Oxidation behavior of ytterbium silicide

Miyazaki, Toshihisa; Usami, Syo; Inoue, Ryo; Kogo, Yasuo; Arai, Yutaro

doi:10.1016/j.ceramint.2018.10.024

Cited by 18 publications

(10 citation statements)

References 15 publications

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“…Local thermal stresses were induced in the Si BC around cristobalite, thereby facilitating the propagation of cracks in the Si BC layer. A novel bond coat material is explored and some candidates have been evaluated, however, attractive candidates are not found so far 9–12 …”

Section: Introductionmentioning

confidence: 99%

“…A novel bond coat material is explored and some candidates have been evaluated, however, attractive candidates are not found so far. [9][10][11][12] After the heat exposure of the EBC system, the coefficient of thermal expansion (CTE) of silicate TC (~4-8 × 10 −6 /°C) was higher than those of the Si BC (~4 × 10 −6 /°C) and SiC/SiC substrates (~4-5 × 10 −6 /°C), thereby indicating that the thermal stresses were evolved in each layer. 2,13 It was assumed that the thermal compressive stress was primarily applied in the Si BC layer because the CTE for Si BC was lower than those of the TC and substrate.…”

Section: Introductionmentioning

confidence: 99%

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Anisotropic crack propagation behavior for the silicon‐bond coat layer in a multilayer coated system

Arai

Inoue

Kakisawa

2021

Int J Applied Ceramic Tech

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This study sought to examine the relationship between the degradation mechanism, thermal stress, and crack propagation behavior in environmental barrier coating (EBC) systems. An EBC system composed of a mullite topcoat (TC), Si‐bond coat (BC), and SiC substrate was prepared by atmospheric plasma spraying. Heat exposure tests were conducted to evaluate the microstructure of the EBC system at 1300°C for 1, 10, 50, and 100 h. The fracture resistance of the Si BC for the in‐plane (direction parallel to each layer, 0.4–0.6 MPnormalam) and through‐thickness directions (direction from the TC to substrate, 1.7–2.1 MPnormalam) differed because a thermal compressive stress was induced for the in‐plane direction owing to the mismatch of the thermal expansion coefficients for each layer, which acted as a barrier for crack propagation. However, cracks tended to propagate in the in‐plane direction because they were not affected by the in‐plane compressive stress. These results clearly showed that Si BC exhibited in‐plane anisotropy and crack propagation after heat exposure, which were the major sources of delamination of the EBC system.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Anisotropic crack propagation behavior for the silicon‐bond coat layer in a multilayer coated system

Arai

Inoue

Kakisawa

2021

Int J Applied Ceramic Tech

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“…Recently, some researchers have evaluated the degradation behavior of rare-earth silicides for their application as advanced bond coat materials [17][18][19][20]. They investigated the degradation behaviors of Yb3Si5 and Yb5Si3 at temperatures up to 1200 °C in air, steam, and mixed environments because their melting point is higher than that of Si [19,20]. The studies revealed that these silicides oxidize, and Yb2O3, Yb2SiO5, and Yb2Si2O7 form ultimately.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, rare-earth silicates and silicides are considered as potential candidates for environmental barrier coatings (EBCs) for aero-gas turbine engines [13][14][15][16][17][18][19][20]. EBCs are mainly composed of two layers of coating: a topcoat and a bond coat.…”

Section: Introductionmentioning

confidence: 99%

Improvement of the Oxidation Behavior of Yb-Gd-Si Ternary Alloys at Low Temperatures via Ti Addition

Arai

Morigayama

Aoki

et al. 2021

Preprint

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To improve the oxidation behavior of Yb-Gd-Si, 0.5 and 1 at% of Ti-containing Yb-Gd-Si (denoted as YGTS-0.5 and YGTS-1, respectively) were fabricated by arc melting. The oxidation behaviors of both YGTS specimens were evaluated by oxidation tests performed in a temperature range of 600–1200 °C for 1, 2, 4, and 8 h in air. Additionally, thermogravimetric analysis (TGA) was conducted at the abovementioned temperature range in air and steam. Oxidation tests at 1200 °C revealed no significant changes in the oxidation rate. Moreover, the oxidation tests revealed that Yb-Gd-Si and YGTS-0.5 became powdery after oxidation, whereas YGTS-1 maintained its form. Detailed microstructural observations indicated that the formation of TiO2 and other oxides in the Yb-Ti-O phase and oxide-containing Yb, Gd, Ti, and Si suppressed the formation of Yb2O3, which caused drastic oxidation at intermediate temperatures (600–900 °C). These results indicated that the addition of 1 at% of Ti to Yb-Gd-Si was effective in improving its oxidation behavior.

