CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
He Li,Jingwen Sun,Paolo Colombo
This paper reports the successful preparation of high-strength 3D-printed alumina ceramic cores using stereolithography (SLA) and vacuum sol impregnation. Zirconia, alumina, and silica sols (ZS, AS and SS) were chosen as impregnating agents for alumina ceramics. The effects of different types of sols, various ratios of alumina sol to silica sol, and different pH values of sols on the mechanical properties of the ceramics were investigated. The flexural strength of the samples increased significantly after silica sol impregnation, reaching a maximum of 63.51 ± 3.67 MPa, which is 2.06 times higher than that of the unimpregnated samples (UN). Silica particles fill the original pores of the ceramics, and after high-temperature sintering, mullite is formed to increase the density and strength of the ceramics. The flexural strength of alumina ceramics decreases and then increases as the percentage of silica sol in the alumina-silica mixed sol increases. The optimal impregnation ratio for the mixed sols was found to be 1:4, which led to a flexural strength of 62.2 ± 2.09 MPa for the alumina ceramics. In addition, the pH of the sol plays a crucial role in maintaining stable sols. The silica sol is more susceptible to gelation as the pH of the sol increases within the range of 3.5–5.5, which can have a negative impact on its impregnation effectiveness. At a pH of 6.5 in the silica sol, the alumina ceramics exhibited the highest flexural strength of 92.57 ± 2.43 MPa, which is 3.01 times higher than the flexural strength of the unimpregnated samples. The research of impregnation process parameters suitable for 3D printing of alumina ceramics aim to enhance the material's strength, offering a novel solution for applications as high-performance components in the energy sector.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2019
·
IF 3.45
Fangming Liu,Jiawei Zhang,Pingping Liu,Qihuang Deng,Duanwei He
High pressure obviously decreased the sintering temperature of high melting point ceramics and produced bulks with excellent mechanical and thermal properties. In this study, the effect of pressure alone on the densification process of alumina ceramics was demonstrated. The translucent alumina bulks with unexpected hardness were obtained by compressing α-Al 2 O 3 powder under ultra-high pressure at room temperature. Through analyzing microstructure and hardness of cold compressed samples, the results reveal that ultra-high pressure could crush alumina grains under appropriate pressure, and initiate plastic deformation of grains when the applied pressure exceeds the yield strength of alumina. Thus to enhance the hardness of the samples by grain boundary strengthening and plastic deformation at higher pressure.
研究领域:
材料科学
·
力学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Jianfeng Wu,Xinxin Shi,Shaoheng Liu,Xiaohong Xu,Yaqiang Shen,Deng Zhang
The absorptivity of endothermic materials serves as a critical index for solar thermal power photothermal conversion systems, and ceramic-based endothermic materials characterized by high absorptivity also exhibit elevated sintering temperatures. In this study, CaF 2 was employed as an additive to investigate its effects on the physical properties and microstructure of the samples, with a particular focus on the mechanism by which CaF 2 reduces the sintering temperature of corundum-based endothermic ceramics. The results showed that the G2 sample (1 wt% CaF 2 ), sintered at 1650 °C, displayed the best physical properties, including 93 % absorptivity, 165.43 MPa bending strength. The sintering temperature of the CaF 2 -doped G-series samples was around 60 °C lower due to liquid-phase calcium hexaaluminate formation from CaF 2 and Al 2 O 3 , which enhanced atomic migration and facilitated ceramic matrix sintering. Additionally, the capillary forces of the liquid-phase calcium hexaaluminate promoted ceramic matrix shrinkage and accelerated corundum-based grain growth through the dissolution-precipitation mechanism, leading to densification. Moreover, the G2 sample exhibited excellent durability, with absorptivity decreasing by only 1.9 % after 100 h at 1000 °C.
