JOURNAL OF MATERIALS SCIENCE
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2022
·Vol. 57
·期 37
·17563-17576
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IF 4.682
He Junjie,He Guo,Wang Panpan,Xu Lurun,Liu Jing,Tao Jingchao
In this work, new high-entropy RE 2 (Ce 0.2 Zr 0.2 Hf 0.2 Sn 0.2 Ti 0.2 ) 2 O 7 (RE 2 HE 2 O 7 , RE = La, Nd, Sm, Eu, Gd, Dy) ceramics were successfully prepared. RE 2 HE 2 O 7 ceramics exhibited a pyrochlore–fluorite dual-phase structure. For Sm 2 HE 2 O 7 ceramic, Ce 4+ with larger ionic radius was enriched in the fluorite phase, Sn 4+ and Ti 4+ with smaller ionic radii were enriched in the pyrochlore phase, while Zr 4+ and Hf 4+ with medium ionic radii existed in both phases. Compared with YSZ materials, RE 2 HE 2 O 7 ceramics exhibited a much lower glass-like thermal conductivity (1.19–1.68 W m −1 K −1 , 100–900 °C) and comparable thermal expansion coefficients (8.67–10.85 × 10 −6 K −1 , 1200 °C). Furthermore, due to grain refinement caused by the competition of two phases, the Vickers hardness (10.29–13.85 GPa) of RE 2 HE 2 O 7 ceramics is improved. The results indicate that dual-phase high-entropy RE 2 HE 2 O 7 ceramics are promising candidate materials for the next generation of thermal barrier coatings.
研究领域:
材料科学
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陶瓷工程
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DOI
高影响因子
International Journal of Applied Ceramic Technology
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2023
·Vol. 20
·期 4
·2392-2400
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IF 2.1
Zicheng Wei,Qingqing Yang,Bin Meng,Chen Li,Xinyu Ping,Congcong Fang,Han Zhang
Six rare-earth tantalate high-entropy ceramics of (5RE .2 )Ta 3 O 9 (RE represents any five elements selected from La, Ce, Nd, Sm, Eu, Gd) were designed and prepared by spark plasma sintering process at 1400°C in this study. The (5RE .2 )Ta 3 O 9 ceramics only consist of a single-phase solid solution with perovskite structure. Their relative densities are all above 90%, and the average grain size is in the range of 1.47–2.92 μm. The thermal conductivity of (5RE .2 )Ta 3 O 9 ceramics is in 2.24–1.90 W m −1 K −1 (25°C–500°C), which is much lower than that of yttria-stabilized zirconia. In six samples, (La .2 Nd .2 Sm .2 Gd .2 Eu .2 )Ta 3 O 9 possesses a thermal conductivity of 1.90 W m −1 K −1 , a thermal expansion coefficient of 3.47 × 10 −6 K −1 (500°C), a Vickers hardness of about 7.33 GPa, and a fracture toughness of about 5.20 MPa m 1/2 , which are suitable for its application as thermal barrier coatings.
研究领域:
材料科学
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热力学
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DOI
高影响因子
Journal of Materiomics
·
2023
·
IF 9.4
Fangze Chen,Dacheng Zhou,Xueqing Xiong,Juntao Pan,Donglin Cai,Ze Wei,Xiyong Chen,Yihui Liu,Nengneng Luo,Jialin Yan,Toyohisa Fujita
A series of single-phase double perovskite Pr 1- x Gd x BaCo 2- y Fe y O 5+ δ ( x = 0, 0.5 and 1, 0 ≤ y ≤ 1) materials were engineered through A/B site co-doping strategy to improve the mechanical, electrical and electrochemical properties as potential cathode materials for the application of intermediate solid oxide fuel cells (IT-SOFCs). The corresponding thermochemical stability, thermal expansion behavior, electrical conductivity and cathodic polarization resistance of the materials were systematically investigated. It was found that the A-site dual lanthanide doped Pr 0.5 Gd 0.5 BaCo 2 O 5+ δ (PGBCO) exhibits improved electrical conductivity, reduced thermal expansion, and comparatively low electrochemical polarization resistance versus single lanthanide double perovskite, PrBaCo 2 O 5+ δ (PBCO) and GdBaCo 2 O 5+ δ (GBCO) materials. Further investigation on the effect of B-site Fe-doping on Pr 0.5 Gd 0.5 BaCo 2- y Fe y O 5+ δ (PGBCF- y , 0 ≤ y ≤ 1) reveals that all the PGBCF- y compositions exhibit excellent chemical stability with Gd-doped ceria (GDC) at operating temperatures not higher than 1 100 °C. Besides, doping of Fe in B-site can effectively reduce the thermal expansion coefficients (TECs) of the Pr 0.5 Gd 0.5 BaCo 2 O 5+ δ ceramics at 30–1 000 °C. And the electrochemical impedance spectra (EIS) results show that the PGBCF- y |GDC| PGBCF- y symmetric cells have acceptable low area specific polarization resistances. Further examination of the cathodic polarization and characteristic capacitance from the AC impedance spectra by employing the relaxation time distribution (DRT) method demonstrated that charge transfer is the dominating sub-process for the oxygen transport through the materials.
