CERAMICS INTERNATIONAL
·
2025
·Vol. 51
·期 20
·30881-30887
·
IF 5.6
Zhenghuang Quan,Zhoufu Wang,Hao Liu,Yan Ma,Shen Zhou,Pingtao Fang,Chao Shu
Yttrium oxide material exhibits excellent vacuum and high-temperature chemical stability, making it an ideal first-choice refractory material for superalloy smelting. However, its poor fracture toughness and low thermal shock stability seriously limit its service life. The ferroelastic toughening phase LaNbO 4 provides excellent fracture toughness due to the ferroelastic domain switching toughening effect. This study focused on yttrium oxide materials, utilizing Y 2 O 3 , La 2 O 3 , and Nb 2 O 5 fine powders as the main raw materials. By incorporating ferroelastic functional unit characteristics, a pre-synthesis LaNbO 4 phase with good intrinsic fracture toughness was introduced into the Y 2 O 3 matrix. The effects of different LaNbO 4 contents on the phase composition, microstructure, mechanical properties, and thermal shock resistance of Y 2 O 3 /LaNbO 4 composite materials were subsequently investigated. The following results were obtained: 1) The optimal pre-synthesis temperature of LaNbO 4 was 1200 °C. At this temperature, LaNbO 4 powder with a fine grain and uniform grain size could be synthesized. 2) The Y 2 O 3 and LaNbO 4 phase resulted in mutual solid solution formation, leading to a change in grain size and mechanical strength of the Y 2 O 3 /LaNbO 4 composite material. 3) The addition of an appropriate amount of LaNbO 4 resulted in the formation of a structure filled with LaNbO 4 grains between the grain boundaries of Y 2 O 3 , effectively improving the fracture toughness and thermal shock stability of the materials. 4) The hardness and strength of LaNbO 4 were lower than the Y 2 O 3 phase, making the selection of LaNbO 4 phase addition to Y 2 O 3 crucial. The excessive addition of the LaNbO 4 phase caused the LaNbO 4 phase in the material to dominate. The hardness and strength of the Y 2 O 3 /LaNbO 4 composite materials were inferior to those of the Y 2 O 3 material, however, the fracture toughness and thermal shock stability improved due to the ferroelastic toughening effect. Therefore, an optimal amount of LaNbO 4 phase should be added to balance the fracture toughness and thermal shock stability of Y 2 O 3 /LaNbO 4 composite materials, while maintaining the hardness and strength of the Y 2 O 3 phase.
研究领域:
无机非金属材料
·
高温结构材料
·
陶瓷增韧
·
材料科学
·
热力学稳定性
·
粉末冶金
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 14
·11174-11183
·
IF 2.779
Cui Zheng,Deng Guowei,Xu Pan,Liu Xiaoyang,Yang Min,Wang Qiliang
In this work, doped and co-doped LaNbO 4 :RE 3+ (RE = Eu, Eu/Tb, Tb) single crystals were prepared by a unique hydrothermal method under the condition of supercritical water and a wide temperature range (823–923 K). The crystal structure of LaNbO 4 :Eu 3+ /Tb 3+ were refined by virtue of the Rietveld method, which can determine the occupation position of dopants. The luminescence properties of Eu 3+ /Tb 3+ -doped LaNbO 4 phosphors were carefully measured and analyzed by diffuse reflectance spectra and ultraviolet. The energy transfer was recognized between host and doped Eu 3+ /Tb 3+ ions based on the luminescence spectra and decay lifetimes, which is dominated by electric multipolar interaction. The results show that the strong emission peaks at 491 nm ( 5 D 4 – 7 F 6 ), 550 nm ( 5 D 4 – 7 F 5 ), 590 nm ( 5 D 4 – 7 F 4 ), 623 nm ( 5 D 4 – 7 F 3 ) can be observed at the optimum reaction temperature of 650 °C, corresponding to CIE coordinates (0.3398, 0.3288). By adjusting the concentration of Eu 3+ /Tb 3+ ions, the emission colors of LaNbO 4 :Eu 3+ /Tb 3+ are varied from blue to pink and to white. Consequently, the synthesis strategy reported herein not only holds extensive promise for expanding the preparation techniques of materials with good luminescence properties but also promotes the practical applications of LaNbO 4 single crystal in low color temperature and high index white light-emitting diode (WLED).
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
SCRIPTA MATERIALIA
·
2014
·
IF 2.968
Ben Ma,Bo Chi,Jian Pu,Jian Li
The morphology of domain structure in LaNbO 4 added to YSZ–NiO composite was examined using a focused ion beam prepared specimen in a transmission electron microscope with a straining stage. It is confirmed for the first time that the morphology is changed under load through domain boundary movement. The driving force for this domain switch is the difference in Gibbs free energy between domains with different crystallographic orientations. This domain switch improves toughness by dissipating stress build-up at the crack tips.
研究领域:
材料科学
·
晶体学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2013
·
IF 3.548
Ben Ma,Bo Chi,Jian Pu,Li Jian
NiO–Y 2 O 3 stabilized ZrO 2 (YSZ) composite is the state-of-the-art material for the anode support of planar solid oxide fuel cells (SOFCs). To improve its fracture toughness ( K C ), lanthanum orthoniobate LaNbO 4 is synthesized by the method of solid state reaction and added to the mixture of YSZ and NiO at the weight ratio of 47:53. The content of LaNbO 4 in the composite is in the range between 5 and 30 wt%. The microstructure of the composites is examined by scanning electron microscopy (SEM); and the chemical compatibility among the components is evaluated by X-ray diffraction (XRD) and energy dispersive X-ray spectroscopy (EDS). Vickers hardness test is performed for estimating the K C of the composites. The results indicate that the K C increases with the addition of LaNbO 4 in the composites; and the toughening effect is associated with the grain-refinement in the composite and the domain switch in the monoclinic LaNbO 4 .
