CERAMICS INTERNATIONAL
·
2020
·Vol. 47
·期 4
·4769-4774
·
IF 3.83
Hongfei Liu,Chenjun Zhang,Zhiping Zhang,Xiangdong Meng,Xianghua Zeng
Orthorhombic Sc 2 Mo 3 O 12 films have been successfully prepared via spin coating technique followed by annealing at 500–750 °C. The phase composition, microstructure, morphology and negative thermal behavior of the synthesized Sc 2 Mo 3 O 12 films were investigated. XRD and XPS analysis indicate that as-deposited film is amorphous . Orthorhombic Sc 2 Mo 3 O 12 films can be prepared after post-annealing at 500–750 °C for 1 h. The crystallinity of Sc 2 Mo 3 O 12 films gradually improved with the increase of post-annealing temperature. SEM analysis shows as-deposited film is smooth and compact, and the grain size of Sc 2 Mo 3 O 12 film grows up as the post-annealing temperature increases. Variable temperature XRD analysis demonstrates that the synthesized orthorhombic Sc 2 Mo 3 O 12 films show stable thermo-chemical and anisotropic NTE property in 25–700 °C. The corresponding coefficients of thermal expansion (CTEs) of the orthorhombic Sc 2 Mo 3 O 12 film in a, b and c directions are −6.68 × 10 −6 °C −1 , 5.08 × 10 −6 °C −1 and −4.76 × 10 −6 °C −1 , respectively. The whole unit cell of the orthorhombic Sc 2 Mo 3 O 12 film shrinks and the volumetric CTE of the Sc 2 Mo 3 O 12 thin film is −6.36 × 10 −6 °C −1 , and the linear CTE is about −2.12 × 10 −6 °C −1 ( α v = 3 α l ).
研究领域:
材料科学
·
无机非金属材料
·
功能薄膜
·
热学性能
·
晶体结构
✓ 已验证
DOI
高影响因子
Results in Physics
·
2022
·
IF 4.565
Yige Du,Qilong Gao,Andrea Sanson,Hengli Xie,Yangming Hu,Gaojie Zeng,Juan Guo,Xiao Ren,Erjun Liang
Negative thermal expansion (NTE) is an intriguing physical phenomenon, which is of great significance for the high precision application. In this work, we have realized to broaden the NTE temperature zone in Mg 2 P 2 O 7 -based bulk material by doping Cu atom on the Mg site. A joint study of Raman scattering and X-ray diffraction (XRD) indicates that there are double phases in the NTE temperature zone, and the NTE of Mg 1.9 Cu 0.1 P 2 O 7 bulk material comes from the phase transition of α - and β -phase. The present work provides a way to optimize negative thermal expansion property in phase transition typed materials.
研究领域:
材料科学
·
凝聚态物理
·
无机化学
·
功能材料
·
热学性能
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2023
·
IF 10.9
H.X. Chen,L. Sheng,Z.L. Zhang,X.C. Wen,D.L. Yang,X.Y. Ye,P.Q. Dai
Due to the laminated structure, MAX phases and MAX-phase-like compounds possess outstanding damage tolerance capability with good thermal/electrical conductivity and other charming functional properties, showing a bright future for structural-functional uses. Here, a new MAX-phase-like ternary carbide V 8 P 6 C with layered characteristics was discovered. Contrary to the alternate stacking of hexagonal-arranged M/A/X atom layers in MAX phases, V 8 P 6 C has a layered structure formed by a repeated stacking of the slabs consisting of V 6 C-octahedrons and VP 6 -distorted-octahedrons in three-atomic layers thick. The thermal expansion anisotropy was revealed, with the thermal expansion coefficients (TECs) along a- axis , c- axis, and the average value, equal to α a =8.55(5) μK −1 , α c =10.23(5) μK −1 , and α L =9.14(5) μK −1 , respectively. The dilation along the c -axis was mainly dominated by out-plane V-P bonds between layered slabs. According to the pressure-dependent lattice parameters, the polycrystalline bulk modulus ( B 0 = 185(9) GPa) and high compressibility anisotropy factor ( B a / B c = 1.64) was found. Meanwhile, the second-order elastic constants were calculated, and the elastic moduli, E= 303 GPa, B= 198 GPa, G= 122 GPa, and ν = 0.246, were obtained. And the weak connection between layer slabs by out-plane V1-P bond was revealed by the bond stiffness model, with a bond stiffness close to the M-A bond in MAX phases. Furthermore, good damage tolerance capability was predicted according to Paugh's ratio ( G / B =0.616) and Cauchy pressure ( P a = 0 GPa, P c = -7.5 GPa), even better than those of typical MAX phases. The discovery of V 8 P 6 C provides a new member of MAX-phase-like damage-tolerant ceramic with relatively low density, moderate thermal expansion, and anisotropic compressibility , and the unique layered structure is inspiring for exploring new layered ternary ceramics.