研究领域:
材料科学
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燃料电池研究
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Sehreish Abrar,Zhuang Ma,Ling Liu,Faisal Nazeer,Abdul Malik
In this work, novel equiatomic high entropy (Dy 1/4 Ho 1/4 Tm 1/4 Yb 1/4 ) 2 Si 2 O 7 or (4RE 1/4 ) 2 Si 2 O 7 ceramic pyrosilicate was fabricated through a single solid solution method to use as environmental barrier coating. The SEM analysis of high entropy powders shows the homogenous mixing and XRD proves the formation of single β-phase after milling and sintering. The coefficient of thermal expansion was reported as (2.3–4.8 × 10 −6 K −1 ) from 400 K −1 to 1723 K −1 . The ultra-low thermal diffusivity (0.4 mm 2 s −1 ) and thermal conductivity (0.8 W/m°C) were reported at 1500 °C for this novel HE ceramic disilicate. The as fabricated (4RE 1/4 ) 2 Si 2 O 7 pyrosilicate shows an excellent CMAS resistant for even up to 48 h and negligible amount of Ca is able to penetrate in the substrate. Rare earth disilicate species with intermediate radii such as Tm 3+ helps in maintaining phase stability along with passive element Yb 3+ of smaller radii which also protect the interface from severe CMAS attack. However, the rare earth species with larger radii such as Dy 3+ and Ho 3+ actively take part in apatite formation leading to reduced corrosion activity of CMAS melt by changing its composition. This result confirms the application of (4RE 1/4 ) 2 Si 2 O 7 as a potential candidate to be used as protecting coating material in harsh combustion environments.
研究领域:
材料科学
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高温材料
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DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2023
·
IF 2.6
Jiale Wang,Guang Yao,Dong Hu,Sheng Huang,Junqi Liu,Quan Zhu
In order to investigate the interactive effect on the density of two-component mixtures, six mixtures of methylcyclohexane(1) + n-dodecane(2)/n-tetradecane(2)/n-hexadecane(2) and ethylcyclohexane(1) + n-dodecane(2)/n-tetradecane(2)/n-hexadecane(2) were measured by using the Anton Paar DMA 4200 M densimeter and a hand-operated pressure pump in the temperature and pressure ranges of T = 280 to 423.15 K and P = 0.1 to 9 MPa, respectively. Additionally, the combined standard uncertainty in the density of binary mixtures with n-hexadecane is uc(ρ) = 1.543 kg/m3, and for other mixtures, it is uc(ρ) = 1.541 kg/m3. The experimental data were successfully correlated with the empirically modified Toscani–Szwarc equation of state with a maximum regression deviation of less than 1.0630 kg/m3 for all the binary mixtures. On the basis of the experimental data and parameters of the regression model, isobaric thermal expansivity and isothermal compressibility were calculated and exhibited nonlinear behavior against the mole fraction, which is due to different molecular interactions between the two components.
研究领域:
物理化学
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热力学
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Weijun Wang,Xihang Pei,Xintian Li,Wei Wen
Thermal barrier coatings improve the energy efficiency of industrial and aerospace gas turbines by increasing operating temperatures. In this study, two types of high-entropy thermal barrier coating materials were synthesized by solid-phase reactive sintering: (La 0.2 Nd 0.2 Gd 0.2 Yb 0.2 Y 0.2 ) 2 Ce 2 O 7 (5RC) and (La 0.2 Nd 0.2 Gd 0.2 Yb 0.2 Y 0.2 ) 2 CeZrO 7 (5RCZ). Both samples remain in a single-phase fluorite structure after annealing at 1400 °C for 100 h, showing excellent phase stability. Specifically, 5RC exhibits no chemical reaction with α-Al 2 O 3 following annealing at 1200 °C for 4 h and demonstrates outstanding chemical compatibility. The thermal expansion coefficients (TECs) for 5RC and 5RCZ are 11.5 × 10 −6 K −1 and 10.4 × 10 −6 K −1 at 1200 °C, respectively. Furthermore, the TEC of 5RCZ shows stable performance, demonstrating no significant fluctuations at lower temperatures. Due to the high entropy effect and lattice distortion, 5RC and 5RCZ exhibit excellent thermal insulating properties. At low-temperature range, 5RCZ has lower thermal conductivity than 5RC due to a more significant disorder in ion radius and atomic mass. At 1200 °C, the thermal conductivity of 5RCZ (1.406 W m −1 K −1 ) is greater than that of 5RC (1.263 W m −1 K −1 ), likely because of 5RC's higher infrared emissivity. In conclusion, the high-entropy rare earth ceramics 5RC and 5RCZ exhibit significant potential for use as thermal barrier coating materials.
