SOLAR ENERGY
·
2018
·
IF 4.374
Abdelaal S.A. Ahmed,Wanchun Xiang,Xiaowei Hu,Chen Qi,Ibrahim Saana Amiinu,Xiujian Zhao
Si 3 N 4 /MoS 2 nanocomposite has been fabricated through a solvothermal process and Mixed with polystyrenesulfonate-doped poly (3, 4-ethylenedioxythiophene) to prepare (Si 3 N 4 /MoS 2 -PEDOT: PSS) as a counter electrode (CE) for bifacial dye-sensitized solar cells (DSSCs). The electrochemical studies confirm that Si 3 N 4 /MoS 2 -PEDOT: PSS CEs exhibits higher catalytic activity compared with pristine Si 3 N 4 /MoS 2 and PEDOT: PSS. The DSSCs with 5% Si 3 N 4 /MoS 2 -PEDOT: PSS composite CE achieves conversion efficiency (PCE) of 7.16%, which is comparable to that of the conventional platinum CE (7.50%) and better than those of the pristine Si 3 N 4 /MoS 2 (3.80%) or PEDOT: PSS (4.20%) CEs. Owing to the optical transparency of Si 3 N 4 /MoS 2 -PEDOT: PSS composite CEs, bifacial DSSCs based on 5% Si 3 N 4 /MoS 2 -PEDOT: PSS CE yield 2.03% PCE from rear irradiation. The simple preparation method, high catalytic activity and electrochemical stability demonstrate that Si 3 N 4 /MoS 2 -PEDOT: PSS can be used a transparent CE in bifacial DSSCs.
研究领域:
材料科学
·
能源科学
·
纳米技术
✓ 已验证
DOI
高影响因子
Materials
·
2024
·Vol. 17
·期 23
·5830
·
IF 3.1
Qing Qin,Lin Han,Gang Xiong,Zihan Guo,Junwei Huang,Yujuan Zhang,Zhen Shen,Changchun Ge
Digital light processing (DLP) 3D-printed Si₃N₄ ceramics, known for their exceptional performance, offer distinct advantages in meeting the high-strength and complex structural demands of industries such as aerospace, semiconductors, healthcare, automotive, energy, and machinery. However, due to Si₃N₄’s strong chemical stability, low diffusion rate, low self-sintering ability, and high melting point, achieving densification under conventional sintering conditions is challenging. As a result, sintering additives are essential to promote the sintering process, lower the sintering temperature, improve densification, and enhance performance. In this study, 45 vol% Si₃N₄ slurries were prepared using DLP 3D printing technology, incorporating nine different combinations of sintering additives, including aluminum oxide (Al2O3), yttrium oxide (Y2O3), and aluminum nitride (AlN), in various ratios with Si3N4. The slurries were then sintered at 1800 °C for 2 h under a 1 MPa N2atmosphere. Additionally, the phase composition, microstructure, grain distribution, and crack propagation of the materials. The results showed that a Si3N4to Al2O3and Y2O3ratio of 95:2.5:2.5 produced elongated β-Si3N4grain structures and enhanced density, achieving a maximum Vickers hardness of 12.88 ± 0.52 GPa. Additionally, the synergistic toughening effect of the rod-like β-Si3N4grains and sintering aids significantly improved the fracture toughness of the Si3N4ceramic matrix, with a flexural strength of 540.63 ± 10.05 MPa and a fracture toughness of 4.92 ± 0.07 MPa·m1/2. This study lays the foundation for the future application of 3D-printed Si3N4ceramics, optimization of sintering aid combinations at different ratios, and performance enhancement in extreme environments.
研究领域:
材料科学
·
陶瓷工程
·
增材制造
·
机械工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Zhilei Wei,Wenqi Xie,Jiabin Hu,Zhejian Zhang,Biao Zhang,Lei Zhao,Yanjun Li,Bo Wang,Zhongqi Shi
Unidirectional porous (UP) Si 3 N 4 ceramics are promisingly applied in high-temperature filtration devices. However, traditional techniques exhibit the drawbacks of high energy consumption and difficult to control the pore structures. Herein, a novel technique of freeze casting combined with combustion synthesis was proposed to prepare the UP Si 3 N 4 ceramics using Si powder and Si 3 N 4 diluent as raw materials. The effects of Si 3 N 4 diluent content and solid loading on the phase composition, microstructure and permeable/mechanical/filtration properties were investigated systematically. The results showed that the porosity and structure wavelength of UP Si 3 N 4 ceramics with uniform microstructures can be tailored in a wide range of 50.8–86.0 % and 21.7–45.6 μm, respectively. The products exhibited anisotropic compressive strength, good permeable and filtration properties. This novel route with the advantages of energy-saving and high efficiency offers new insights for fabricating UP ceramics.