研究领域:
材料科学
·
太阳能技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Omega
·
2020
·
IF 2.87
He Li,Yongsheng Liu,Yansong Liu,Kehui Hu,Zhigang Lu,Jingjing Liang
Solvents assist in the debinding of stereolithography-based 3D-printed alumina green bodies. The green bodies subsequently undergo thermal debinding and sintering to obtain alumina ceramics. In this study, several solvents were tested, including polyethylene glycol, oxalic acid, ammonium hydroxide, ethyl alcohol, methyl methacrylate, butyl acetate, dimethyl carbonate, methanol, ethyl acetate, and sec-butyl alcohol. The tested solvents during the debinding process showed different effects on microstructure and properties of 3D-printed alumina ceramics due to the variable aspects of their solubility toward the binders. The microstructure of the samples changed significantly after green bodies underwent solvent debinding, thermal debinding, and sintering, leading to loose spongy structures, porous aggregates, and compact structures, respectively. Shrinkage, bulk density, and open porosity changed slightly due to the debinding function of different solvents. Polyethylene glycol-impregnated samples displayed the minimum shrinkage in length direction (5.3%). Ethyl alcohol-impregnated sample showed minimum shrinkage in width (4.8%) and height (11.5%) directions. Ammonium hydroxide-impregnated samples exhibited minimum bulk density (2.8 g/cm3) and maximum open porosity (28.3%). Dimethyl carbonate-impregnated samples presented minimum flexural strength (32.6 MPa), and oxalic acid-impregnated samples revealed maximum flexural strength (63.4 MPa). In sum, the as-obtained ceramics would be used as ceramic cores for hollow blades in aircraft engines due to their high open porosity and moderate flexural strength.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
International Journal of Applied Ceramic Technology
·
2017
·Vol. 15
·期 3
·633-642
·
IF 1.048
Hui Yu,Zhihao Xu,Ziye Wei,Yongjun Chen,Jianbao Li,Lijie Luo
Alumina (Al 2 O 3 ) ceramics were prepared with nucleating agent of titania (TiO 2 ) and fluxing agent of talc by the normal pressure sintering method. The effects of TiO 2 and talc on phase composition, microstructure, and mechanical properties of Al 2 O 3 ceramics, as well the strengthening and toughening mechanism were investigated. It was found that the introduction of TiO 2 could be favorable for mullite formation and the improved densification of ceramics, resulting in improved mechanical properties of ceramics as well. Ceramics possess the best comprehensive mechanical performance with fracture toughness of 3.69 MPa·m 1/2 and flexural strength of 255.9 MPa when 4 wt.% TiO 2 and 15 wt.% talc were added. Mineral bridges and nanocrystallites were found in the glass-ceramics, which caused the deflection of cracks so that it strengthened the grain boundary and improved the mechanical properties of ceramics.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
REFRACTORIES AND INDUSTRIAL CERAMICS
·
2023
·
IF 0.5
Ding Donghai,Guan Yue,Xiao Guoqing,Mao Zhaoyuan,Shi Xiaoqi,Gao Kaiqiang,Chong Xiaochuan,Luo Jiyuan,Lei Changkun
The alumina ceramics with high compressive strength were prepared by pressureless sintering, and the kaolinite and calcium carbonate were added as Al 2 O 3 –SiO 2 –CaO sintering aids. The effects of sintering temperature on the volume shrinkage, bulk density, water absorption and compressive strength of the alumina ceramics were studied. The phase composition, crystal cell parameters, average grain size and microstructure of the ceramic were analyzed by XRD, SEM and EDS. The results show that the lattice tends to packed with the increase of sintering temperature. The bonding between grains is the most compact after sintering at 1700°C. The volume shrinkage increases with the increase of sintering temperature. The water absorption of alumina ceramics after sintering at 1700°C reaches the minimum value of 0.06%. The bulk density and compressive strength increase first and then decrease with the increase of sintering temperature. At 1700°C, optimized mechanical properties of alumina ceramics is obtained, with a bulk density of 3.80 g/cm 3 and a compressive strength of 1323 MPa.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
DOI
高影响因子
China Foundry
·
2025
·
IF 2.3
Hao Zong-dong,Tang Wei-zhe,Dou Rui,Wang Li