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2014
·
IF 2.726
Ben Ma,Kai Li,Bo Chi,Jian Pu,Jian Li
LaNbO 4 –NiO–Y 2 O 3 stabilized ZrO 2 (YSZ) composites are prepared and investigated as an anode-support material for solid oxide fuel cells. To tailor the coefficient of thermal expansion (CTE), electrical conductivity, fracture strength σ and fracture toughness K IC of the composite, various amounts of LaNbO 4 from 0 to 30 wt.% are added into 53 wt.% NiO–47 wt.% YSZ composite. With LaNbO 4 addition into the NiO–YSZ, σ changes insignificantly, whereas CTE decreases and K IC increases monotonously. For 30 wt.% LaNbO 4 –NiO–YSZ, the CTE is 12.4 × 10 − 6 K − 1 (250–1000 °C), which is much closer to that of YSZ, and the K IC is 3.1 MPa-m 1/2 , which is 42% increase compared with that of the NiO–YSZ. The increase in fracture toughness is possibly due to the domain switch within LaNbO 4 and the overall grain refinement of the composite. The electrical conductivity of the reduced composites decreases with increasing the amount of LaNbO 4 and shows metallic conducting behavior with temperature.
研究领域:
材料科学
·
能源工程
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Huining Huang,Tao Wang,Haifeng Zhou,Dapeng Huang,Yaqiang Wu,Guangjun Zhou,Jifan Hu,Jie Zhan
Novel green-emitting Yb 3+ and Tb 3+ co-doped LaNbO 4 particles were prepared through a facile sol-gel and combustion method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric and differential thermal analysis (TG-DTA), up-conversion luminescence (UCL) with different powers and varied concentrations, and luminescent lifetimes were employed to test the prepared samples. The XRD data exhibit that a sample with high crystallinity can be acquired at 1000 °C. FE-SEM images show homogeneous and spherical grains after Yb 3+ and Tb 3+ are co-doped in the LaNbO 4 samples. TG-DTA reveals that the LaNbO 4 synthetic process is accompanied by a temperature increase. In our work, we utilize a 980 nm laser to excite Yb 3+ ions to achieve the 2 F 7/2 → 2 F 5/2 transition, and the LaNbO 4 :Yb 3+ , Tb 3+ sample exhibits intense green emission. Luminescent spectra at different powers demonstrated the two-photon absorption process; meanwhile, the corresponding energy transfer mechanism from Yb 3+ to Tb 3+ and the emission of Tb 3+ under 980 nm laser excitation was described via an energy level diagram. Moreover, concentration-dependent up-conversion luminescent properties were systematically explored, and it was confirmed that LaNbO 4 :0.15Yb 3+ ,0.02Tb 3+ exhibits the strongest luminescent properties. In particular, as the content of Yb 3+ ions increases, the 5 D 4 → 7 F 6 transition quickly becomes stronger, resulting in the emitted color shifting from green to blue. Therefore, the emitted color can be tuned by adjusting the content of Yb 3+ ions. The excellent up-conversion emission properties of the obtained samples allow for their potential application in the fields of 3D display technologies and solid-state lasers.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Meiting Li,Bingxin Yuan,Xiangyang Zheng,Bo Chen,Chi Zhang,Xuejiao Wang,Ji-Guang Li
A series of LaNbO 4 :RE 3+ (RE = Tb and Eu) phosphors were successfully synthesized via a calcination-assisted hydrothermal reaction, where the vital roles of solution pH, calcination temperature and NbO 4 3− /La 3+ molar ratio in phase/morphology evolution of LaNbO 4 nanocrystals were elaborated. It was unambiguously demonstrated that monoclinic LaNbO 4 can be crystallized at solution pH = 8–13 after calcination at 900 °C. With pH = 10 precursor for example, higher calcination temperature led to phase transformation from orthorhombic to monoclinic structure. LaNbO 4 nanoparticles exhibit self-activated broad-band excitations ( 1 A 1 → 1 T 1,2 ) and emissions ( 3 T 2,1 → 1 A 1 ) within the NbO 4 3− ligand. Intriguingly, Tb 3+ /Eu 3+ incorporations allow for phase tailoring and full-visible-spectrum color-tunable luminescence, where the latter benefits from the effective NbO 4 3− → Tb 3+ → Eu 3+ energy transfer. LaNbO 4 :0.01 Tb 3+ ,0.01Eu 3+ phosphor exhibits stronger white-light emission, which gradually drifts to yellowish green at high heating temperature. This phosphor is an attractive candidate for optical thermometers and warm pc-WLED owning to excellent thermal stability, a low correlated color temperature of ∼5694 K and a high color rendering index of ∼90.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xiangling Tian,Zhijun Ma,Jianrong Qiu,Rongfei Wei
Optical fibers have been formed by replacing precursor glass core with precursor ceramic core, in which drawing process, the precursor ceramic melted to fill the space of the core region while the clad glass was softened. Nd 3+ doped LaNbO 4 nanocrystals were precipitated in the core after heat treatment. X-ray diffraction, Raman spectra, high-resolution transmission electron microscopy, electron paramagnetic resonance, optical microscope, and photoluminescence were used to characterize the obtained fiber. No crystallization, cracking, bubble, or undissolved substance is observed in the core region of precursor fiber. Nd 3+ doped LaNbO 4 nanocrystals are precipitated in the core region after thermal treatment. Under the pumping source of 808 nm, three emission bands located at ∼887 nm, ∼1064 nm, and ∼1337 nm are observed, which makes this GC fiber a promising material for the NIR fiber amplifier.
研究领域:
材料科学
·
光学
·
光子学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）