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
·
2018
·
IF 3.057
Shuang Yin,Limei Pan,Lin Guo,Yun Liu,Yongbao Feng,Tai Qiu,Jian Yang
A low-toxic and water-soluble monomer N, N-dimethylacrylamide (DMAA) was employed as a gelling agent in the gelcasting of porous Si 3 N 4 ceramics. The process conditions and composition for slurry preparation (with a solid loading of 36 vol%), the consolidation and sintering of green bodies were investigated and optimized. The effects of various factors such as zeta potential , pH value of the premix solution, dispersant dosage and ball milling time on the rheological properties of the slurries were investigated. The results suggest that the best rheological properties (66.5 mPa.s at a shear rate of 96.3 s −1 ) of the slurries were obtained when pH value ranged between 9 and 11, dispersant dosage reached 1 wt%, and ball milling time was 6 h. All the as-prepared green bodies showed a homogeneous microstructure and high flexural strength ≥ 26 MPa with a maximum up to 46.3 MPa when the ratio of DMAA to MBAM, initiator dosage, polymerization temperature and time were 14, 1 wt%, 70 °C and 90 min, respectively. The sintered bodies had a homogeneous microstructure, excellent and regulatable properties, a flexural strength of 216.3–327.3 MPa, and a porosity of 39.6–29.1% by varying the sintering temperature from 1710 °C to 1810 °C and the holding time from 1 h to 3 h. The superior comprehensive effect makes DMAA a promising candidate for an environmentally friendly gelling agent in gelcasting of porous Si 3 N 4 ceramics.
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 Central South University
·
2021
·Vol. 28
·期 4
·1233-1243
·
IF 1.716
Rao Wei-dong,Liu Yao,Cheng Li-jing,Liu Shao-jun
Combining sintering additive with field assisted sintering, stereolithographical dense Si 3 N 4 ceramics was successfully fabricated. Owing to a large amount of polymer during the stereolithography, the green parts have the characteristics of low powder loading and high porosity. Adjusting the process parameters such as sintering temperature and soaking time can effectively improve the density of the specimens. The stress exponent n of all specimens is in a range of 1 and 2, which is derived from a modified sintering kinetics model. The apparent activation energy Q d of stereolithographic Si 3 N 4 ceramics sintered with applied pressures of 30 MPa, 40 MPa, and 50 MPa is 384.75, 276.61 and 193.95 kJ/mol, respectively, suggesting that the densification dynamic process is strengthened by raising applied pressure. The grain boundary slipping plays a dominating role in the densification of stereolithographic Si 3 N 4 ceramics. The Vickers hardness and fracture toughness of stereolithographic Si 3 N 4 ceramics are HV10/10 (1347.9±2.4) and (6.57±0.07) MPa·m 1/2 , respectively.
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
International Journal of Applied Ceramic Technology
·
2023
·Vol. 20
·期 6
·3500-3516
·
IF 2.1
Guandong Liang,Jianqiang Bi,Linjing Qiao,Zhuangzhuang Yin,Shaoyin Wang
In view of the lack of conformal, load-bearing, light-weight, and high temperature-resistant integrated wave-absorbing composites suitable for extremely complex conditions, the gel-casting process was successfully applied to porous Si 3 N 4 wave-absorbing composites in this work. A universal low-slurry for gel casting was prepared by using two dispersants acting together (tetramethylammonium hydroxide solution and sodium lauryl sulfate), which ensured the smooth completion of the gel casting process. Combining the thermogravimetric and differential thermal gravity curves of the composite green body, reasonable parameters of the rubber discharge process are given to avoid the problem of the green body swelling and cracking. The porous TiC/Si 3 N 4 composites were successfully prepared by holding them at 1650°C for 3 h. The bending strength, density, minimum reflection loss, absorption bandwidth, and matched thickness in the P-band of the composites with 30 wt.% TiC addition were 54.08 ± 3.02 MPa, 1.906 g/cm 3 , -37.75 dB, 1.9 GHz, and 4.1 mm, respectively. The electromagnetic wave loss mechanisms of the composites are a combination of conductivity loss, multiple reflections and scattering, interfacial polarization, and defect polarization.