Alumina ceramics are crucial for high-performance applications, such as turbine blades, due to their excellent thermal stability and mechanical properties. However, existing fabrication methods often fail to balance strength, porosity, and dimensional precision. This study partially fills this research gap through a systematic investigation of calcium oxide (CaO) doping effects on alumina ceramic cores fabricated via ceramic stereolithography, with controlled doping ratios and sintering parameters. A ceramic paste was prepared using coarse and fine Al 2 O 3 particles mixed with CaO as a sintering aid, followed by debinding and sintering to achieve optimal mechanical properties. The results show that CaO doping significantly enhances the flexural strength of alumina cores while maintaining porosity levels between 20% and 30% and controlling the sintering shrinkage rate to about 5%. Additionally, CaO doping alters the microstructure by inhibiting the transformation of spherical fine particles into flaky grains, improving sintering activity. However, as the CaO doping content increases, the bending strength increases, while the shrinkage rate of the material also tends to increase, resulting in a reduction in the overall porosity. This has a negative impact on the control of the manufacturing precision of turbine blades. Thus, although CaO doping improves strength and microstructure, achieving necessary dimensional control requires further optimization of doping content and sintering conditions.
研究领域:
材料科学
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陶瓷工程
·
机械性能优化
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Lin-Lin Zhu,Min-Min Dai,Xin Xu,Cheng-Cai Zhao,Guang-Xiang Zhang,Yu-Jian Jian,Wei-Ming Guo,Hua-Tay Lin
The alumina ceramics were joined by spark plasma sintering (SPS) at 1000 °C for 10 min under an applied pressure of 30 MPa using the screen-printed B 2 O 3 as the joining material. The thickness of the interlayers after joining was approximately 5 μm. The average shear strength measured of the joint was 141.9 ± 4.1 MPa, which was the highest value of joined alumina ceramic using B 2 O 3 only ever reported in the open literatures. The presence of Al 4 B 2 O 9 whiskers formed by the in-situ reaction between B 2 O 3 and Al 2 O 3 was assumed to contribute to the strong joint. A sample with extra holding at 400 °C for 10 min before 1000 °C was conducted to investigate the suppression effect of joining parameter on the volatilization of B 2 O 3 . The average shear strength was 104.2 ± 9.4 MPa, which implied that low-temperature holding step promoted rather than suppressed B 2 O 3 volatilization, resulting in lower shear strength.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Qiaoyu Meng,Keqiang Zhang,Shuo Yang,Rujie He,Zhaoliang Qu
Thermal shock resistance is critical to ensure the service safety of ceramic hot-end components. The thermal shock performance of stereolithographic additive-manufactured ceramics has not yet been studied. In this study, a series of thermal shock experiments with various temperature differences was conducted on stereolithographic additive-manufactured Al 2 O 3 ceramics. The surface cracks were analysed based on photographs captured before and after the thermal shock experiments. Three-point bending tests with in situ X-ray digital radiography were conducted to determine the thermal shock resistance. Crack initiation, propagation, and coalescence were observed under flexural loads. The critical temperature difference of the stereolithographic additive-manufactured Al 2 O 3 ceramics was determined to be 267.22 °C. The crack length increased and residual strength decreased with increasing temperature differences. The layered structure of the stereolithographic additive-manufactured ceramics slowed crack propagation . We expect that this study will serve as a reference for the performance of stereolithographic additive-manufactured Al 2 O 3 ceramics in extreme environments.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
·
2024
·Vol. 21
·期 5
·3128-3140
·
IF 1.8
Yang Wang,Zhuoqun Han,Qingxuan Zhou,Yongning Han,Lunan Bi,Xia Zhang,Xiang Lu,Jie Zhao,Wei Chu,Jian Li,Zhicheng Zhao,Yingying Wang,Ling Li,Futian Liu
