Hot-corrosion of refractory high-entropy ceramic matrix composites synthesized by alloy melt-infiltration

Arai, Yutaro; Saito, Mitsuko; Samizo, Akane; Inoue, Ryo; Nishio, K.; Kogo, Yasuo

doi:10.1016/j.ceramint.2021.08.055

Cited by 16 publications

(11 citation statements)

References 45 publications

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“…Unfortunately, the weight gain and oxidation rate of these silicides depend on the oxides formed on their surfaces, and it is difficult to extract the effect of the mixed entropy on the oxidation behavior. As discussed previously [18], the formation of complex oxides containing Yb-Gd-Si-O (and Yb-Gd-Ti-Si-O) acts as a barrier for oxygen diffusion into the unoxidized area, and similar mechanisms have been reported in studies on the oxidation mechanism of mid-and high-entropy materials [20][21][22].…”

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confidence: 53%

Degradation of Yb–Gd–Ti-Si middle entropy silicides in oxidizing atmosphere

Arai¹,

Inoüe²

2022

Mater. Res. Express

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Using arc melting, a novel rare-earth silicide, middle entropy Yb-Gd-Ti-Si, was fabricated for high-temperature material applications. The oxidation behavior of the Yb-Gd-Ti-Si was evaluated through oxidation tests conducted at 1200 °C for 1, 2, 4, and 8 h in air. The oxidation rate at 1200 °C was almost the same, regardless of the addition of Ti. The oxidation rate of Yb-Gd-Ti-Si at lower temperatures (600 °C to 900 °C) was lower than that of Yb-Gd-Si. In addition, detailed microstructural observations indicate that the formation of TiO2 and other oxides in the Yb-Ti-O (Yb-Ti-Si-O) phase suppresses the formation of Yb2O3, causing a drastic oxidation at intermediate temperatures (600 °C to 900 °C). These results indicate that the addition of Ti to Yb-Gd-Si is effective at preventing the preferential oxidation of the grain boundaries at 600 °C to 900 °C, which is commonly observed in metal silicides

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confidence: 53%

Degradation of Yb–Gd–Ti-Si middle entropy silicides in oxidizing atmosphere

Arai¹,

Inoüe²

2022

Mater. Res. Express

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“…This is because the melting temperature of oxides formed on C/RHECs‐TZ is likely higher than those formed on C/RHECs‐TZM. Focusing on a solid phase ((Zr x Hf 1− x )O 2 ) and a liquid phase ((Zr y Hf 6− y )(Ta x Nb 2− x )O 17 ) at approximately 2000°C, which are formed commonly for these composites, XRD patterns for (Zr x Hf 1− x )O 2 are remarkable for C/RHECs‐TZ, 39 whereas patterns for (Zr y Hf 6− y )(Ta x Nb 2− x )O 17 are remarkable for C/RHECs‐TZM. The intensity ratio of (11‐1) peak for (Zr x Hf 1− x )O 2 to (811) peak for (Zr y Hf 6− y )(Ta x Nb 2− x )O 17 for C/RHECs‐TZ after oxidation under the same conditions is approximately 1, and for C/RHECs‐TZM, it is approximately .11.…”

Section: Resultsmentioning

confidence: 99%

“…The detailed fabrication methods for preforms had been reported elsewhere. 39 In the present study, Ti−60Zr−2.5Mo and Ti−50Zr−30Mo (at.%) alloys were selected as MI alloys as mentioned in Section 2. As raw materials, chunks of Ti and Zr (purity: 98−99%, Kojundo Chemical Laboratory Co., Ltd.), and Mo wires with a diameter of φ approximately 1 mm and a length of approximately 10 mm (purity: ∼99%, Nilaco Corporation) were selected.…”

Section: Methodsmentioning

confidence: 99%

“…The sample was exposed to high‐enthalpy flow for 5 min and the surface temperature during the arc‐wind tunnel was measured using a two‐color radiation thermometer (IR‐AQ, CHINO Corporation). The emissivity was set to one to ensure the minimum temperature during the arc‐wind tunnel test, as described in a previous report 39 . After exposure, the observation of microstructure, evaluation of crystal structure, and elemental analyses were conducted using SEM–EDS and XRD.…”