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“…Transition metal (TM) silicides are attractive advanced functional materials due to their excellent electronic properties, good thermoelectric properties, high temperature strength, excellent oxidation resistance, etc. [ 1–13 ] For example, the previous works have shown that tungsten silicides are regarded as fascinating renewed thermoelectric or energy materials. [ 14–17 ] Molybdenum (Mo) or niobium (Nb) silicides are attractive high‐temperature structural materials due to their high melting point, greater hardness, good thermodynamic stability, etc.…”

Section: Introductionmentioning

confidence: 99%

First‐principles investigation of structural, electronic, and optical properties of transition metal‐dopedC40 CrSi₂

Pan

2020

Int J of Quantum Chemistry

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Although CrSi 2 silicide is an attractive advanced functional material, the improvement of electronic and optical properties is still a challenge for its applications. Here, we apply the first-principles calculations to investigate the influence of transition metals (TMs) on the electronic and optical properties of C40 CrSi 2 silicide. Five possible TMs, Ti, V, Pd, Ag, and Pt, are considered in detail. The calculated results show that the additive metals Ti, V, Pd, and Pt are thermodynamically stable in C40 CrSi 2 because the calculated impurity formation energy of TM-doped C40 CrSi 2 is lower than zero. In particular, the V dopant is more thermodynamically stable than that of the other TMs. The calculated electronic structure shows that the band gap of C40 CrSi 2 is 0.391 eV, which is in good agreement with the other results. In particular, the additive TMs improve the electronic properties of C40 CrSi 2 due to the role of the d-state of TMs. Naturally, the additive TMs result in band migration (Cr-3d state and Si-3p state) from the valence band to the conduction band. Interestingly, the additive TMs lead to a red shift for optical adsorption of C40 CrSi 2 silicide. K E Y W O R D S alloying, C40 CrSi 2 , electronic properties, first-principles calculations, optical properties 1 | INTRODUCTION Transition metal (TM) silicides are attractive advanced functional materials due to their excellent electronic properties, good thermoelectric properties, high temperature strength, excellent oxidation resistance, etc. [1-13] For example, the previous works have shown that tungsten silicides are regarded as fascinating renewed thermoelectric or energy materials. [14-17] Molybdenum (Mo) or niobium (Nb) silicides are attractive hightemperature structural materials due to their high melting point, greater hardness, good thermodynamic stability, etc. [18-24] Recently, chromium silicide (CrSi 2) has received great attention as thermoelectric and storage energy materials. [25-27] It is well known that the overall performances of TM silicides or compounds are markedly influenced by their structural feature. [28-32] Regarding thermoelectric materials, Zhang and Wang have found that the higher anisotropy of electrical conductivity results in the thermoelectric properties of the hexagonal CrSi 2 , [33] while the narrow band gap of C40 CrSi 2 is 0.3 to 0.35 eV. Oader and Venkat prepared a CrSi 2 thermoelectric thin film using the magnetron sputtering method. [34] Furthermore, Mikami and Kinemuchi studied the microstructure and thermoelectric performance of WSi 2 on CrSi 2 silicide. [35] They found that the additive WSi 2 reduces the grain size of CrSi 2 and improves the ZT value of CrSi 2-based material. Regarding promising storage energy material, Menda and Ozdemir studied the capacitance voltage temperature (C-V-T) and current voltage temperature (I-V-T) of p-CrSi 2 /Si using the physical vapor deposition (CAPVD) method, [36] while the measured building voltage was about 0.7 V. Bhamu and Ahuja theoretically studied the electronic st...

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Oxidation behavior of ytterbium silicide

Cited by 18 publications

References 15 publications

Anisotropic crack propagation behavior for the silicon‐bond coat layer in a multilayer coated system

Anisotropic crack propagation behavior for the silicon‐bond coat layer in a multilayer coated system

Improvement of the Oxidation Behavior of Yb-Gd-Si Ternary Alloys at Low Temperatures via Ti Addition

First‐principles investigation of structural, electronic, and optical properties of transition metal‐dopedC40 CrSi₂

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Oxidation behavior of ytterbium silicide

Cited by 18 publications

References 15 publications

Anisotropic crack propagation behavior for the silicon‐bond coat layer in a multilayer coated system

Anisotropic crack propagation behavior for the silicon‐bond coat layer in a multilayer coated system

Improvement of the Oxidation Behavior of Yb-Gd-Si&nbsp;Ternary Alloys at Low Temperatures via Ti Addition

First‐principles investigation of structural, electronic, and optical properties of transition metal‐dopedC40 CrSi2

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Product

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Improvement of the Oxidation Behavior of Yb-Gd-Si Ternary Alloys at Low Temperatures via Ti Addition

First‐principles investigation of structural, electronic, and optical properties of transition metal‐dopedC40 CrSi₂