JOURNAL OF LUMINESCENCE
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2014
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IF 2.367
Jiansheng Huo,Jiadan Zhu,Shunhua Wu,Haijie Zhang,Qianming Wang
Red emissive phosphors of YTa 1− x Nb x O 4 :Eu 3+ ( x =0–1) have been successfully synthesized by a molten salt method. Powder characteristics were studied by X-ray diffraction, scanning electron microscopy and photoluminescence spectroscopy. The effects of Nb concentration ( x ), flux nature and firing temperature on photoluminescence behavior of YTa 1− x Nb x O 4 :Eu 3+ were extensively investigated. The results showed that the photoluminescence spectra of the samples exhibited strong red emissions (615 nm) upon the ultraviolet excitation and the emission intensities strongly dependent on the host-lattice composition and particle morphology .
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
Coatings
·
2023
·Vol. 13
·期 2
·252
·
IF 3.4
Yunzhang Li,Meng Zhou,Yi Zhang,Hanjing Zhu,Xianhua Zheng,Shengli Liang,Shunlong Tang,Baohong Tian,Yong Liu,Xu Li,Alex A. Volinsky,Chenglin Zheng
With the massive penetration of electronics into human life, higher demands are placed on electrical contacts. Among them, the lifetime of electrical contacts and safety are the most concerning. In this research, Al2O3-Cu/25Mo5Ta and 0.5Y2O3/Al2O3-Cu/25Mo5Ta composites were prepared by using ball milling and powder metallurgy methods. The two composites were subjected to 10,000 contact opening and closing electrical contact experiments and the arc duration and arc energy were analyzed. The results show that the addition of Y2O3has a slight effect on the mechanical properties of the Al2O3-Cu/25Mo5Ta composites but has a significant effect on the electrical contact performance. Y2O3can reduce the mass loss of the electrical contacts during the electrical contact process, which prolongs their service life. The addition of Y2O3decreased the average arc duration and arc energy of the electrical contact material by 21.53% and 18.02%, respectively, under the experimental conditions of DC 30 V, 10 A. TEM results showed that nanoscale YTaO4with excellent thermal stability was generated during the sintering process, which has a positive effect on the electrical contact performance of the composites.Keywords:copper matrix composites;electrical contact;arc erosion behavior;yttrium tantalate
研究领域:
材料科学
·
电气工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2022
·
IF 10.319
Cheng Luo,Cong Li,Ke Cao,Junbao Li,Junhui Luo,Qinghua Zhang,QianQian Zhou,Fan Zhang,Lin Gu,Li Yang,Yichun Zhou
Yttrium tantalate (YTaO 4 ) is the next generation of higher service temperature thermal barrier coatings (TBCs) materials due to its smaller volume effect in phase change, lower thermal conductivity and unique ferroelastic domain structure. However, the low fracture toughness limits its application. We first characterized the diffraction patterns of variants, and two variants (M 1 and M 2 ) observed in transmission electron microscopy (TEM) results were determined from four possible variants by mechanical derivation. The role of Zr 4+ doping in ferroelastic toughening was explained in detail. With the increase of Zr 4+ doping concentration, the monoclinic angle β and the domain rotation angle α decrease, respectively. The spontaneous strain component and the principal strain in the main space also have a similar decreasing trend. The decrease of the ferroelastic domain inversion energy barrier is beneficial to the improvement of fracture toughness . Combining the results of Vickers indentation, we found that Zr 4+ could be enriched at the domain boundary to inhibit the generation of cracks. An appropriate amount of Zr 4+ is conducive to the improvement of fracture toughness, and the excessive Zr 4+ will reduce the fracture toughness due to the generation of by-product t -ZrO 2 . So, the optimal composition is Y 0.44 Ta 0.44 Zr 0.12 O 2 and the best fracture toughness (2.9–3.8MPa m 1/2 ) is equivalent to the commercial 8YSZ. This result will promote the application of a new generation of TBCs.
研究领域:
材料科学
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表面工程
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结构陶瓷
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热障涂层技术
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固态相变
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力学性能
✓ 已验证
DOI
高影响因子
International Journal of Minerals Metallurgy and Materials
·
2025
·Vol. 32
·期 6
·1441-1450
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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
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机械工程
✓ 已验证
产品关联
DOI
高影响因子
Metals
·
2025
·Vol. 15
·期 3
·307
·
IF 2.5
Ziyang Ruan,Zifan Zhao,Jing Feng
Rare-earth tantalates (RETaO4) are considered as a type of emerging thermal barrier coating materials applied to the hot components of gas turbines and aerospace engines due to their excellent thermal stability, high-temperature fracture toughness, corrosion resistance and extremely low thermal conductivity. However, the relatively low hardness and thermal expansion coefficients may limit their service lifetime in a harsh engine environment. To address the current limitation of rare-earth tantalates and further optimize the mechanical and thermal properties, the defective fluorite-structured Y₂Zr₂O₇ (YZ) was introduced as a second phase into the YTaO4(YT) matrix to form YT1−x–YZx(x = 0, 0.25, 0.5, 0.75, 1) composite ceramics in this work. The mechanical and thermal properties of YT1−x–YZxcomposite ceramics are significantly improved compared to pure-phase YTaO4ceramics. The Vickers hardness of YT1−x–YZx(x = 0.25, 0.5, 0.75) composite ceramics is 9.1~11.3 GPa, which are 2~2.5 times higher than that of YTaO4(4.5 GPa). Among them, YT0.75–YZ0.25exhibits a maximum fracture toughness (3.7 ± 0.5 MPa·m1/2), achieving a 23% improvement compared to YTaO4(3.0 ± 0.23 MPa·m1/2) and a 118% improvement compared to Y2Zr2O7(1.73 ± 0.28 MPa·m1/2). The enhancement is attributed to the combined effect of the intrinsic strengthening of the second phase, as well as the residual stress and grain refinement caused by the introduction of a second phase. Additionally, the thermal expansion coefficients of YT1−x–YZxcomposite ceramics at 1673 K range from 10.3 × 10⁻⁶ K⁻1to 11.0 × 10⁻⁶ K⁻1, which is also higher than that of YTaO4(10.0 × 10−6K−1). Consequently, the superior mechanical and thermal properties indicate that YT–YZ composite ceramics possess promising application prospects for thermal barrier coatings.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）