Digital light processing (DLP) provides a promising avenue for constructing ceramic parts with high precision and complex shapes, yet the inherent brittleness and strength-toughness trade-off hinder their wide applications. Here, according to DLP 3D printing, the textured alumina ceramic components with horizontally aligned textured microstructure were successfully created by adding anisotropically shaped platelets. As a critical process in the preparation of textured ceramics, the alumina platelets were aligned horizontally during printing by using the special shear fields and forming capabilities of DLP technology. The shrinkage, density, microstructure, mechanical performance, and damage-tolerance behavior of alumina parts with different platelet concentrations were examined, and the toughening mechanisms were investigated. The strength and toughness of ceramics with 5 vol.% platelet addition are increased by 22% and 43%, respectively, as compared with those without platelets. The improved damage tolerance capabilities were primarily ascribed to the collaborative toughening mechanisms stimulated by the platelet addition, including crack branching, crack deflection, uncracked-ligament bridging, and platelet pull-out, which increased the crack tortuosity and consumed more fracture energy. The strategy opens up new opportunities to design complex 3D ceramic geometries with bio-inspired layered or textured architectures, providing optimized damage tolerance.
研究领域:
材料科学
·
制造工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Yunzhi Huang,He Li,Chaoke Li,Kehui Hu,Zhigang Lu,Paolo Colombo
For ceramic cores, how to balance porosity and mechanical properties is one of the hot research topics. By adjusting the type and content of the pore-forming agent, the pore distribution and shape of the ceramic can be affected, thus changing the performance of the samples. Therefore, it is important to investigate in detail the processing technology of ceramic cores. Alumina ceramics were prepared by using alumina as raw material and crosslinked polystyrene spheres (20 μm) as a pore-forming agent. The effects of polystyrene content, sintering temperature, and printing method on the properties of the samples were investigated. Alumina ceramics with different polystyrene content were printed in vertical and horizontal printing modes, and then the printed samples were sintered at different sintering temperatures. The properties of the samples were measured by measuring the flexural strength and observing the surface morphology and surface roughness. It was found that in horizontal mode printing, samples with smaller surface roughness and higher flexural strength were be obtained. When the content of polystyrene microspheres was 9%, the overall properties of samples sintered at 1500°C were the best. In these conditions, the flexural strength was 16.67 ± 0.94 MPa, the shrinkage rate 2.25 ± 0.09%, the bulk density 1.87 ± 0.05 g/cm 3 , the open porosity 26.61 ± 0.38%, and the mean roughness 5.70 ± 0.73 μm.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2012
·
IF 4.951
Yingying Hu,Zhaoyin Wen,Xiangwei Wu,Jun Jin
Porous carbon films with tunable pore structure to modify the β″-alumina electrolyte surface are fabricated through a low-cost and direct wet chemistry method with glucose and poly(methyl-methacrylate) (PMMA) as precursors. FTIR analysis confirms the effective connection between the carbohydrate and the pore-forming agent PMMA through hydrogen bonds . The experimental results indicate that the structural parameters of the porous carbon films, including mean pore size and film thickness, can be tuned simply by adjusting the amount of PMMA in the glucose/PMMA composite. This soft-template-assisted method could be readily extended to modify any other ceramic surfaces. The porous carbon films are demonstrated to greatly improve the wettability of the β″-alumina ceramics by molten sodium . Na/β″-alumina/Na cells are used to investigate the interfacial properties between sodium and the β″-alumina electrolyte. The results obtained at 350 °C reveal that the polarization behavior of the cell is alleviated by the porous coating . This work represents a successful method to coat ceramics with porous carbon and offers a promising solution to overcome the polarization problems of the sodium/β″-alumina interface in Na-based batteries .
研究领域:
材料科学
·
电化学
✓ 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）