Section: Methodsmentioning

confidence: 99%

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Material design using calculation phase diagram for refractory high‐entropy ceramic matrix composites

Arai,

Saito,

Samizo

et al. 2024

Int J Applied Ceramic Tech

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To achieve Si‐free refractory ceramic matrix composites exposed to an oxidizing atmosphere at approximately 2000°C, a Ti–Zr–Mo ternary alloy melt‐infiltration (MI) method was developed for the production of carbon fiber‐reinforced refractory high‐entropy ceramic matrix composites (C/RHECs), with high‐entropy carbides serving as the matrix. This approach was designed using calculation phase diagrams (CALPHADs) and the calculation of thermodynamic parameters. The combination of CALPHAD and the calculation of alloy and carbon reactivity enabled the prediction of reaction and infiltration behavior into a preform comprising carbon fiber, carbon black, and transition metal carbide powders. Furthermore, C/RHECs featuring a (Ti, Zr, Hf, Nb, Ta, Nb, Mo)C matrix were experimentally fabricated through the Ti–Zr–Mo alloy MI method in accordance with the design. The arc‐wind tunnel tests on the C/RHECs conducted at approximately 2000°C revealed surfaces covered with complex oxides. The apparent oxidation rate of the C/RHECs was similar to that of Si‐containing ceramics and composites. These results indicate that complex oxides act as a barrier to oxygen diffusion toward unoxidized regions, making Si no longer essential for protecting materials from oxidation above 2000°C.

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“…Refractories are the class of ceramic materials that are suited for high temperatures, usually above 1100 • C, and are mostly made from naturally occurring high melting point oxides of SiO 2 , Al 2 O 3 , MgO, Cr 2 O 3 , ZrO, and they usually include aluminosilicate, dolomite, magnesia, silica, chrome, chrome-magnesite, carbon, etc. (Arai et al 2021, Brochen et al 2022. Refractory materials are materials that are capable of withstanding high temperatures, both physically and chemically.…”

Section: Introductionmentioning

confidence: 99%

Production and optimization of the refractory properties of blended Nigerian clay for high-temperature application; a non-stochastic optimization approach

Samuel

Adamu

Abutu

et al. 2023

Funct. Compos. Struct.

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High-performance materials, systems, and processes have necessitated the exploration of very high-temperature environments. Materials, particularly ceramics, which can withstand these high temperatures, have been extensively studied, even though enough emphasis has not been given to clays sourced locally in Nigeria, where there is an abundance. Also, stochastic optimization techniques has been employed to improve on system or carry out experimentation with minimal spend of resources and very high accuracy. This work extensively explored the refractory properties of blends developed from locally sourced clays (Mayo Ndaga and kachalla Sembe and Kona). The Taguchi optimization technique was employed to determine the effect of various quantities of the clays on the loss on ignition (LOI), refractoriness (RF), and firing shrinkage (FS) of the blends. It was discovered that the optimum (lowest) loss on ignition, highest refractoriness, and lowest firing shrinkage were 11%, 1333°C, and 0.48%, respectively. Analysis of variance also proved the significance of Mayo Ndaga on the refractoriness and firing shrinkage of the blends, with P-values of 0.038 and 0.000 at a 95% confidence level.

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Hot-corrosion of refractory high-entropy ceramic matrix composites synthesized by alloy melt-infiltration

Cited by 16 publications

References 45 publications

Degradation of Yb–Gd–Ti-Si middle entropy silicides in oxidizing atmosphere

Degradation of Yb–Gd–Ti-Si middle entropy silicides in oxidizing atmosphere

Material design using calculation phase diagram for refractory high‐entropy ceramic matrix composites

Production and optimization of the refractory properties of blended Nigerian clay for high-temperature application; a non-stochastic optimization approach

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