JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 106
·期 4
·2476-2490
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IF 4.186
Chenkai Qu,Lin Chen,Tao Su,Dongbo Li,Yuan Yang,Jing Feng
Ferroelastic YTaO 4 is a promising material for thermal barrier coatings (TBCs), and its thermal and mechanical properties can be further optimized by various methods. In this study, a ferroelastic middle-entropy ceramic Y 0.5 Gd 0.5 Ta 0.5 Nb 0.5 O 4 was synthesized by solid-phase sintering, and its microstructures and thermophysical properties were key points. We determined the contributions of phonons and photons to total thermal conductivity, and a low thermal conductivity was obtained by inhibiting high-temperature thermal radiation. The thermal expansion coefficients were improved by introducing of Nb atom into the lattice of the prepared middle-entropy ceramic, which meets the requirements of TBCs. The improved wear resistance originated from relatively high Young's modulus and the hardness of Y 0.5 Gd 0.5 Ta 0.5 Nb 0.5 O 4 , and it would contribute to the service performance of the corresponding coatings. This work motivates the engineering applications of ferroelastic RETaO 4 and RENbO 4 (RE is rare-earth element) as high-temperature TBCs.
研究领域:
材料科学
·
热力学工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Xinyu Ping,Bin Meng,Xiaohua Yu,Qingqing Yang,Zhiyuan Ma,Xiaoyu Pan
A medium-entropy fluorite-structured ceramic of (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25 )O 2−δ was prepared using a solid state reaction method combined with conventional sintering at 1600 ° C for 10 h. This ceramic has uniform elemental distribution without impurity and segregation. The annealing experiment results show a reversible transformation between single phase and double phases in (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25 )O 2−δ in 800–1600 °C. The reversible phase transformation does not display any obvious influence on the thermal expansion of this sample. The thermal expansion coefficient of (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25 )O 2−δ is 12.4 × 10 −6 K −1 in 100–1500 °C, higher than that of 8 wt% yttria-stabilized zirconia (8 YSZ). Furthermore, (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25 )O 2−δ possesses a lower thermal conductivity (1.51 W m −1 K −1 at 900 ° C) and higher oxygen barrier property compared with 8 YSZ at high temperature. The Vickers' hardness, Young's modulus and fracture toughness of (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25 )O 2−δ are 10.0 GPa, 193.9 GPa and 1.93 MPa m 1/2 , respectively. These results demonstrate that (Y 0·25 Zr 0.25 Hf 0.25 Ce 0.25 )O 2−δ can be used as a promising candidate ceramic of thermal barrier coatings.
研究领域:
材料科学
·
热物理性质
·
陶瓷材料
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2025
·Vol. 32
·期 6
·1441-1450
·
IF 7.2
Chen Xunlei,Chen Lin,Tian Jiang,Xu Cheng,Liao Jiaxin,Li Tianyu,Wang Jiankun,Feng Jing
Thermal and mechanical properties of yttrium tantalate (YTaO 4 ), a top coat ceramic of thermal barrier coatings (TBCs) for aeroengines, are enhanced by synthesizing Y 1− x Ta 1− x M 2 x O 4 (M = Ti, Zr, Hf; x = 0.06, 0.12, 0.18, 0.24) medium-entropy ceramics (MECs) using a two-step sintering method. In addition, the thermal conductivity, thermal expansion coefficients (TECs), and fracture toughness of MECs were investigated. An X-ray diffraction study revealed that the Y 1− x Ta 1− x M 2 x O 4 MECs were monoclinic, and the Ti, Zr, and Hf doping elements replaced Y and Ta. The variations in atomic weights and ionic radii led to disturbed atomic arrangements and severe lattice distortions, resulting in improving the phonon scattering and reduced thermal conductivity, with Y 1− x Ta 1− x M 2 x O 4 MECs ( x = 0.24) exhibiting the lowest thermal conductivity of 1.23 W·m −1 ·K −1 at 900°C. The introduction of MO 2 increased the configurational entropy and weakened the ionic bonding energy, obtaining high TECs (10.4 × 10 −6 K −1 at 1400°C). The reduction in the monoclinic angle β lowered the ferroelastic domain inversion energy barrier. Moreover, microcracks and crack extension toughening endowed Y 1− x Ta 1− x M 2 x O 4 MECs ( x = 0.24) with the highest fracture toughness of (4.1 ± 0.5) MPa·m 1/2 . The simultaneous improvement of the thermal and mechanical properties of the MO 2 (M = Ti, Zr, Hf) co-doped YTaO 4 MECs can be extended to other materials.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Siyue Wei,Xue Chen,Guangzhi Dong,Laijun Liu,Qi Zhang,Biaolin Peng
Ferroelectric ceramic with a large electrocaloric ( EC ) effect at a very low electric field is very attractive in the next solid state refrigeration technology. In this work, two Pb(Sc 0.25 In 0.25 Nb 0.25 Ta 0.25 )O 3 (PSINT) medium-entropy ceramics were successfully synthesized by a spark plasma sintering (SPS) technology, including one-step-SPS processed and two-step-SPS processed samples. A large EC effect (△ T ∼ 0.85 K) with a high EC strength (△ T /△ E ∼ 0.021 K cm/kV) around room temperature are obtained at a very low electric field (∼40 kV/cm) in the two-step-SPS processed sample. Moreover, the working temperature range is very broad (∼120 K), which can be responsible for the high relaxation degree of the dielectric peak. It can be believed that the PSINT medium-entropy ceramics can be promising candidates for application in the next-generation EC cooling devices.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
Nature Communications
·
2024
·Vol. 15
·期 1
·1-11
·
IF 14.7
Chen Chao,Ma Yinglin,Yao Kunda,Ji Qingmin,Liu Wei
Chiral metal surfaces provide an environment for enantioselective adsorption in various processes such as asymmetric catalysis, chiral recognition, and separation. However, they often suffer from limitations such as reduced enantioselectivity caused by kink coalescence and atomic roughness. Here, we present an approach using medium-entropy ceramic (MEC), specifically (CrMoTa)Si 2 with a C40 hexagonal crystal structure, which overcomes the trade-off between thermal stability and enantioselectivity. Experimental confirmation is provided by employing quartz crystal microbalance (QCM), where the electrode is coated with MEC films using non-reactive magnetron sputtering technology. The chiral nature is verified through transmission electron microscopy and circular dichroism. Density-functional theory (DFT) calculations show that the stability of MEC films is significantly higher than that of high-index Cu surfaces. Through a combination of high-throughput DFT calculations and theoretical modeling, we demonstrate the high enantioselectivity (42% e.e.) of the chiral MEC for serine, a prototype molecule for studying enantioselective adsorption. The QCM results show that the adsorption amount of L-serine is 1.58 times higher than that of D-serine within a concentration range of 0-60 mM. These findings demonstrate the potential application of MECs in chiral recognition.
研究领域:
材料科学
·
表面化学
·
催化
·
手性
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）