Effect of CeO2 on the viscosity and structure of high-temperature melt of the CaO-SiO2(-Al2O3)-CeO2 system

Guo, Wentao; Wang, Zhi; Zhao, Zhiwei; An, Zhuoqing; Wang, Wenfeng

doi:10.1016/j.jnoncrysol.2020.120085

Cited by 17 publications

(4 citation statements)

References 43 publications

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“…The observable viscosity reduction through the addition of Ce 2 O 3 , however, contradicts the CFS theory, since the assumed presence of significant amounts of Ce 4+ in the CMAS melt (Figure 4) should lead to higher viscosities (CFS Ce4+ = 0.79 Å −2 ; CFS Ce3+ = 0.53 Å −2 ). This observation for Ce‐modified silicate melts corresponds with studies from Guo et al 36 . and Müller et al., 26 suggesting that the pure presence of multiple valence states can lead to lower viscosities.…”

Section: Discussionsupporting

confidence: 88%

“…35 The observable viscosity reduction through the addition F I G U R E 3 (A1, A2, and A3) Arrhenian viscosity plots for the pure S4 CMAS melt (dashed line) and the Gd of Ce 2 O 3 , however, contradicts the CFS theory, since the assumed presence of significant amounts of Ce 4+ in the CMAS melt (Figure 4) should lead to higher viscosities (CFS Ce4+ = 0.79 Å −2 ; CFS Ce3+ = 0.53 Å −2 ). This observation for Ce-modified silicate melts corresponds with studies from Guo et al 36 and Müller et al, 26 suggesting that the pure presence of multiple valence states can lead to lower viscosities. CMAS samples, doped with varying amounts of Gd 2 O 3 , Y 2 O 3 , and ZrO 2 compare very well with previous studies of YSZ and GZO modified CMAS melts with the same CMAS composition.…”

Section: Discussionsupporting

confidence: 88%

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Calcium–magnesium–aluminum‐silicate melt viscosities influenced by lanthanides, yttrium, and zirconium

Müller,

Dingwell

2024

J Am Ceram Soc.

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Lanthanides (Ln2O3) and elements like Zr and Y find application in the highest temperature‐resistant thermal and/or environmental barrier coatings. Such coatings are routinely exposed to silicate particles (e.g., sand, dust, volcanic ash), leading to chemical reactions that degrade the coating. The dissolution of 13.5 wt.% Ln2O3 into a calcium–magnesium–aluminum‐silicate (CMAS) melt leads to a viscosity reduction for the light lanthanides, while viscosity increases toward heavier lanthanides. For Gd, Y, and Zr, various amounts up to 13.5 wt.% (Gd2O3, Y2O3, ZrO2) were added to the CMAS melt, showing a tendency of increased viscosity for low concentrations (2.5‐3 wt.%) and a decreasing viscosity for higher values of the added component.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionsupporting

confidence: 88%

Calcium–magnesium–aluminum‐silicate melt viscosities influenced by lanthanides, yttrium, and zirconium

Müller,

Dingwell

2024

J Am Ceram Soc.

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“…After clarifying the interaction behavior and product formation mechanisms, the spreading areas and viscosity changes of the molten mixture of CMAS +CeO 2 could be explained (Figure 2). In silicate melts, the viscosity is determined mainly by Ca/Si, and the higher the Ca/Si, the lower the viscosity (inversely proportional) [47,48]. During the interaction of CeO 2 and CMAS, with the increase of the CeO 2 content and the duration time, more apatite is produced, which consumes a large amount of Ca in the CMAS melt.…”

Section: Effects Of the Ceo 2 Content And Duration Time On The Crysta...mentioning

confidence: 99%

CeO2 Protective Material against CMAS Attack for Thermal–Environmental Barrier Coating Applications

Guo

Wang

Liu³

et al. 2023

Coatings

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Calcium–magnesium–alumina–silicate (CMAS) attack is a crucial issue for thermal–environmental barrier coatings (T/EBCs) with the ever-increasing operating temperature of turbine engines. In this study, CeO2 has been demonstrated as a promising protective material for T/EBCs against CMAS attack. At 1300 °C, CeO2 powder kept excellent phase and structural stability in molten CMAS; there were some CMAS constituents dissolved into the CeO2 lattice to form a solid solution. With higher CeO2 contents and longer duration time, more CeO2 solid solution particles were formed, which acted as the nucleating agent for CMAS crystallization. As a result, apatite, anorthite and wollastonite crystalline products were easily generated. At 1300 °C for 10 h, CeO2 pellets covered with CMAS powder had limited degradation, which was attributed to the rapid crystallization of molten CMAS due to the excellent nucleating agent effect of the precipitated CeO2 solid solution.

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“…A Ce 3 + ion has the radius of 1.01 Å, which is larger than the radius of a Ca 2 + ion (1.0 Å) and Mg 2 + ion (0.69 Å). 10,13,23) The cationic field strengths were calculated and listed in Table 2. As can be seen from the table, Ca 2 + ion had the smallest cationic field strength in the current system.…”

Section: Theoretical Analysis On Structurementioning

confidence: 99%

Effect of Ce2O3 on the Melt Structure and Properties of CaO–Al2O3-based Slag

Zheng

Liu

2022

ISIJ Int.

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The low-reactive tundish flux is urgently required for the smelting of rare-earth steels. The effect of Ce 2 O 3 content on the properties (melting point and viscosity) and structure of CaO-Al 2 O 3 -Ce 2 O 3 -MgO-SiO 2 slag were analyzed in the present investigation. The research results indicated that the polymerized Q Al 4 and Q Al 3 units were modified to Q Al 2 units in aluminate, and the depolymerization of SiO 4 -tetrahedrons from Q Si 1 to Q Si 0 units with Ce 2 O 3 addition increasing from 5 wt% to 20 wt%. In addition, when the Ce 2 O 3 addition increased from 15 wt% to 20 wt%, the increasing area fraction in AlO 6 -octahedral units further led to a decrease in the degree of polymerization (DOP) in the melts. When the Ce 2 O 3 addition increased from 5 wt% to 20 wt%, the melting temperature decreased from 1 320°C to 1 301°C. Additionally, the softening temperature and the fluidity temperature also decreased 20°C and 24°C, respectively. The viscosity decreased as the Ce 2 O 3 addition increased from 5 wt% to 20 wt%, which was attributed to the decreased DOP and the increased superheat. A reasonable content for Ce 2 O 3 should not be excess 10 wt% in the current slag.

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Effect of CeO2 on the viscosity and structure of high-temperature melt of the CaO-SiO2(-Al2O3)-CeO2 system

Cited by 17 publications

References 43 publications

Calcium–magnesium–aluminum‐silicate melt viscosities influenced by lanthanides, yttrium, and zirconium

Calcium–magnesium–aluminum‐silicate melt viscosities influenced by lanthanides, yttrium, and zirconium

CeO2 Protective Material against CMAS Attack for Thermal–Environmental Barrier Coating Applications

Effect of Ce<sub>2</sub>O<sub>3</sub> on the Melt Structure and Properties of CaO–Al<sub>2</sub>O<sub>3</sub>-based Slag

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