CERAMICS INTERNATIONAL
·
2026
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IF 6
Leibo Deng,Tianyi Li,Yahui Zhou,Wenjing Zhang
The harmless treatment of Cr-containing solid waste remains a critical environmental challenge. Herein, Cr 2 O 3 -doped CaO–MgO–Al 2 O 3 –SiO 2 glass-ceramics with varying Na 2 O contents were prepared via a melting method. The study focuses on how Na 2 O regulates the glass network, crystallization behavior, and Cr immobilization efficiency. With increasing Na 2 O content, the degree of depolymerization (DOD) of the parent glass increases from 1.76 to 1.99, while the crystallization activation energy decreases accordingly. The optimal formulation is achieved at 1 wt% Na 2 O combined with a two-stage heat treatment (nucleation at 720 °C for 2 h, followed by crystallization at 850 °C for 2 h). Under these conditions, the glass-ceramic exhibits the lowest Cr leaching concentration of 0.031 mg/L, far below the regulatory limit of 5 mg/L. The dominant crystalline phases are diopside and a spinel solid solution, where Cr 3+ is stably incorporated into the spinel. These findings demonstrate that controlled Na 2 O addition provides an effective compositional lever for optimizing both crystallization kinetics and heavy metal immobilization, offering a sustainable pathway for valorizing Cr-containing wastes into high-performance glass-ceramics.
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高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 11
·6953-6964
·
IF 4.186
Yuchao Qiu,Junjie Shi,Bin Yu,Changle Hou,Jingjing Dong,Song Li,Yumo Zhai,Jianzhong Li,Changsheng Liu
The recycling of titanium from titania-bearing slag is an important part of the circular economy; however, the yield of titania is restricted due to the lack of fundamental thermodynamic data. In the present work, the equilibrium phase relations of MgO–Al 2 O 3 –TiO 2 system in air at 1600°C have been determined using a high-temperature equilibration-quenching technique followed by X-ray photoelectron spectroscopy, scanning electron microscopy-energy-dispersive X-ray spectrometry, and X-ray diffraction. Ti 4+ was confirmed as the stable valence of titanium, and the rutile and spinel solid solution phases were detected to be coexisting with pseudobrookite solid solution phase, respectively. The formation principles of pseudobrookite and spinel solid solutions were confirmed in view of the corresponding crystal structure and the composition substitution relationship of the oxides at 1600°C. However, great discrepancies were found from the comparison of the present experimental results with the thermodynamic calculations and the literature results, and the present equilibrium phase relations are therefore significant for updating the present titania related thermodynamic database for a superior prediction of the thermodynamic behaviors of relevant process.
研究领域:
材料科学
·
冶金工程
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高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2026
·
IF 3.1
An Zhuoqing,Liang Weiwen,Gao Yuan,Chen Jiajing
The viscosity of the CaO–MgO–Al 2 O 3 –SiO 2 system containing La 2 O 3 and Fe 2 O 3 was measured by rotation, hot-stage microscopy and hot-stage load methods to investigate the rheological behavior across multiple temperature ranges. In-situ high temperature Raman spectroscopy was employed to quantitatively analyze the microstructure. The results show that with the La 2 O 3 /Fe 2 O 3 ratio varying from 2/0 to 0/2, the viscosity decreases gradually through the multiple temperature ranges, and the viscous flow activation energy also gradually decreases. As the ratio of La 2 O 3 /Fe 2 O 3 decreases, the relative contents of Q 0 , Q 1 and Q 2 increase gradually, and the relative contents of Q 3 and Q 4 decrease significantly. This indicates that both La 2 O 3 and Fe 2 O 3 act as network modifiers and simplify the glass network structure, resulting in a decrease in the degree of network polymerization and viscosity over the multiple temperature range. Compared to La 2 O 3 , Fe 2 O 3 is a more effective network modifier, as it breaks up the silicate network more efficiently and results in a lower overall viscosity. In addition, the microstructure of the melts was quantitatively analyzed by NBO/ T , and a quantified relationship among viscosity, microstructure and temperature was given.