研究领域:
材料科学
·
陶瓷学
·
固态化学
·
材料力学性能
·
热学性能
✓ 已验证
DOI
高影响因子
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Zhiping Zhang,Yuenan Wang,Yang Lei,Fang Zhang,Xiaobing Chen,Hongfei Liu
Negative thermally expanded (NTE) (KMg) x Sc 2-x (WO 4 ) 3 (0 = x ≤ 1.5) ceramics have been prepared via solid-state reaction. X-ray diffraction (XRD) analysis reveals that (KMg) x Sc 2-x (WO 4 ) 3 undergoes a composition-induced phase transition as the (KMg) 3+ -substitution content increases. For x = 0.25, both hexagonal (KMg) x Sc 2-x (WO 4 ) 3 and orthorhombic Sc 2 (WO 4 ) 3 coexisted in the sample. For 0.25 < x ≤ 1, a single-phase, hexagonal (KMg) x Sc 2-x (WO 4 ) 3 , was obtained. When x is further increased to 1.25, monoclinic MgWO 4 impurity was detected in the sample. Meanwhile, as x increases, the grain size of (KMg) x Sc 2-x (WO 4 ) 3 ceramics grows up. Hexagonal (KMg) x Sc 2-x (WO 4 ) 3 ceramics show high densification and strong NTE property. Thermomechanical analysis indicates that the linear coefficients of thermal expansion (CTEs) of hexagonal (KMg) x Sc 2-x (WO 4 ) 3 ceramics decrease from −7.48 × 10 −6 °C −1 to −14.06 × 10 −6 °C −1 with the increase of x. High-temperature XRD analysis reveals that hexagonal (KMg) 0.5 Sc 1.5 (WO 4 ) 3 show an anisotropic NTE. The intrinsic linear CTEs are α a = α b = −6.74 × 10 −6 °C −1 , α c = 11.03 × 10 −6 °C −1 and the volumetric CTE is α v = −2.52 × 10 −6 °C −1 .
研究领域:
材料科学
·
无机非金属材料
·
功能陶瓷
·
热学性能
·
结构与物性
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2024
·Vol. 43
·期 5
·997-1002
·
IF 5.2
Huicai Xie,Jiaxin Jiang,Hao Sun,Zhenxing Li,Jun Liu,Junfeng Wang,Zhaojun Mo,Jun Shen
As one of the core components of a magnetic refrigerator, magnetic refrigeration materials are expected to have not only a considerable magnetocaloric effect but also excellent thermal conductivity . The poor thermal conductivity of many competitive oxide-based magnetic refrigerants, exemplified by EuTiO 3 -based compounds, acts as a major limitation to their practical application. Therefore, improving the thermal conductivity of magnetic refrigeration materials has become a research emphasis of magnetic refrigeration in recent years. In this work, a series of EuTiO 3 (ETO)/Cu composites with different copper additives was prepared using a solid-phase reaction method by introducing appropriate amounts of copper powder. The influence of the introduction of copper on the phase composition, microstructure, thermal conductivity , and magnetocaloric effect of the composites was systematically investigated. Unexpectedly, the thermal conductivity of the composites is enhanced by up to 260% due to copper addition, accompanied by only a 5% decrease in magnetic entropy change and refrigerating capacity. Copper additive forms localized thermal conductive networks and promotes the densification process , resulting in significantly enhanced thermal conductivity of the composites. This work demonstrates the feasibility of improving the thermal conductivity of oxide-based magnetic refrigeration materials by introducing highly thermally conductive substances.
研究领域:
材料科学
·
低温物理
·
磁制冷技术
·
热学性能
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）