JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2023
·
IF 5.7
Xiaoyu Li,Naichao Chen,Jin Cheng,Xianqiang Chen,Biao Guo,Fei Jin,Hong Wang
The Li 2 MoO 4 -MoO 3 ceramic system can be densely sintered at ultralow temperatures (< 500 °C). However, the phase composition of the Li 2 MoO 4 -MoO 3 system at a molar ratio of 1:1 has always been controversial. In this study, the traditional solid-state method was used to synthesize Li 4 Mo 5 O 17 (400 °C, 10 h) and Li 2 Mo 2 O 7 (350–400 °C, 4 h). Li 2 Mo 2 O 7 is an intermediate phase that can be converted to Li 4 Mo 5 O 17 at higher temperatures. The Li 4 Mo 5 O 17 ceramic could be sintered and densified at only 490 °C in air, exhibiting a relative density of 95.6% and excellent dielectric properties , including ε ′= 12.79 and tan δ = 0.0004 at 1 GHz. Such an ultralow sintering temperature and dielectric loss indicate that the Li 4 Mo 5 O 17 ceramic is a good candidate for high-frequency capacitance applications.
研究领域:
材料科学
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电子材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 107
·期 7
·4878-4890
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IF 3.5
Qi Yuan,Yutong Meng,Tao Wang,Wencai Hu,Sen Wang,Gaobin Liu,Qiyao Wang,Kuoming Song,He Zhao,Shuai Yan,Xin Li
Li 2 (Mg 1– x Cu x ) 2 Mo 3 O 12 (0 ≤ x ≤0.1) ceramics were prepared using the conventional solid-phase method to study the effect of the Cu 2+ substitution for Mg 2+ on the sintering behavior, crystal structure, and microwave dielectric properties of ceramics. The experimental results show that the substitution of Cu 2+ for Mg 2+ reduces the sintering temperature of the ceramics to 550°C. X-ray diffraction patterns show that the introduction of Cu 2+ does not produce a new phase, but rather promotes the formation of Li 2 (Mg 1– x Cu x ) 2 Mo 3 O 12 solid solution. The microwave dielectric properties of the ceramics are influenced by the cell parameters, bond lengths, and structural stability. However, Cu 2+ creates oxygen vacancies during sintering, thereby deteriorating the dielectric properties ( Q × f decreases). The microwave dielectric properties of Li 2 (Mg 1– x Cu x ) 2 Mo 3 O 12 ceramics are optimal at a sintering temperature of 550°C and x = 0.02, with ε r = 9.17, Q × f = 7960 GHz, and τ f = –58.77 ppm/°C. Additionally, these ceramics are compatible with Al electrodes.
研究领域:
材料科学
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晶体学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2024
·
IF 5.8
Juan Wang,Xiaoyu Wang,Yongzhao Yang,Qianlong Fu,Feng Hu,Zijian Zhang,Shuang Li
Silicon carbide (SiC) ceramic membranes are promising components for the efficient treatment of various wastewaters in membrane-based techniques. However, the high preparation temperature and then the high production cost inhibits their large-scale application. Here, an ultra-low temperature sintering process was proposed to prepare SiC ultrafiltration membrane. When the ceramic membrane was heated at 600 °C in air, a selective layer comprised of α-SiC and β-SiC formed without the emergence of crystalline silica. The thickness of the membrane layers was determined by the solid content and viscosity of the slurry. Well-dispersed SiC grains and homogeneous-distributed pores formed in the selective layers when using 100 nm SiC powders. The water flux and emulsion flux were investigated to verify the permeability of the ceramic membrane. Thus, this work proposes an energy-saving process for the preparation of SiC UF membrane and achieves the preparation of SiC UF membrane at ultra-low temperature.
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Xiaofei Wang,Jinping Li,Cheng Yang,Hui Zhang,Songhe Meng
It is difficult to achieve densification for metastable ceramics at ultra-low temperatures sintering due to insufficient sintering kinetics. Here, one strategy is proposed to enhance ceramic densification based on the principles of grain refinement and interface modification, in conjunction with a cold sintering process (CSP, 190 °C, 1 − 240 min, and 350 MPa) to achieve ceramic fabrication in a solid-liquid coexistence sintering environment. ZrW 2 O 8 @ZrO 2 metastable composites as an example to demonstrate the effect of surfactant on grain tailoring and interfacial structure design during the hydrothermal assembly. The results show that the densities and mechanical strengths of the composite ceramics were significantly improved after the shape tailoring. Furthermore, the shape-tailored strawberry-like nanostructure enables the ZrW 2 O 8 to be split into smaller individual units, which allows the composites to achieve a high-level of zero thermal expansion ( α ‾ = 0.045 × 10 −6 °C −1 [-10 − 300 °C]). Such a methodology can effectively solve ceramic densification in ultra-low temperature sintering and provide a practical path for the fabrication of metastable ceramics.