研究领域:
材料科学
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热力学
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DOI
高影响因子
MATERIALS CHARACTERIZATION
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2024
·
IF 4.8
Qian Ma,Yewei Wang,Anze Shui,Chao He,Hulei Yu
A novel compositionally-complex flexible (Mg 0.2 Al 0.2 Fe 0.2 Ni 0.2 Co 0.2 ) 2 Ti 2.8 O 8 (abbreviated as CCC) ceramic with pseudobrookite structure was synthesized by solid-state reaction method. As compared to the fabrication process of flexible aluminum titanate ceramic (C. Babelot, 2011), the sintering temperature was significantly reduced from 1600 °C to 1200 °C by co-doping. And, the combinations of displacement (0.11–0.25 mm) and bending strength (10–40 MPa) were achieved by controlling the sintering condition . Among these, the specimen sintered at 1200 °C for 2 h (abbreviated as CCC-1200-2) presents a single-phase crystal structure and uniform elemental distribution. After that, its near-zero thermal expansion coefficient of 0.47 × 10 −6 K −1 at low temperature was obtained and the nonlinear thermal expansion behavior was observed. Lastly, the thermal stability of sample CCC-1200-2 was checked out by annealing the samples between 900 °C and 1600 °C for various times up to 100 h. As a result, this study successfully fabricated the flexible CCC ceramics with improved mechanical properties, high thermal stability, and low sintering requirements, providing a new technology strategy for pseudobrookite-type ceramics and compositionally-complex ceramics fabrication.
研究领域:
材料科学
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无机化学
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DOI
高影响因子
Science China-Materials
·
2023
·Vol. 66
·期 7
·2795-2802
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IF 8.1
Zheng Zhe-Xiong,Qiu Zhi-Xin,Xie Chao-Hong,Zhang Yang-Ping,Jiang Xiao-Ming,Liu Bin-Wen,Guo Guo-Cong
Strong second-harmonic generation (SHG) and phase-matchable capability at specific transmittance windows are crucial to the real application of nonlinear optical crystals. Herein, an efficient strategy of introducing Pb 2+ with stereochemically active lone-pair electrons into non-phase-match-able Ga 2 Se 3 via enhancing the anisotropy microstructure is first applied to meet phase-matchable SHG intensity requirements, offering a selenide, namely, PbGa 4 Se 7 , which is designed and synthesized with a diamond-like anionic framework, where Pb 2+ cations reside in a parallel arrangement. As expected, PbGa 4 Se 7 possesses a large SHG coefficient of 3.3 times that of AgGaS 2 under the incident laser of 1910 nm. Moreover, PbGa 4 Se 7 displays a high laser-induced damage threshold of 7.0 times that of AgGaS 2 at 2090 nm, which originates from the low anisotropy of thermal expansion coefficient (0.36) and suitable optical band gap (2.1 eV). Theoretical calculations demonstrate that the considerable phase-matchable SHG response of PbGa 4 Se 7 can be attributed to the synergies of tetrahedral GaSe 4 and pyramid PbSe 3 microstructural blocks with additional anisotropy and polarizability.
研究领域:
材料科学
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光学
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DOI
高影响因子
MATERIALS & DESIGN
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2022
·
IF 9.417
Xiaozhen Wang,Yishi Su,Xiaoshu Wang,Kan Liu,Lanting Zhang,Qiubao Ouyang,Di Zhang
Carbon materials reinforced copper matrix composites with excellent mechanical properties, high thermal conductivity (TC) and suitable coefficient of thermal expansion (CTE) are expected to meet the urgent need for the thermal management materials with structural stability and efficient heat dissipation in civil and military fields. In this work, the tungsten-copper (W-Cu) composite coating was deposited on the graphite flakes (GFs) by the impregnation-reduction and ultrasonic-assisted electroless plating. Meanwhile, the W-Cu coated GFs reinforced Cu matrix composites (GFs(W-Cu)/Cu) were also prepared by the vacuum hot-pressing sintering. Based on the microstructure and surface analysis, the interfacial bonding has changed from the simple mechanical connection to the mechanical-metallurgical synergy. As for the three-point bending and uniaxial tensile tests, the largest in-plane, through-plane flexural strength and tensile strength of the GFs(W-Cu)/Cu composite can achieve the values of 189.6 ± 3.8, 172.3 ± 4.2 and 91.9 ± 2.6 MPa, respectively. Among the GFs(W-Cu)/Cu composites, the ultrahigh in-plane TC and lowest through-plane CTE can reach 929.8 ± 5.0 Wm −1 K −1 and 6.3 ± 0.2 ppmK −1 respectively, and the better thermal response rate can be 0.67 °C·s −1 . In conclusion, an effective way to develop the structural and functional integrated carbon-based thermal management materials can be provided.