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高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
·
2026
·
IF 9.2
Hailong Fang,Shangzhen Feng,Jie Yang,Huanjin Jiang,Wenhao Wang,Rijie Wang,Jixiang Chen
MgO–Al 2 O 3 supported Ni and Ni–Mo bimetallic catalysts (referred as Ni/MgAl and Ni x Mo/MgAl with the Ni/Mo atomic ratio of x, respectively) were prepared by the co-precipitation method and tested for the dry reforming of methane (DRM) on an atmospheric quartz fixed-bed. The XRD, XPS, XAFS and magnetic measurement results demonstrate that the Ni–Mo alloy forms in Ni x Mo/MgAl, which inhibits the sintering of metal particles and enhances the degree of coordination unsaturation of metal sites, and subsequently Ni x Mo/MgAl expose more metal sites than Ni/MgAl. The CO 2 -TPD and TPSR reveals than the presence of Mo promotes the adsorption and dissociation of CO 2 , beneficial to DRM and suppressing carbon deposition. Particularly, compared to that on metallic Ni, the graphitic carbon is remarkably suppressed on Ni–Mo alloy own to the charge transfer from Ni to Mo and the isolated Ni ones by the Mo ones. During DRM, Ni x Mo/MgAl are more active than Ni/MgAl, especially Ni 5 Mo/MgAl, which gives the CH 4 and CO 2 conversions of 82.3% and 87.4% at 800 °C, respectively. Also, Ni 5 Mo/MgAl is more stable than Ni/MgAl, and Ni–Mo alloy structure maintains during the reaction and after the regeneration. In addition, the DRM mechanism dominatingly via the HCOO∗ intermediate species is proposed based on in situ DRIFTS and TPSR.
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高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS B-PROCESS METALLURGY AND MATERIALS PROCESSING SCIENCE
·
2026
·
IF 3.3
Xiao Yang,Zhou Huarui,Wei Junyu,Tang Zhaoyi,Qian Kun,Wang Ning,Zhao Baojun,Liao Jinfa
With the increasing use of high-alumina iron ores in blast furnace ironmaking, the Al 2 O 3 content in the slags has gradually risen to 15 to 20 wt pct, significantly affecting the phase equilibria and flow properties of the slag system. In this study, the phase equilibria in the CaO–MgO–Al 2 O 3 –SiO 2 quaternary system with a fixed Al 2 O 3 /SiO 2 mass ratio of 0.5 (representative of typical high-Al 2 O 3 blast furnace slags) were systematically investigated using high-temperature equilibration and quenching experiments combined with electron probe microanalysis (EPMA). A pseudo-ternary phase diagram CaO–MgO–(SiO 2 +Al 2 O 3 ) was constructed. At a fixed (SiO 2 +Al 2 O 3 ) content of 55 wt pct, the minimum liquidus temperatures for slags with Al 2 O 3 /SiO 2 = 0.5 occur at MgO/CaO ≈ 0.4 (1360 °C), respectively, and the liquidus temperature of the Al 2 O 3 /SiO 2 = 0.4 slag is consistently lower than that of the Al 2 O 3 /SiO 2 = 0.5 slag over the entire MgO/CaO range studied. At fixed MgO/CaO weight ratio of 0.2 and 0.15, the liquidus temperature first decreases and then increases with increasing quaternary basicity (defined as (CaO+MgO)/(SiO 2 +Al 2 O 3 ) by mass). In the conventional basicity range of blast furnace slag (0.95 to 1.05), the liquidus temperature ranges from 1400 °C to 1500 °C, and the high-alumina slag always exhibits a higher liquidus temperature than the ordinary slag. Significant deviations exceeding 50 °C were observed between the experimental liquidus temperatures and the phase equilibria calculated using the FactSage 8.4 thermodynamic database for high‑alumina blast furnace slags. The compositional characteristics of the melilite solid solution were also analyzed using EPMA‑derived compositional data. Strong linear correlations among Al 2 O 3 , SiO 2 , and MgO in melilite confirm the isomorphous substitution mechanism. When the Al 2 O 3 /SiO 2 ratio in the liquid phase is below 0.5, the Al 2 O 3 /SiO 2 ratio in melilite increases sharply with increasing liquid ratio; when the liquid ratio exceeds 0.5, the Al 2 O 3 /SiO 2 ratio in melilite stabilizes within a narrow range of 1.4 to 1.6, indicating that the incorporation of Al 3 ⁺ in the melilite structure approaches an apparent solubility limit.
