 6 O 2 , have been reported for all RE, with the possible exceptions of Ho and Tm 38,39 . These oxyapatites are similar to the natural mineral britholite; when the RE is mostly yttrium, this is britholite‐Y (formerly abukumalite), (Y,Ca) 5 (SiO 4 ) 3 OH, or when it is mostly cerium is britholite‐Ce (formerly lessingite, beckelite), (Ce,Ca) 5 (SiO 4 ) 3 OH 40 .…”

Section: Discussionmentioning

confidence: 96%

Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Chen

Marcial

Ahmadzadeh

et al. 2020

Int J of Appl Glass Sci

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Alumino‐borosilicate glass‐ceramics (GCs) containing alkali (Na), alkaline earth (Ca), rare earth (RE) (one of La … Lu, Y), and transition metals (Zr and Mo) were formulated to test the effects of composition and RE cation size on the crystallization of simulated nuclear waste GCs. Eight‐oxide glasses were formulated in the peraluminous ([Na2Oexcess]=[Na2O]‐[Al2O3]‐[ZrO2]<0) region with 10 mol.% RE2O3 and 15 mol.% B2O3. Glasses were melted and quenched, reheated, and slow‐cooled to promote crystallization, and then characterized using quantitative X‐ray diffraction and electron probe microanalysis. Transition metal phases [powellite (Ca,Na,RE)MoO4 and zirconia (Zr,RE)O2 or zircon (Zr,RE)SiO4] always formed, while borosilicate (RE3BSi2O10) or silicate [oxyapatite (RE,Ca,Na)10Si6O26 or keiviite (RE2Si2O7)] plus borate (REBO3) phases also formed, depending on the size of the RE cation and hence its preferred coordination number. All crystalline phases were found to contain RE elements, and often phases incorporated other cations (Zr, Ca, B) which were not nominally part of their pure stoichiometry. These results suggested that the glass formulation and RE size strongly influenced the RE environment in the glass and hence the crystal phases formed. The formation of RE borosilicate, versus separate RE borate and RE silicate phases, also suggested original differences in the glass structure.

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“…However, to the best author´s knowledge, no diffraction file is available for the identification of this phase. Nevertheless, the main peaks located in 30.07 and 31.77° corresponding to the (112) and (211) planes of ApGd and ApLa, respectively [31] [32] (Fig. 4b, e) were taken as a reference for its classification as a La-Gd-apatite, provided that, according to the literature, RE-apatites show peaks that shifts to lower angles with increasing RE cation sizes [31] [32].…”

Section: Vas-lgzo Interactionsmentioning

confidence: 99%

Reaction Products from High Temperature Treatments of (LaxGd1−x)2Zr2O7 System and Volcanic Ash Powder Mixtures

Guijosa-García

Rivera-Gil

Ramana

et al. 2022

JOM

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Rare-earth zirconate (REZ) pyrochlores, specifically (La,Gd)2Zr2O7 are promising alternatives to substitute 7YSZ in thermal barrier coatings (TBC) due to their increased phase stability and resistance to calcium-magnesium-aluminosilicates (CMAS)-based damage at high temperatures. This work analyses the reaction products of isothermal treatments at 1250 °C of (LaxGd1-x)2Zr2O7 powder mixtures in reaction with natural volcanic ashes (VAs) with different chemical compositions (Popocatepetl, Colima, and Eyjafjallajökull). The chemical composition in the (LaxGd1-x)2Zr2O7 system showed a strong influence on the formation of reprecipitation products (Zr,Gd,La oxides), reactive crystallization products (La-Gd apatites, lanthanum silicates, zirconolite, and garnets), and intrinsic crystallization products (hematite-like structures). The formation of garnets, which enhance the mitigation effect against molten VAs/Si-deposits damage, was observed more promptly on (La0.5Gd0.5)2ZrO7 promoted by high contents of Fe, Ca, Ti, and Mg on VAs. Thus, the (La0.5Gd0.5)2ZrO7 system stands as a possible candidate to overcome today's threats for the integrity of current TBCs.

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Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca₂ RE ₈(SiO₄)₆O₂ (RE = La, Nd, Sm, Eu, or Yb) and NaLa₉(SiO₄)₆O₂

Cited by 21 publications

References 25 publications

Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Reaction Products from High Temperature Treatments of (LaxGd1−x)2Zr2O7 System and Volcanic Ash Powder Mixtures

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Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca2 RE 8(SiO4)6O2 (RE = La, Nd, Sm, Eu, or Yb) and NaLa9(SiO4)6O2

Cited by 21 publications

References 25 publications

Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

Preparation and properties of CMAS resistant bixbyite structured high-entropy oxides RE2O3 (RE = Sm, Eu, Er, Lu, Y, and Yb): Promising environmental barrier coating materials for Al2O3f/Al2O3 composites

Partitioning of rare earths in multiphase nuclear waste glass‐ceramics

Reaction Products from High Temperature Treatments of (LaxGd1−x)2Zr2O7 System and Volcanic Ash Powder Mixtures

Contact Info

Product

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Syntheses, crystal structures, and comparisons of rare-earth oxyapatites Ca₂ RE ₈(SiO₄)₆O₂ (RE = La, Nd, Sm, Eu, or Yb) and NaLa₉(SiO₄)₆O₂