研究领域:
材料科学
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热管理材料
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DOI
高影响因子
CERAMICS INTERNATIONAL
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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
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热物理性质
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陶瓷材料
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DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
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2024
·
IF 3.2
Bo Wang,Zihao Pan,Ziyan Zhao,Bo Zhou,Xuejian Liu,Zhengren Huang,Yan Liu
In this paper, we designed two series of the ZnO-B 2 O 3 -SiO 2 (ZBS) glass to explore their applicability for joining AlN ceramic. The density, flexural strength, structure, characteristic temperature, coefficient of thermal expansion (CTE) and crystallization behavior of the ZBS glass with varying ZnO and B 2 O 3 content were systematically studied. The results show that as B 2 O 3 content increase, the glass network is disrupted with the transition from three-dimensional shelf-like structure [BO 4 ] to two-dimensional layers [BO 3 ], increasing the number of the broken bonds, while an increase in ZnO results in a more compact glass network structure. We also found that both glass transition temperature (T g ) and softening temperature (T S ) exhibit a declining trend with the increase in B 2 O 3 and ZnO. Zn 2 SiO 4 and ZnAl 2 O 4 , began to precipitate after heat treatments in all the samples except 60ZnO-30B 2 O 3 –10SiO 2 (abbreviated as B30), where the diffraction peaks do not appear in Zn 2 SiO 4 but in Zn 4 B 6 O 13 . Notably, Zn 2 SiO 4 is the main phase for most samples while the main phase of B30 sample is ZnAl 2 O 4 . The CTE increases from 4.6 to 5.03 (× 10 –6 / °C) and 4.23 to 4.73 (× 10 –6 / °C) with an increase of B 2 O 3 and ZnO content, respectively. Among these, the CTE of B30 sample is compatible with that of AlN ceramic substrate. The optimal shear strength, 60.32±10.26 MPa, was achieved with B30 samples at 750 °C. The high strength was attributed to the interfacial reaction that leads to strong chemical bonding and the uniform distribution of the ZnAl 2 O 4 in the interlayer, which reinforces the strength of the interlayer itself.
研究领域:
材料科学
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无机非金属材料
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DOI
高影响因子
JOURNAL OF MATERIALS ENGINEERING AND PERFORMANCE
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2025
·
IF 2
Zhang Dongbo,Tang Xinyue,Wang Ning,Xiao Mingwei,Yan Jiangrong,Zhang Yongsheng
High-entropy oxides used as thermal barrier coating materials have attracted considerable attention from scientific communities owing to their unique properties, such as low thermal conductivity and good stability at high temperatures. In this study, a new (La 0.2 Gd 0.2 Zr 0.2 Ce 0.2 Ho 0.2 )O 2-δ ((LGZCH)O) fluorite-structured high-entropy oxide was successfully synthesized through a solid-state reaction at 1400 °C. The resulting material demonstrated good phase stability after sintering at high temperatures. The microstructure, microscopic morphology, ionic valence, compositional distribution, optical properties, thermal conductivity, thermal expansion properties, and mechanical properties of (LGZCH)O were investigated. X-ray diffraction results showed that the (LGZCH)O fluorite-structured high-entropy oxide exhibited good stability during sintering at different temperatures with an optimum sintering temperature of 1580 °C. Ce 4+ converted to Ce 3+ at high temperatures. Scanning electron microscopy results showed that the material had a high porosity of approximately 28.9% after sintering at 1580 °C. (LGZCH)O had a higher infrared radiation emissivity of 82.2%-87.6% in the range of 2.5-6.0 μm indicating that it had better thermal radiation shielding performance. After porosity modification, the thermal conductivity ranged from 1.27 to 1.00 W m −1 K −1 from room temperature to 1000 °C, which is considerably lower than that of yttria-stabilized zirconia. Additionally, (LGZCH)O exhibited low coefficients of thermal expansion measuring 9.65 × 10 −6 K −1 and 10.13 × 10 −6 K −1 at 1000 and 1200 °C, respectively. The hardness and Young’s modulus of the bulk (LGZCH)O measured via nanoindentation tests were 8.86 GPa and 153.98 GPa, respectively, which are marginally inferior to those of YSZ. Therefore, (LGZCH)O can be considered a promising candidate material for thermal barrier coatings.
研究领域:
材料科学
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能源工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）