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高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jian Li,Jia Liu,Yeqing He,Xiaohan Zhang,Yanxiang Jiang,Yang Wang,Wei Sun,Yuanyuan Zhou,Walther Glaubitt,Futian Liu,Haitao Wu,Fei Wang,Ling Li
High-performance dielectric ceramics are vital for next-generation microwave devices, requiring advanced doping and composite strategies to enhance material properties. The (1- x )MgAl 2 O 4 - x Y 3 Al 5 O 12 composite ceramics were found in the MgO-Al 2 O 3 -Y 2 O 3 pseudoternary phase diagram and synthesized via solid-phase reaction. The two phases coexist to improve grain size distribution and achieve a low eutectic temperature, allowing x = 0.1–0.7 samples to gain a dense microstructure ( ρ > 96 %) when sintered at 1650–1670 °C. The semi-coherent interface, coupled with the Mg 2+ /Y 3+ cation transition zone, promotes the formation of a partial solid solution, thereby alleviating interfacial stress at the grain boundaries between MgAl 2 O 4 and Y 3 Al 5 O 12 . Notably, the 0.3MgAl 2 O 4 -0.7Y 3 Al 5 O 12 ceramic exhibits satisfying microwave dielectric properties: ε r = 10.1 ± 0.24, Q × f = 195,000 ± 12,000 GHz, and τ f = −11.9 ppm/°C. In addition to phase composition and microstructure, the enhanced performance can be attributed to the optimized crystal structure. The partial substitution of Y 3+ by Mg 2+ with a smaller radius induced the “rattling” effect and abnormal large permittivity in the [YO 8 ] site. The 27 Al NMR spectra revealed an increase in the Mg-Al inversion degree in the Mg-deficient spinel structure, resulting in the elevated total covalency of the Al-O bond. The structural changes corresponded to a decrease in intrinsic dielectric loss in Mg-Al spinel and an increase in τ f in the Y-Al garnet phase. These findings indicate the (1- x )MgAl 2 O 4 - x Y 3 Al 5 O 12 ceramics have promising applications in the field of HTCC millimeter wave communications.
研究领域:
材料科学
·
电子工程
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高影响因子
CERAMICS INTERNATIONAL
·
2026
·
IF 6
Zhuoqing An,Xiaolong Ni,Zhuang Ma,Yuan Gao,Jiajing Chen
To investigate the effects of La 2 O 3 and Fe 2 O 3 on the structure and high viscosity of the CaO-MgO-Al 2 O 3 -SiO 2 (CMAS) glass system, the microstructure was analyzed using in-situ high-temperature Raman spectroscopy, and the viscosity was measured by high temperature hot-stage. A series of cluster models representing aluminosilicate systems modified by La and Fe ions were constructed, followed by geometric optimization and Raman spectral simulation via quantum chemistry ab initio calculations. The results indicates that the effects of La 2 O 3 and Fe 2 O 3 on both vibrational wavenumber and Raman scattering cross-section (RSCS) followed the order: La < (La + Fe) < Fe. The addition of La 2 O 3 and Fe 2 O 3 loose the glass network structure, and led to a progressive rise in the relative content of Q 0 , Q 1 , and Q 2 units, accompanied by a notable decrease in Q 3 and Q 4 units. Consequently, the high viscosity and viscous flow activation energy decrease with the addition of La 2 O 3 and Fe 2 O 3 , but Fe 2 O 3 has a more pronounced effect. Furthermore, based on the NBO/T for characterizing the microstructure, the relationship between viscosity and microstructure is quantitatively analyzed.
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高影响因子
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