研究领域:
材料科学
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无机化学
✓ 已验证
DOI
高影响因子
Materials Today Communications
·
2022
·
IF 3.662
Chen Li,Yahan Liu,Mengjiao Chi,Xinjiang Luo,Bing Liu,Minmin Mao,Hadi Barzegar Bafrooei,Ge Wang,Ehsan Taheri-Nassaj,Kaixin Song
Highly-density Zn 3 B 2 O 6 (ZBO) ceramics were firstly prepared via a two-step cold sintering and ultra-low temperature sintering process (CSP-plus ULTCC post annealing). In this study, pre-densified ZBO ceramics (relative density∼ 92 %) is initially obtained under the condition of 200 ℃/60 min/300 MPa via CSP using acetic acid as a liquid phase, yielding microwave properties of ε r = 5.05, Q × f = 6353 GHz and τ f = −69.51 ppm/℃. After annealing at 550 ℃, relative dielectric properties are significantly improved, resulting in the microwave dielectric properties of ε r = 5.95, Q × f = 20620 GHz, τ f = −67 ppm/℃ achieved in a ZBO ceramics with relative density> 95 %. Many fine grains are observed to precipitate between the larger grains of cold-sintered ZBO ceramics, as evident by SEM images, exhibiting disordered grain and porosity distribution. At contrast, a uniform microstructure with fine grain and less porosity are observed after annealing procedure. The densification process of ZBO ceramics prepared by this method is further investigated to validate cold sintering "dissolution-precipitation" mechanism, as a critical factor, for promoting the densification of ZBO ceramics.
研究领域:
材料科学
·
电子材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 107
·期 12
·8281-8290
·
IF 3.5
Shumin Duan,Zhenjun Qing,An Liu,Haiyan Li,Yan Xue
Ultra-low temperature sintered ceramics, Li 2 (Mg 1− x Ca x ) 2 (MoO 4 ) 3 ( x = 0.025–0.100), were synthesized using the solid-phase method. XRD analysis revealed that adding Ca 2+ increased the second-phase CaMoO 4 content. Particularly, Li 2 (Mg 0.975 Ca 0.025 ) 2 (MoO 4 ) 3 ceramics exhibited excellent properties: ε r = 9.31, Q × f = 55,400 GHz, and τ f = −38.9 ppm/°C. Incorporating Ca 2+ significantly improved the performance of ceramics. The microwave dielectric properties of Li 2 (Mg 0.9 Ca 0.1 ) 2 (MoO 4 ) 3 ceramics sintered at 650°C showed enhancements: ε r of 9.55, Q × f of 63,500 GHz, and τ f of −10.8 ppm/°C. The rise in ε r can be attributed to polarizability, while a higher packing fraction led to a larger Q × f value, and the reduced distortion of the [Li/Mg/CaO 6 ] octahedra enhanced the τ f value. Moreover, the increased of CaMoO 4 also positively influenced the ceramic's properties. Furthermore, in accordance with the principles of complex chemical bonding, the elevation of ionicity, lattice energy, and bond energy of the Mo–O bond contributed to the enhancement of ε r , Q × f , and τ f , respectively. Raman spectroscopy showed a positive correlation between dielectric loss and full width at half maximum of the Raman peak. Good chemical compatibility between silver and Li 2 (Mg 0.9 Ca 0.1 ) 2 (MoO 4 ) 3 ceramic was demonstrated through our co-firing experiment.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhenjun Qing,Huapeng Zou,Xin Zhou,Haiyan Li,Yingxiang Li
This paper presents a study on the microwave dielectric properties of K 2 Bi(PO 4 )(MoO 4 ) (KBPM) ceramics prepared through the solid-state method. XRD refinement analysis confirmed the presence of the orthorhombic crystal structure of the ceramics, belonging to space group Ibca (#73), with only the K 2 Bi(PO 4 )(MoO 4 ) phase observed. The ceramic sintered at 625 °C exhibited the most compact structure and demonstrated excellent microwave dielectric properties : ε r = 8.37, Q × f = 42,500 GHz, and τ f = −78.2 ppm/°C. The measured value of ε r closely matched the theoretical value, indicating a strong correlation between polarization and the ε r . The Q × f value was found to be influenced by the packing fraction, while the τ f value showed an inverse relationship with the Mo–O bond valence. Analysis based on the P–V-L theory revealed the interconnected nature of ionicity, lattice energy, bond energy, and the ε r , Q × f , and τ f of the ceramics. Raman spectroscopy provided valuable insights into the lattice vibrations of the ceramics. Additionally, the KBPM ceramics were found to possess favorable chemical compatibility with silver, suggesting their potential application as ultra-low-temperature co-fired ceramics.
研究领域:
材料科学
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无机化学
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物理学
✓ 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）