研究领域:
材料科学
·
电磁学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 103
·期 10
·5567-5572
·
IF 3.502
Weide Wang,Dongxu Yao,Hanqin Liang,Yongfeng Xia,Kaihui Zuo,Jinwei Yin,Yu-Ping Zeng
A two-step sintering process was conducted to produce β-Si 3 N 4 ceramics with high thermal conductivity. During the first step, native SiO 2 was eliminated, and Y 2 O 3 was in situ generated by a metal hydride reduction process, resulting in a high Y 2 O 3 /SiO 2 ratio. The substitution YH 2 for Y 2 O 3 endow Si 3 N 4 ceramics with an increase of 29% in thermal conductivity from 95.3 to 123 W m −1 K −1 after sintered at 1900°C for 12 hours despite an inferior sinterability. This was primarily attributed to the purified enlarged grains, devitrified grain boundary phase, and reduced lattice oxygen content in the YH 2 -MgO-doped material.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
·
2025
·
IF 7
Yunwei Shi,Qianglong He,Aiyang Wang,Hao Wang,Weimin Wang,Zhengyi Fu
Textured Si 3 N 4 /BN composite ceramics are prepared via combination of PHIP sintering and gas pressure sintering. The mechanical properties of composite ceramics gradually decrease with the increase of BN content. However, the bimodal texture of Si 3 N 4 /BN composite ceramics exhibits a synergistic effect on the anisotropy of thermal and mechanical properties. When the BN content is 20 vol%, The anisotropy of fracture toughness along different testing direction reaches 51.0 %. By the proper regulation of the bimodal texture, Si 3 N 4 /BN composite ceramics could simply realize a high thermal conductivity (99.2 W m −1 k −1 ) and thermal anisotropy (2.1) at low sintering temperature (1800 °C) for short preparation period (4 h). This bimodal texture breaks through the inhibition of the high thermal conductivity of Si 3 N 4 -based ceramics by the amorphous phase of low thermal conductivities. Thus, this new material designs have great advantages in large-scale preparation and directional heat dissipation in the next-generation electric devices.
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
COMPOSITES SCIENCE AND TECHNOLOGY
·
2025
·
IF 9.8
Zhilei Wei,Wenqi Xie,Biao Zhang,Xiaonan Zhou,Yinuo Ma,Lei Zhao,Bo Wang,Zhongqi Shi
Efficient heat dissipation via anisotropic thermal management materials (TMMs) has become increasingly urgent as the microelectronic devices develops towards miniaturization and high integration. However, traditional polymer/ceramic composites suffered from the drawbacks of limited thermal conductivities (TCs) and high coefficients of thermal expansion (CTEs) due to the random dispersion of ceramic grains in the polymer matrices, which resulted in the deteriorated life span of devices. Although recent works successfully constructed anisotropic thermal networks in the polymer-based composites, the connectivity of the ceramic grains was inferior, leading to the high contact thermal resistance ( R cf ) and less constraint of the thermal expansion of polymer matrices. Therefore, achieving high TC while decreasing the CTE of the polymer-based TMMs was still a great challenge. In this work, a novel technique of freeze casting combined with combustion synthesis was employed to fabricate unidirectional porous (UP) Si 3 N 4 ceramics, which were then utilized as the reinforcements for epoxy (EP). The rigid and anisotropic UP Si 3 N 4 skeletons were successfully constructed in the obtained composites, leading to the decreased R cf and enhanced constraint of the thermal expansion of EP. As a consequence, the TCs in the directions parallel and perpendicular to the channels achieved 20.54 W m −1 K −1 and 12.68 W m −1 K −1 , respectively, at a Si 3 N 4 loading of 53.8 vol%. The corresponding CTEs in the above two principal directions were only 11.53 × 10 −6 K −1 and 4.98 × 10 −6 K −1 , respectively. The composites displayed excellent heat dissipation performance in both experimental and simulation results, indicating promising application prospect as TMMs for microelectronic devices.
研究领域:
材料科学
·
热管理材料
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Guanjie Zeng,Xin Li,Yanjing Wei,Tong Guo,Xiaozhong Huang,Xuelong Chen,Xiu-Zhi Tang
Porous ceramic materials with high electromagnetic absorption capacity, low density, high thermal resistance and excellent mechanical properties are highly desirable in aerospace applications. Here, we synthesized one type of hierarchical SiC composite foams with in situ grown Si 3 N 4 nanowires via a pyrolysis process. The existence and structure of Si 3 N 4 nanowires were characterized by multiple techniques and analysis revealed that the growth of nanowires was based on a typical vapor-solid mechanism. Owing to the presence of a large amount of Si 3 N 4 nanowires, both the mechanical performance and electromagnetic absorption were significantly enhanced. The minimum Reflection loss (RL) of 1.25 mm SiC composite foam reaches −50.3 dB at 16.48 GHz with an effective bandwidth (RL < −10 dB) of 3.6 GHz (14.4–18 GHz), while the toughness and specific compressive strength increased by 356% and 126%, respectively. Especially, a ductile and steady fracture behavior was observed for the mechanically enhanced composite foam, rather than the typical catastrophic failure usually seen for ceramic materials. Owing to the excellent electromagnetic wave absorption capability and enhanced mechanical properties, as well as low density and high thermal resistance, this type of composite ceramic material may find applications in aviation, aerospace and other extreme environments.
研究领域:
材料科学
·
航空航天工程
✓ 已验证
DOI
高影响因子
Journal of Advanced Ceramics
·
2021
·Vol. 11
·期 1
·172-183
·
IF 6.707
Chen Shile,Wang Liang,He Gang,Li Jiangtao,Wang Chang-An
Porous silicon nitride ceramics have attracted a considerable attention due to their excellent overall performance, but poor porosity homogeneity and structural shrinkage induced by prolonged high temperature sintering limit its further application. Herein, as a three-in-one solution for the above issues, for the first time we develop a novel approach that integrates the merits of gelcasting-SHS (self-propagating high-temperature synthesis) to prepare porous Si 3 N 4 ceramics to simultaneously achieve high porosity, high strength, high toughness, and low thermal conductivity across a wide temperature range. By regulating the solid content, porous Si 3 N 4 ceramics with homogeneous pore structure are obtained, where the pore size falls inbetween 1.61 and 4.41 µm, and the elongated grains are interlaced and interlocked to form micron-sized coherent interconnected pores. At the same time, porous Si 3 N 4 ceramics with porosity of 67.83% to 78.03% are obtained, where the compressive strength reaches 11.79 to 47.75 MPa and fracture toughness reaches 1.20 to 6.71 MPa·m 1/2 .
研究领域:
材料科学
·
陶瓷工程
·
先进制造
✓ 已验证
产品关联
DOI
高影响因子
Soft Science
·
2025
·Vol. 5
·期 4
·N
·
IF 9
Hailong Xu,Chenyang Jing,Zhijian Xu,Haoyang Zhan,Fang Ye,Qiang Chen,Meng Zhu,Luo Kong,Xinliang Li,Xia Chai,Yuchang Qing,Xiaomeng Fan,Fa Luo
With the ever-deepening understanding of nano-electromagnetic interactions and the advancements of fabrication methodologies of nanomaterials, diverse electromagnetic platforms utilizing nanomaterials have been developed for next-generation electromagnetic safeguarding applications. This study presents the design and fabrication of bioinspired porous Ti2CTX/Si3N4 composites featuring an aligned lamellar structure, aimed at facilitating the effective absorption and dissipation of electromagnetic radiation. The layered configuration of Ti2CTX/Si3N4 composites facilitates the repeated reflection of electromagnetic waves between neighboring Ti2CTX layers, hence enhancing the energy dissipation of these waves. At a Ti2CTX concentration of merely 0.21 wt.%, the effective absorption bandwidth of Ti2CTX/Si3N4 composites encompasses the whole X-band (8.2-12.4 GHz), with a minimum reflection loss of -53 dB achievable at a sample thickness of 5 mm. Simultaneously, the fabricated Ti2CTX/Si3N4 composites demonstrate advantages in lightweight characteristics and robust mechanical properties, offering significant insights for the application of Ti2CTX in nano-electromagnetic engineering, particularly in the realm of electromagnetic pollution mitigation.
研究领域:
材料科学
·
纳米技术
·
电磁工程
·
复合材料
✓ 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）